Glycerol and ascorbic acid-assisted synthesis of α-MoO3 nanoparticles as an efficient catalyst for biodiesel production

doi:10.21203/rs.3.rs-4820789/v1

Download PDF

Research Article

Glycerol and ascorbic acid-assisted synthesis of α-MoO3 nanoparticles as an efficient catalyst for biodiesel production

https://doi.org/10.21203/rs.3.rs-4820789/v1

This work is licensed under a CC BY 4.0 License

You are reading this latest preprint version

This work exhibits a novel method for synthesizing α-MoO₃ nanoparticles (NPs) using a convenient recipe that utilizes glycerol and ascorbic acid as polymerizing and green complexing agents. Different analytical techniques, including XRD, FT-IR, TGA, and scanning electron microscopy (SEM), were employed to identify the as-prepared α-MoO₃ NPs, and it was used as a catalyst in biodiesel production. Moreover, the TPD experiment was performed to determine the catalyst's acidity strength. The α-MoO₃ exhibited high efficiency in producing biodiesel from oleic acid and ethyl alcohol as an oil source and alcohol, respectively. The design of experiments and optimization process were also performed using response surface methodology (RSM) to attain the optimal condition. The influences of several parameters, such as catalyst dosage, reaction time, medium temperature, and alcohol to fatty acid (in molar ratio), were studied. The results demonstrate that at the optimal operating variables of 75°C, 50 min of reaction time, a 30:1 molar ratio of alcohol to oleic acid, and 0.007 g of catalyst, the yield of biodiesel production can approach 85%. Moreover, the obtained results indicated that the catalyst can be efficiently recovered and reused four times without significant loss in its activity.

α-MoO3

Ascorbic acid

Biodiesel

Catalyst

Esterification

RSM

One of the most serious concerns humanity has ever faced is environmental pollution caused by the extensive use of energy for the convenience of modern life (Nomanbhay and Ong, 2017). Therefore, the demand to develop and exploit green fuels has grown steadily (Sales et al., 2023). In recent years, extensive research has been conducted to identify a viable fuel to replace conventional liquid fuels. As a result, biofuels, particularly biodiesel, have attracted a lot of attention. Biodiesel, compared to fossil fuels, has illustrated technical and environmental benefits (Lin et al., 2006). It is a renewable (Farouk et al., 2024; Ngomade et al., 2023; Pandit et al., 2023), biodegradable, non-toxic fuel (Osman et al., 2024), and eco-friendly (Abati et al., 2024). obtained from sources like vegetable oils and animal fats (Lin et al., 2006), and it has great potential as an alternative to fossil fuels (Parida et al., 2024). In general, biodiesel can be produced by various methods such as pyrolysis (Zhang et al., 2020), and transesterification (Ghaffari and Behzad, 2018; Zdujić et al., 2019), but the transesterification process in the presence of a sufficient catalyst is the most efficient (Scragg et al., 2003). This process involves the reaction of an oil source with an alcohol in the presence of a catalyst. Various types of alcohol are utilized in this procedure, including ethanol, methanol, propanol, and others (Salimi and Hosseini, 2019). In this approach, homogeneous and heterogeneous catalysts can be employed; however, separating homogeneous inorganic acid catalysts such as sulfuric acid is challenging and might result in corrosion and contamination of the reaction (Wan et al., 2015). Therefore, developing heterogeneous catalyst systems using green, simple, and cost-effective synthesis techniques is critical to address these issues. In recent years, metal oxides, either as active phases or as supports, have been used as catalysts in many chemical reactions such as the synthesis of methanol (Chang et al., 2019; Wang et al., 2019; Xie et al., 2020), oxidation of various alcohols (Kazemnejadi et al., 2019; Lu et al., 2019; Nasseri et al., 2019), oxidative desulfurization of DBT (Alenazi et al., 2020; Deng et al., 2020; Ghahramaninezhad and Ahmadpour, 2020, 2022), biodiesel production (Huang et al., 2021; Khatibi et al., 2021; Qu et al., 2021) and so on. One type of transition metal oxide is orthorhombic Molybdenum oxide (α-MoO₃), which has attracted much attention from scientists because of its non-toxic nature, high stability, and strong Lewis acid sites (Zhu et al., 2019). Hence, MoO₃ nanoparticles (NPs) are successfully engaged as an efficient catalyst in many chemical reactions, such as in the oxidation of sulfides (Tosi et al., 2018; Wang et al., 2020), methanol oxidation (Peña-Bahamonde et al., 2020; Puebla et al., 2020; Swathi et al., 2020), organic photovoltaics (OPVs) (Choi et al., 2019; Gong et al., 2020), hydrodesulfurization (Li et al., 2020; Yang et al., 2020), gas sensors (Jiang et al., 2019; Zhang et al., 2019), and biodiesel production (Gonçalves et al., 2021; Silva Lucena de Medeiros et al., 2024; Xie and Zhao, 2014). The application of α-MoO₃ nanoparticles as a single-phase bulk active catalyst for biodiesel production is rarely reported (Silva et al., 2022), which can be attributed to the lack of a green, convenient, fast, effective, and low-cost method for its synthesis. For this aim, studying influential factors on the production method of metal oxide nanoparticles from green and cost-effective precursors is very significant.

To date, molybdenum oxide NPs are mainly fabricated from toxic and costly precursors through high energy-consuming procedures (Shaheen and Ahmad, 2021). One of the simple methods for synthesizing metal oxide nanoparticles, including MoO_3, is the sol-gel method (Singh et al., 2018), where a complexing agent and a polymerizing agent are used in the synthesis process. Indeed, the complexing agent prevents the accumulation of particles and prevents the growth of nanoparticles by preventing the formation of larger clusters. The polymerizing agent is also used to homogenize the particle distribution. Due to the simultaneous use of these two agents, this method is sometimes called the PC (polymerizing–complexing) method (Habte et al., 2019). In this research, for the first time, we are offering a green and novel protocol for the synthesis of α-MoO₃ nanoparticles using two green and non-toxic polymerizing and complexing agents, glycerol and ascorbic acid. The as-made α-MoO₃ nanoparticles will then be employed as an efficient and novel catalyst for biodiesel production. The biodiesel production yield is investigated by reacting between oleic acid as an oil source and ethanol in the presence of α-MoO₃ as a catalyst. In typical, temperature, time of reaction, the ratio of alcohol to fatty acid (A/F molar ratio), and catalyst dosage are the most common factors influencing the biodiesel production yield. The optimal conditions for biodiesel production are experimentally assessed using response surface methodology (RSM). After the reaction, the catalyst is easily separated by centrifugation and reused in the process. Moreover, a supposed mechanism for biodiesel production using the as-prepared α-MoO₃ catalyst is presented. Scheme 1 illustrates a basic diagram of biodiesel production via esterification reaction in the presence of α-MoO₃ NPs.

2.1. Chemicals and instruments

All required chemicals and solvents were supplied from SigmaAldrich and used without any additional purification. L-Ascorbic acid (purity > 99%), Glycerol (99%), Ammonium heptamolybdate tetrahydrate (AHM, 99%), Sodium hydroxide, Oleic acid (99%), and ethanol (99.8%) were utilized for α-MoO₃ synthesis. The catalyst's X-ray diffraction (XRD) pattern was attained with a Bruker D8-Advance diffractometer by Cu Kα radiation at room temperature (λ = 0.154 nm). Finally, a scanning electron microscope (SEM, LEO 1450 VP) was used to determine the size and morphology of catalysts. It should be noted that deionized (DI) water is utilized during all experiments.

2.2. Synthesis of α-MoO₃ nanoparticles

To synthesize α-MoO₃ NPs, 0.042 mol ascorbic acid, and 0.021 mol glycerol are added to the solution formed by dissolving 0.007 mol AHM in DI-water and agitated for 10 min at 25°C. The resultant solution was then refluxed for 1 h at 100°C. To make a viscose gel, the solution was slowly heated in an open bath at 80°C for 4 h after the reflux. The viscose gel is then immediately heated to transform into a dry gel. After that, the dried gel was calcined for 2 h at 700°C, and α-MoO₃ NPs were prepared (Scheme 2).

2.3. General procedure for biodiesel production

As shown in Scheme 1, two reagents (oil and alcohol) are required for biodiesel production. Herein, oleic acid was used as an oil source. Ethanol and methanol are the two most common forms of alcohol used in producing biodiesel processes; however, methanol is usually preferred since it is less expensive and has a higher transesterification reactivity than ethanol. Nevertheless, because the utilization of green resources has been at the top of our priorities for environmental protection, ethanol has been utilized as a green source of alcohol in this study. Hence, a certain volume of concentrated oleic acid was added to a required amount of catalyst, and the resulting mixture was stirred at 25°C for 5 min. Then, a determined volume of ethanol was poured into the above mixture, and the reaction mixture was agitated for 25 min at a specific temperature (Scheme 3). The reaction's progress was monitored at regular intervals to determine the yields of the product using the titration method. For this aim, a certain amount of the reaction mixture, around 5 mL, was extracted, and the catalyst was separated by centrifuge. Then, the residual liquid was heated to 150°C for 15 min to remove excess ethanol and water. After that, the titration was fulfilled with a 0.1 N solution of NaOH in the presence of phenolphthalein as an indicator. The endpoint was determined by changing the color from colorless to pink. The yield of biodiesel production is estimated by Eq. (1) (Chang et al., 2013; Sabzevar et al., 2021):

Biodiesel Production Yield (Y%): \(\:(\text{x}-\text{y})\times\:{\text{M}}_{\text{O}\text{A}}\)/[\(\:\text{x}{\text{M}}_{\text{O}\text{A}}+\text{y}\left({\text{M}}_{\text{E}\text{O}}-{\text{M}}_{\text{O}\text{A}}\right)\)]100% (1)

Where M_OA and M_EO are the molecular weights of oleic acid and ethyl oleate, respectively, x is the reaction mixture mass after its heating at 150 ºC, and y is the amount of oleic acid (in mass) calculated by NaOH titration (0.1 M) (Chang et al., 2013; Sabzevar et al., 2021).

2.4. Variable Optimization using RSM

Response surface methodology (RSM) is one of the complete sets of statistical techniques for estimating and obtaining the optimal conditions for stochastic models. This instrumentation was reported in the early 1950s by Box and Wilson (Asadi and Zilouei, 2017; Şenaras, 2019). In this work, experiments utilizing the central composite design (CCD) approach were employed to analyze the main operating variables influencing the yield of the process and to find the optimal operating parameters to achieve the highest yield of biodiesel production. The influence of various variables such as catalyst dosage, alcohol to fatty acid ratio (A/F molar ratio), reaction time, and reaction medium temperature on the process yield was investigated in the presence of α-MoO₃ catalysts. Table 1 shows all variables, their corresponding symbolic names, and the three levels of independent variables evaluated in this study, ranging from − 1 to + 1.

Table 1

Biodiesel production variables and levels used for RSM optimization
Biodiesel Production Variables	Symbols	Range and Levels -1 0 + 1
Temperature (\(\:\text{℃})\)	A	25 5075
Reaction time (min)	B	5 62.5 120
A/F molar ratio	C	10 2030
Catalyst dosage (g)	D	0.001 0.0055 0.01

The connection between operating variables and biodiesel production yield obtained from experimental data was investigated using a second-order polynomial Eq. (2)

Y = \(\:{\beta\:}\)₀ + \(\:{\beta\:}\)₁A + \(\:{\beta\:}\)₂B + \(\:{\beta\:}\)₃C + \(\:{\beta\:}\)₄D + \(\:{\beta\:}\)₅AB + \(\:{\beta\:}\)₆AC + \(\:{\beta\:}\)₇AD + \(\:{\beta\:}\)₈BC + \(\:{\beta\:}\)₉BD + \(\:{\beta\:}\)₁₀CD + \(\:{\beta\:}\)₁₁A² + \(\:{\beta\:}\)₁₂B² + \(\:{\beta\:}\)₁₃C² + \(\:{\beta\:}\)₁₄D² (2)

Y is defined as the response for yield of biodiesel production, and A, B, C, and D are the coded independent variables in this article. β₀ represents the intercept term, and β₁ to β₄ are known as the coefficients indicating the linear effects. The interaction effects of variables are represented by β₅ to β₁₀ cross-product coefficients, and finally, the squared effects are specified by β₁₁, β₁₂, β₁₃, and β₁₄ quadratic coefficients (Omar and Amin, 2011).

3.1. Characterization of Catalyst

To obtain the convenient calcination temperature for the synthesis of α-MoO₃ nanoparticles, thermal analysis was fulfilled from RT to 1000 ºC. As presented in Fig. 1, there are three distinctive peaks at 335, 700, and about 794^◦C. Between 335 ºC to 700 ºC, as shown in Fig. 1, there was no change in the TGA curve, proposing the creation of stable α-MoO₃. Above 700 ºC, the sudden weight loss accrues in the TGA curve and shows the melting point of α-MoO₃. The phase information of the α-MoO₃ nanoparticles was confirmed by XRD. Figure 2 shows the XRD patterns of α-MoO₃. As presented in Fig. 1, the x-ray diffraction pattern of α-MoO₃ nanoparticles displays characteristic peaks at 2θ = 12.68^o, 23.40^o, 25.72^o, 35.55 ^o, 39^o, 45.40^o, 46.20^o, 58.92 ^o, 64.84 ^o and 67.80^o, which correspond to the (020), (110), (040), (041), (060), (200), (210), (081), (062) and (0100) planes, respectively. The results agree with standard JCPDS No. 35–0609 (Abboudi et al., 2018; Chen et al., 2010; Rajagopal et al., 2011; Wongkrua et al., 2013; Zakharova et al., 2018).

3.2. FT-IR characterization

The FT-IR spectrum of α-MoO₃ is represented in the 4000–400 cm^− 1 region. As shown in Fig. 3, the α-MoO₃ nanoparticles mainly show three peaks. The peak at 991 cm^− 1 corresponds to the terminal oxygen symmetry stretching mode of Mo = O, and the presence peak at 858 cm^− 1 is attributed to the symmetry stretching modes of Mo-O-Mo. Moreover, the peak in 571 cm^− 1 contributed to the bending vibration of the oxygen atom connected to three metal atoms. The broadband that appeared at 3434 cm^− 1 contributed to e O − H stretching vibration; also, the peak at 1608 cm^− 1 can be ascribed to the water molecules' vibration due to moisture adsorption (Chen et al., 2010; Umbarkar et al., 2006; Zakharova et al., 2018). The existence of these peaks confirms the successful synthesis of α-MoO₃ nanoparticles.

3.3. SEM analysis

The SEM images of the α-MoO₃ are shown in Fig. 4. As presented, the images exhibited the nanobelts and nanoplates morphology of the preparedα-MoO₃with 0.3–0.8 µm in width and 2.67–6.35 µm in length.

3.4. Acidity investigation of catalyst by TPD-NH₃

The acidic sites of a catalyst play an essential role in carrying out chemical reactions. An ammonia-TPD experiment quantified the acid strength of the catalyst. The TPD profile related to the desorption of NH₃ from the surface of α-MoO₃ is demonstrated in Fig. 5. There are three main areas in the NH₃-TPD profiles: weak, intermediate, and strong acid areas that are located at 100–200, 200–400, and 400–800 ºC, respectively (Umbarkar et al., 2006). Notably, the peaks at the strong acidic region (400–650 ºC) indicate that excellent acidic sites exist on the surface of the MoO₃ catalyst, making it a suitable catalyst for biodiesel production.

3.5. RSM's optimization of biodiesel production

Changes in the amount of process variables substantially impact the yield of biodiesel production. Optimization of operating variables is required to achieve maximum biodiesel yield with minimal energy loss to save time and energy consumption (Hariram et al., 2019). In this study, 29 sets of experiments were designed by RSM, as demonstrated in Table 2. All the experiments were carried out randomly; their corresponding results are listed in Table 2. After optimization, a second-order polynomial equation based on process variables for predicting the response (biodiesel production yield) is proposed, as shown in Eq. 3.

Predicted biodiesel yield = 66.54 + 5.96\(\:\times\:\)A+0.64\(\:\times\:\)B+8.57\(\:\times\:\)C+1.58\(\:\times\:\)D-0.24\(\:\times\:\)AB (3) + 3.89\(\:\times\:\)AC+1.09\(\:\times\:\)AD-0.95\(\:\times\:\)BC+0.3\(\:\times\:\)BD + 1.4\(\:\times\:\)CD-0.52\(\:\times\:\)A²-0.73\(\:\times\:\)B²-0.083\(\:\times\:\)C²-3.83\(\:\times\:\)D²

ANOVA (analysis of variance) table (Table 3) explains the correctness of the predicted model as well as the importance of each variable assessed using a smaller probability value (P value) and a bigger F value. Variables with P values less than 0.05 indicate the significance of the variable (Hariram et al., 2019; Renita A et al., 2014). The good fitting between experimental data and the predicted values from the model (Fig. 6) was well shown by high values of statistical parameters, including R² = 0.975 and R_Adj²= 0.950.

The ANOVA table findings show that the quadratic model chosen for variables optimization is an appropriate and significant method owing to high F-value (F_model= 38.31) with a very low probability value (< 0.0001) (Garba et al., 2017).

Table 2

Design of experiments for esterification of oleic acid using MoO₃catalyst with observed and predicted the yield of biodiesel production
Run	A: Temperature (\(\:\text{℃})\)	B: Tim(min)	C: A/F molar ratio	D: Catalyst dosage (g)	Experimental Biodiesel yield (%)
1	50	62.5	20	0.0055	67.34
2	50	62.5	10	0.001	52.645
3	75	120	20	0.0055	70.02
4	25	62.5	30	0.0055	62.15
5	75	62.5	20	0.01	70.09
6	75	62.5	30	0.0055	84.75
7	50	5	10	0.0055	55.41
8	50	62.5	20	0.0055	67.13
9	75	5	20	0.0055	72.15
10	50	120	30	0.0055	75.12
11	50	120	20	0.01	64.31
12	50	62.5	20	0.0055	66.21
13	75	62.5	20	0.001	64.45
14	25	62.5	20	0.01	58.74
15	25	62.5	20	0.001	57.45
16	50	5	30	0.0055	74.144
17	50	5	20	0.01	61.11
18	50	62.5	30	0.001	68.62
19	50	62.5	20	0.0055	65.822
20	25	120	20	0.0055	58.71
21	25	62.5	10	0.0055	54.14
22	50	120	20	0.001	61.49
23	75	62.5	10	0.0055	61.17
24	50	5	20	0.001	59.48
25	50	62.5	30	0.01	75.22
26	50	62.5	20	0.0055	66.21
27	50	62.5	10	0.01	53.64
28	50	120	10	0.0055	60.18
29	25	5	20	0.0055	59.87

Table 3

ANOVA for the production of biodiesel using the RSM method
Source	Sum of squares	df^a	Mean Square	F-Value	p-value
Model	1518.02	14	108.43	38.31	< 0.0001	significant
A-Temperature	426.86	1	426.86	150.80	< 0.0001
B-Time	4.90	1	4.90	1.73	0.2095
C-A/F molar ratio	880.98	1	880.98	311.23	< 0.0001
D-Catalyst amount	30.00	1	30.00	10.60	0.0057
AB	0.24	1	0.24	0.083	0.7774
AC	60.61	1	60.61	21.41	0.0004
AD	4.73	1	4.73	1.67	0.2170
BC	3.60	1	3.60	1.27	0.2785
BD	0.35	1	0.35	0.13	0.7289
CD	7.85	1	7.85	2.77	0.1180
A²	1.76	1	1.76	0.62	0.4437
B²	3.48	1	3.48	1.23	0.2860
C²	0.045	1	0.045	0.016	0.9014
D²	94.97	1	94.97	33.55	< 0.0001
Residual	39.63	14	2.83
^a Degree of Freedom

The determination of the optimal values for each variable is usually accomplished using three-dimensional graphs. These plots (7a to 7f) show the effect of A/F molar ratio, dosage of catalyst, time of reaction, and temperature of reaction on the biodiesel yield at central point values of variables, i.e., catalyst dosage: 0.0055 g, A/F molar ratio of 20:1, medium temperature: 50°C, and reaction time: 62.5 min.

The conjugate effect of temperature and time of reaction on the yield of biodiesel production is shown in Fig. 7a. It shows that the yield of the process increases piecemeal by time up to 97 min, but after that, at the longer reaction time, the conversion reaches to a constant value due to the equilibrium nature of the esterification reaction. On the other hand, with increasing temperature, the yield of biodiesel increases as the esterification is known as an endothermic reaction, and the higher temperature will result in a higher conversion (Mohebbi et al., 2020). As Fig. 7a exhibits, at the minimum temperature, the reaction conversion of oleic acid decreases to its lowest value (Asgari et al., 2014; Chang et al., 2013; Mohebbi et al., 2020). Therefore, the highest conversion of fatty acid is observed at around 72% at around 97 min and a temperature of 75°C. A similar trend was also observed in the investigation of the conjugate effect of the A/F molar ratio and reaction time variables on the yield of biodiesel production (see Fig. 7b). As it can be observed, with increasing the molar ratio, the yield of biodiesel production increases which is attributed to suppressing of the reverse reaction. In other words, expanding the A/F molar ratio boosts fatty acid conversion to ethyl esters while limiting the reverse reaction (Asgari et al., 2014; Mohebbi et al., 2020). Besides, by increasing the concentration of methanol, the viscosity of the feed mixture decreases, leading to enhanced mass transfer and higher reaction conversion due to better mixing of components (Mohebbi et al., 2020). Hence, based on the results presented in Fig. 7b, the highest percentage of conversion of fatty acid of 74% is obtained after 85 min and at the 30:1 A/F molar ratio. Figure 7c demonstrates the interaction effect of time and catalyst dosage, indicating that the yield of the process improves with the increase in the amount of catalyst when it varies from 0.001 to 0.007 g. This enhancement is more likely because of an increase in the number of active sites and, consequently, contact between methanol and α-MoO₃ catalyst (Mohebbi et al., 2020). Beyond that value, the excessive catalyst will affect the saponification reaction. Hence, it reduces biodiesel yield (Hossain and Mazen, 2010).

Furthermore, it is believed that the mass transfer resistance and the viscosity of the feed reaction will increase by increasing the amount of catalyst, resulting in conversion reduction at a constant stirring rate (Asgari et al., 2014; Mohebbi et al., 2020). Similarly, Fig. 7d illustrates the effect of interaction between the A/F molar ratio and the amount of catalyst. As mentioned earlier, the yield of the process displays a direct relationship with the A/F molar ratio and the amount of catalyst. The maximum conversion value is achieved around 74% at 0.01 g of catalyst and 30:1 A/F molar ratio. On the other hand, Fig. 7e presents the effect of catalyst dosage and temperature interaction. Like previous performances, the yield of the process has been enhanced when the catalyst dosage and temperature increase. Hence, at a temperature of 75°C and 0.01 g of catalyst, the maximum conversion is achieved at around 70%. Finally, Fig. 7f unveils the effect of interaction between the temperature of the reaction medium and the A/F molar ratio. The result shows that the conversion increases as the reaction temperature and A/F ratio increase. Therefore, in a molar ratio equal to 30:1 and a temperature of 75°C, the maximum conversion of around 83% is achievable. Specified levels of effective input parameters must be selected after identifying the most effective operating variables affecting biodiesel production yield. The optimal values of each factor for reaching the highest yield of biodiesel production are shown in Fig. 8. According to these results, by applying the optimal conditions of an amount of adsorbent equal to 0.007 g, a time of reaction of 50 min, temperature medium of 75°C, and alcohol to a fatty acid molar ratio of 30:1, the highest yield value equal to 85% with a desirability amount of 1.00 is obtained. It should be noted that the minimum and maximum production yield of biodiesel is around 52 and 85%, respectively.

Furthermore, the predicted model's accuracy was validated by replicating the experiments (3 times) at optimal conditions. The experimental results unveiled an 85 ± 2% yield for biodiesel production, confirming the regression model's good satisfaction.

3.6. The suggested mechanism of esterification of biodiesel production

The mechanism recommended in this study is in harmony with the previous articles for producing biodiesel in the presence of metal oxide as a catalyst (Essamlali et al., 2017; Rogers and Zheng, 2016). As expected, the surface of the α-MoO₃ nanoparticles can act as Lewis’s acid in catalyzing oleic acid esterification. An electron-poor carbon generally results from the excellent interaction between molybdenum trioxide's acidic site and the oleic acid's carbonyl group. The unpaired electron on the oxygen atom in ethanol as a nucleophile center attacked the electron-poor carbon and formed a tetrahedral intermediate. Eventually, by removing water from the tetrahedral intermediate, ethyl oleate was formed (Scheme 4).

3.7. Stability and recovery study of the MoO₃ catalyst

The recovery of the α-MoO₃ catalyst was simple and efficient from the reaction mixture by centrifuge. Then, the collected catalyst was washed with ethanol, dried under vacuum, and reused directly for the subsequent reaction round without further purification in biodiesel production. As shown in Fig. 9, it was demonstrated that biodiesel production could be recycled four times without a considerable reduction in the catalytic activity of α-MoO₃ nanoparticles. Table 4 also compares the catalytic activity of α-MoO₃ with other catalysts reported in the literature (Al-Saadi et al., 2020; De and Boxi, 2020; Essamlali et al., 2017; Salimi and Hosseini, 2019; Soltani et al., 2020; Xie and Wang, 2020). The production of biodiesel in less time and at a lower temperature than other catalysts and the use of ethanol as green alcohol has made the MoO₃ catalyst a suitable candidate for biodiesel production. Some previous studies, like Ref (De and Boxi, 2020), illustrate milder reaction conditions with almost the same production yield compared to our work. Nonetheless, as mentioned in Table 4, it is because of the difference in the alcohol type that methanol yields a higher conversion in comparison with ethanol (Sabzevar et al., 2021).

Table 4

A comparison of the catalytic activity of α-MoO₃ with other catalysts
Entry	Catalyst	Type of alcohol	Time (min)	Temperature (\(\:\text{℃})\)	Yield (%)	Reference
1	SrO-ZnO/Al₂O₃	Ethanol	180	70	95.1	(71)
2	TiO₂(10)/NP-800	Methanol	480	150	87	(69)
3	Cu-TiO₂	Methanol	45	5	90.93	(72)
4	ZnO/BiFeO₃	Methanol	360	65	95.43	(73)
5	MoO₃/B-ZSM-5	Methanol	360	160	98	(65)
6	ZnO-TiO₂-ICG	Methanol	75	100	96.1	(74)
7	Fe₃O₄/SiO₂	Methanol	360	120	93.3	(75(
8	α-MoO₃	Ethanol	50	75	85	This work

This work proposed a novel method for synthesizing α-MoO₃ nanoparticles (NPs) via a convenient recipe using ascorbic acid and glycerol as green complexing and polymerizing agents. Different methodologies, including XRD, FT-IR, SEM, TPD, and TGA, characterized the as-prepared NPs. Then, the as-prepared NPs were used as a biodiesel production catalyst. The obtained results from the design of experiments unveiled that the optimum values of operating variables for achieving the maximum yield of biodiesel production (85%) are 75°C temperature, 50 min of reaction time, ethanol to an oleic acid molar ratio of 30:1, and 0.007 g of α-MoO₃ catalyst. The stability and recyclability of the catalyst were also confirmed, and a slight reduction was observed after four cycles. The results illustrate the as-made α-MoO₃ NPs as a promising nanocatalyst for industrial applications.

Acknowledgements

The authors are grateful for the financial of the Iranian National Science Foundation (INSF) under grant number 98017245.

Funding

This work was supported by the Iranian National Science Foundation (INSF) under grant number 98017245.

Competing Interests

The authors have no relevant financial or non-financial interests to disclose.

Authors Contributions

Arefe Moatamed Sabzevar: Conceptualization, Investigation, data collection, Visualization, Resources, and Writing–original draft; Mahboube Ghahramaninezhad: Conceptualization, Methodology, Validation, Writing–review & editing, and Project administration.

Ethics declarations

Ethical Approval

Not applicable.

Consent to Participate

All named authors declare that they participated in this work and that the manuscript is original and has not been copied from another source.

Consent to Publish

All authors consent to the publication of this manuscript.

Data Availability Statement

The data of this study will be available upon reasonable request from the corresponding author.

Abati SM, Bamisaye A, Adaramaja AA, Ige AR, Adegoke KA, Ogunbiyi EO, Idowu MA, Olabintan AB, Saleh TA (2024) Biodiesel production from spent vegetable oil with Al₂O₃ and Fe₂O₃-biobased heterogenous nanocatalysts: Comparative and optimization studies. Fuel 364:130847. https://doi.org/10.1016/j.fuel.2023.130847.
Abboudi M, Oudghiri-Hassani H, Al Wadaani F, Rakass S, Al Ghamdi A, Messali M (2018) Enhanced catalytic reduction of para-nitrophenol using α-MoO₃ molybdenum oxide nanorods and stacked nanoplates as catalysts prepared from different precursors. Journal of Taibah University for Science 12:133-137. https://doi.org/10.1080/16583655.2018.1451102.
Al-Saadi A, Mathan B, He Y (2020) Esterification and transesterification over SrO–ZnO/Al₂O₃ as a novel bifunctional catalyst for biodiesel production. Renewable Energy 158:388-399. https://doi.org/10.1016/j.renene.2020.05.171.
Alenazi B, Alsalme A, Alshammari SG, Khan RA, Siddiqui MRH (2020) Ionothermal Synthesis of Metal Oxide‐Based Nanocatalysts and Their Application towards the Oxidative Desulfurization of Dibenzothiophene. Journal of Chemistry 2020:3894804. https://doi.org/10.1155/2020/3894804.
Asadi N, Zilouei H (2017) Optimization of organosolv pretreatment of rice straw for enhanced biohydrogen production using Enterobacter aerogenes. Bioresource technology 227:335-344. https://doi.org/10.1016/j.biortech.2016.12.073. https://doi.org/10.1016/j.biortech.2016.12.073.
Asgari S, Fakhari Z, Berijani S (2014) Synthesis and characterization of Fe₃O₄ magnetic nanoparticles coated with carboxymethyl chitosan grafted sodium methacrylate. http://doi.org/10.7508/jns.2014.01.007.
Chang B, Fu J, Tian Y, Dong X (2013) Soft-template synthesis of sulfonated mesoporous carbon with high catalytic activity for biodiesel production. RSC advances 3:1987-1994. https://doi.org/10.1039/C2RA21982D.
Chang K, Wang T, Chen JG (2019) Methanol synthesis from CO₂ hydrogenation over CuZnCeTi mixed oxide catalysts. Industrial & Engineering Chemistry Research 58:7922-7928. https://doi.org/10.1021/acs.iecr.9b00554.
Chen Y, Lu C, Xu L, Ma Y, Hou W, Zhu J-J (2010) Single-crystalline orthorhombic molybdenum oxide nanobelts: synthesis and photocatalytic properties. CrystEngComm 12:3740-3747. https://doi.org/10.1039/C000744G.
Choi S, Kim W, Shin W, Park S, Lee H (2019) Effect of Deposition Sequence in MoO₃ and HAT-CN Dual-anode Buffer Layer on Inverted Organic Photovoltaics. Applied Science and Convergence Technology 28:217-220. http//doi.org/10.5757/ASCT.2019.28.6.217.
De A, Boxi SS (2020) Application of Cu impregnated TiO₂ as a heterogeneous nanocatalyst for the production of biodiesel from palm oil. Fuel 265:117019. https://doi.org/10.1016/j.fuel.2020.117019.
Deng C, Wu P, Zhu L, He J, Tao D, Lu L, He M, Hua M, Li H, Zhu W (2020) High-entropy oxide stabilized molybdenum oxide via high temperature for deep oxidative desulfurization. Applied Materials Today 20:100680. https://doi.org/10.1016/j.apmt.2020.100680.
Essamlali Y, Larzek M, Essaid B, Zahouily M (2017) Natural phosphate supported titania as a novel solid acid catalyst for oleic acid esterification. Industrial & Engineering Chemistry Research 56:5821-5832. https://doi.org/10.1021/acs.iecr.7b00607.
Farouk SM, Tayeb AM, Abdel-Hamid SM, Osman RM (2024) Recent advances in transesterification for sustainable biodiesel production, challenges, and prospects: a comprehensive review. Environmental Science and Pollution Research 31:12722-12747. https://doi.org/10.1007/s11356-024-32027-4.
Garba A, Abarshi M, Shuaib M, Sulaiman R (2017) Optimization of biodiesel production from castor oil by response surface methodology. Nigerian Journal of Biotechnology 33:66-71. http://doi.org/ 10.1007/s12010-008-8468-9.
Ghaffari A, Behzad M (2018) Facile synthesis of layered sodium disilicates as efficient and recoverable nanocatalysts for biodiesel production from rapeseed oil. Advanced Powder Technology 29:1265-1271. https://doi.org/10.1016/j.apt.2018.02.019.
Ghahramaninezhad M, Ahmadpour A (2020) A new simple protocol for the synthesis of nanohybrid catalyst for oxidative desulfurization of dibenzothiophene. Environmental Science and Pollution Research 27:4104-4114. https://doi.org/10.1007/s11356-019-07048-z.
Ghahramaninezhad M, Ahmadpour A (2022) Carboxylmethyl-β-cyclodextrin as a good modifier agent for oxidation of dibenzothiophene. Surfaces and Interfaces 28:101612. https://doi.org/10.1016/j.surfin.2021.101612.
Gonçalves MA, Mares EKL, Zamian JR, da Rocha Filho GN, da Conceição LRV (2021) Statistical optimization of biodiesel production from waste cooking oil using magnetic acid heterogeneous catalyst MoO₃/SrFe₂O₄. Fuel 304:121463. https://doi.org/10.1016/j.fuel.2021.121463.
Gong Y, Dong Y, Zhao B, Yu R, Hu S, Tan Za (2020) Diverse applications of MoO₃ for high performance organic photovoltaics: fundamentals, processes and optimization strategies. Journal of Materials Chemistry A 8:978-1009. https://doi.org/10.1039/C9TA12005J.
Habte L, Shiferaw, N, Mulatu, D, Thenepalli, T, Chilakala, R, Ahn, JW (2019) Synthesis of nano-calcium oxide from waste eggshell by sol-gel method. Sustainability 11:3196. https://doi.org/10.3390/su11113196.
Hariram V, Bose A, Seralathan S (2019) Dataset on optimized biodiesel production from seeds of Vitis vinifera using ANN, RSM and ANFIS. Data in brief 25:104298. https://doi.org/10.1016/j.dib.2019.104298.
Hossain AB, Mazen M (2010) Effects of catalyst types and concentrations on biodiesel production from waste soybean oil biomass as renewable energy and environmental recycling process. Australian journal of crop science 4:550-555.
Huang J, Zou Y, Yaseen M, Qu H, He R, Tong Z (2021) Fabrication of hollow cage-like CaO catalyst for the enhanced biodiesel production via transesterification of soybean oil and methanol. Fuel 290:119799. https://doi.org/10.1016/j.fuel.2020.119799.
Jiang W, Meng L, Zhang S, Chuai X, Zhou Z, Hu C, Sun P, Liu F, Yan X, Lu G (2019) Design of highly sensitive and selective xylene gas sensor based on Ni-doped MoO₃ nano-pompon. Sensors and Actuators B: Chemical 299:126888. https://doi.org/10.1016/j.snb.2019.126888.
Kazemnejadi M, Alavi SA, Rezazadeh Z, Nasseri MA, Allahresani A, Esmaeilpour M (2019) Fe₃O₄@SiO₂@Im[Cl]Mn(III)-complex as a highly efficient magnetically recoverable nanocatalyst for selective oxidation of alcohol to imine and oxime. Journal of Molecular Structure 1186:230-249. https://doi.org/10.1016/j.molstruc.2019.03.008.
Khatibi M, Khorasheh F, Larimi A (2021) Biodiesel production via transesterification of canola oil in the presence of Na–K doped CaO derived from calcined eggshell. Renewable Energy 163:1626-1636. https://doi.org/10.1016/j.renene.2020.10.039.
Li S-W, Wang W, Zhao J-S (2020) Catalytic oxidation of DBT for ultra-deep desulfurization under MoO₃modified magnetic catalyst: the comparison influence on various morphologies of MoO₃. Applied Catalysis A: General 602:117671. https://doi.org/10.1016/j.apcata.2020.117671.
Lin C-Y, Lin H-A, Hung L-B (2006) Fuel structure and properties of biodiesel produced by the peroxidation process. Fuel 85:1743-1749. https://doi.org/10.1016/j.fuel.2006.03.010.
Lu G, Huang X, Wu Z, Li Y, Xing L, Gao H, Dong W, Wang G (2019) Construction of covalently integrated core-shell TiO₂ nanobelts@COF hybrids for highly selective oxidation of alcohols under visible light. Applied Surface Science 493:551-560. https://doi.org/10.1016/j.apsusc.2019.06.265.
Mohebbi S, Rostamizadeh M, Kahforoushan D (2020) Effect of molybdenum promoter on performance of high silica MoO₃/B-ZSM-5 nanocatalyst in biodiesel production. Fuel 266:117063. https://doi.org/10.1016/j.fuel.2020.117063.
Nasseri MA, Hemmat K, Allahresani A, Hamidi‐Hajiabadi E (2019) CoFe₂O₄@SiO₂@Co(III) salen complex nanoparticle as a green and efficient magnetic nanocatalyst for the oxidation of benzyl alcohols by molecular O2. Applied Organometallic Chemistry 33:e4809. https://doi.org/10.1002/aoc.4809.
Ngomade SBL, Fotsop CG, Nguena KLT, Tchummegne IK, Ngueteu MLT, Tamo AK, Nche GN-A, Anagho SG (2023) Catalytic performances of CeO₂@SBA-15 as nanostructured material for biodiesel production from Podocarpus falcatus oil. Chemical Engineering Research and Design 194:789-800. https://doi.org/10.1016/j.cherd.2023.05.010.
Nomanbhay S, Ong MY (2017) A review of microwave-assisted reactions for biodiesel production. Bioengineering 4:57. http://doi.org/10.3390/bioengineering4020057
Omar WNNW, Amin NAS (2011) Optimization of heterogeneous biodiesel production from waste cooking palm oil via response surface methodology. Biomass and bioenergy 35:1329-1338. https://doi.org/10.1016/j.biombioe.2010.12.049.
Osman AI, Nasr M, Farghali M, Rashwan AK, Abdelkader A, Al-Muhtaseb, AaH, Ihara I, Rooney, DW (2024) Optimizing biodiesel production from waste with computational chemistry, machine learning and policy insights: a review. Environmental Chemistry Letters 22:1005-1071. https://doi.org/10.1007/s10311-024-01700-y.
Pandit C, Banerjee S, Pandit S, Lahiri D, Kumar V, Chaubey, KK, Al-Balushi R, Al-Bahry S, Joshi, SJ (2023) Recent advances and challenges in the utilization of nanomaterials in transesterification for biodiesel production. Heliyon 9. https://doi.org/10.1016/j.heliyon.2023.e15475.
Parida S, Pali HS, Chaturvedi A, Sharma A, Balasubramanian D, Ramegouda R, Tran VD, Nguyen VG, Shobanabai FJJ, Varuvel EG (2024) Production of biodiesel from waste fish fat through ultrasound-assisted transesterification using petro-diesel as cosolvent and optimization of process parameters using response surface methodology. Environmental Science and Pollution Research 31:25524-25537. https://doi.org/10.1007/s11356-024-32702-6.
Peña-Bahamonde J, Wu C, Fanourakis SK, Louie SM, Bao J, Rodrigues DF (2020) Oxidation state of Mo affects dissolution and visible-light photocatalytic activity of MoO₃ nanostructures. Journal of Catalysis 381:508-519. https://doi.org/10.1016/j.jcat.2019.11.035.
Puebla S, Mariscal-Jiménez A, Galán RS, Munuera C, Castellanos-Gomez A (2020) Optical-based thickness measurement of MoO₃ nanosheets. Nanomaterials 10:1272. https://doi.org/10.3390/nano10071272.
Qu T, Niu S, Zhang X, Han K, Lu C (2021) Preparation of calcium modified Zn-Ce/Al₂O₃ heterogeneous catalyst for biodiesel production through transesterification of palm oil with methanol optimized by response surface methodology. Fuel 284:118986. https://doi.org/10.1016/j.fuel.2020.118986.
Rajagopal S, Nataraj D, Khyzhun, OY, Djaoued Y, Robichaud J, Senthil K, Mangalaraj D (2011) Systematic synthesis and analysis of change in morphology, electronic structure and photoluminescence properties of pyrazine intercalated MoO₃ hybrid nanostructures. CrystEngComm 13:2358-2368. https://doi.org/10.1039/C0CE00303D.
Renita A A, Sreedhar N, Peter D M (2014) Optimization of algal methyl esters using RSM and evaluation of biodiesel storage characteristics. Bioresources and Bioprocessing 1:1-9. https://doi.org/10.1186/s40643-014-0019-3.
Rogers KA, Zheng Y (2016) Selective deoxygenation of biomass‐derived bio‐oils within hydrogen‐modest environments: a review and new insights. ChemSusChem 9:1750-1772. https://doi.org/10.1002/cssc.201600144.
Sabzevar AM, Ghahramaninezhad M, Shahrak MN (2021) Enhanced biodiesel production from oleic acid using TiO₂-decorated magnetic ZIF-8 nanocomposite catalyst and its utilization for used frying oil conversion to valuable product. Fuel 288:119586. https://doi.org/10.1016/j.fuel.2020.119586.
Sales HB, de Oliveira, MS, Macário, SN, de Andrade, GG, da Silva, AL, Alves, MCF, de Melo Costa, ACF (2023) MoO₃/ironepinelium catalyst supported on ornamental rock residues with potential application in biodiesel production. Revista de Gestão e Secretariado 14:14971-14991. http://doi.org/ DOI:10.7769/gesec.v14i9.2622.
Salimi Z, Hosseini SA (2019) Study and optimization of conditions of biodiesel production from edible oils using ZnO/BiFeO₃ nano magnetic catalyst. Fuel 239:1204-1212. https://doi.org/10.1016/j.fuel.2018.11.125.
Scragg A, Morrison J, Shales S (2003) The use of a fuel containing Chlorella vulgaris in a diesel engine. Enzyme and Microbial Technology 33:884-889. https://doi.org/10.1016/j.enzmictec.2003.01.001.
Şenaras AE, (2019) Parameter optimization using the surface response technique in automated guided vehicles, Sustainable Engineering Products and Manufacturing Technologies. Elsevier 187-197. https://doi.org/10.1016/B978-0-12-816564-5.00008-6.
Shaheen I, Ahmad KS (2021) Modified sol gel synthesis of MoO₃ NPs using organic template: Synthesis, characterization and electrochemical investigations. Journal of Sol-Gel Science and Technology 97:178-190. https://doi.org/10.1016/j.arabjc.2022.104012.
Silva AL, Farias AFF, Meneghetti SMP, dos Santos Filho EA, de Melo Costa ACF (2022) Optimization of biodiesel production via transesterification of soybean oil using α-MoO₃ catalyst obtained by the combustion method. Arabian Journal of Chemistry 15:104012. https://doi.org/10.1016/j.arabjc.2022.104012.
Silva Lucena de Medeiros SA, Menezes de Oliveira AL, Duarte TM, Kennedy BJ, Rostas AM, Negrila CC, Galca AC, da Silva Maia A, Sambrano JR, Dantas MC (2024) α-MoO₃ Micro-and Nanoparticles as Catalysts for Biofuel Production. ACS Applied Nano Materials. http://doi.org/10.1021/acsanm.4c01239.
Singh J, Dutta T, Kim K-H, Rawat M, Samddar P, Kumar P (2018) Green’synthesis of metals and their oxide nanoparticles: applications for environmental remediation. Journal of nanobiotechnology 16:1-24. https://doi.org/10.1186/s12951-018-0408-4.
Soltani S, Khanian N, Rashid U, Choong TSY (2020) Core-shell ZnO-TiO₂ hollow spheres synthesized by in-situ hydrothermal method for ester production application. Renewable Energy 151:1076-1081. https://doi.org/10.1016/j.renene.2019.11.110.
Swathi S, Ravi G, Yuvakkumar R, Hong S, Babu ES, Velauthapillai D, Kumar P (2020) Water-splitting application of orthorhombic molybdite α-MoO₃ nanorods. Ceramics International 46:23218-23222. https://doi.org/10.1016/j.ceramint.2020.06.104.
Tosi I, Vurchio C, Abrantes M, Gonçalves IS, Pillinger M, Cavani F, Cordero FM, Brandi A (2018) [MoO₃ (2,2′–bipy)]_n catalyzed oxidation of amines and sulfides. Catalysis Communications 103:60-64. https://doi.org/10.1016/j.catcom.2017.09.022.
Umbarkar S, Biradar A, Mathew S, Shelke S, Malshe K, Patil P, Dagde S, Niphadkar S, Dongare M (2006) Vapor phase nitration of benzene using mesoporous MoO₃/SiO₂ solid acid catalyst. Green Chemistry 8:488-493. https://doi.org/10.1039/B600094K.
Wan H, Chen C, Wu Z, Que Y, Feng Y, Wang W, Wang L, Guan G, Liu X (2015) Encapsulation of heteropolyanion‐based ionic liquid within the metal–organic framework MIL‐100(Fe) for biodiesel production. ChemCatChem 7:441-449. https://doi.org/10.1002/cctc.201402800.
Wang D, Cheng Y, Wan K, Yang J, Xu J, Wang X (2020) High efficiency xylene detection based on porous MoO₃ nanosheets. Vacuum 179:109487. https://doi.org/10.1016/j.vacuum.2020.109487.
Wang G, Mao D, Guo X, Yu J (2019) Methanol synthesis from CO₂ hydrogenation over CuO-ZnO-ZrO₂-M_xO_y catalysts (M= Cr, Mo and W). International Journal of Hydrogen Energy 44:4197-4207. https://doi.org/10.1016/j.ijhydene.2018.12.131.
Wongkrua P, Thongtem T, Thongtem S (2013) Synthesis of h‐and α‐MoO₃ by Refluxing and Calcination Combination: Phase and Morphology Transformation, Photocatalysis, and Photosensitization. Journal of Nanomaterials 2013:702679. https://doi.org/10.1155/2013/702679.
Xie B, Wong RJ, Tan TH, Higham M, Gibson EK, Decarolis D, Callison J, Aguey-Zinsou, K-F, Bowker M, Catlow CRA (2020) Synergistic ultraviolet and visible light photo-activation enables intensified low-temperature methanol synthesis over copper/zinc oxide/alumina. Nature Communications 11:1615. https://doi.org/10.1038/s41467-020-15445-z.
Xie W, Wang H (2020) Immobilized polymeric sulfonated ionic liquid on core-shell structured Fe₃O₄/SiO₂ composites: A magnetically recyclable catalyst for simultaneous transesterification and esterifications of low-cost oils to biodiesel. Renewable Energy 145:1709-1719. https://doi.org/10.1016/j.renene.2019.07.092.
Xie W, Zhao L (2014) Heterogeneous CaO–MoO₃–SBA-15 catalysts for biodiesel production from soybean oil. Energy conversion and management 79:34-42. https://doi.org/10.1016/j.enconman.2013.11.041.
Yang G, Yang H, Zhang X, Feng F, Ma J, Qin J, Yuan F, Cai Y, Ma J (2020) Surfactant-free self-assembly to the synthesis of MoO₃ nanoparticles on mesoporous SiO₂ to form MoO₃/SiO₂ nanosphere networks with excellent oxidative desulfurization catalytic performance. Journal of Hazardous Materials 397:122654. https://doi.org/10.1016/j.jhazmat.2020.122654.
Zakharova GS, Schmidt C, Ottmann A, Mijowska E, Klingeler R (2018) Microwave-assisted hydrothermal synthesis and electrochemical studies of α-and h-MoO₃. Journal of Solid State Electrochemistry 22:3651-3661. https://doi.org/10.1007/s10008-018-4073-1.
Zdujić M, Lukić I, Kesić Ž, Janković-Častvan I, Marković S, Jovalekić, Č, Skala, D (2019) Synthesis of CaOSiO₂ compounds and their testing as heterogeneous catalysts for transesterification of sunflower oil. Advanced Powder Technology 30:1141-1150. https://doi.org/10.1016/j.apt.2019.03.009.
Zhang F, Dong X, Cheng X, Xu Y, Zhang X, Huo, L (2019) Enhanced gas-sensing properties for trimethylamine at low temperature based on MoO₃/Bi₂Mo₃O₁₂ hollow microspheres. ACS Applied Materials & Interfaces 11:11755-11762. https://doi.org/10.1021/acsami.8b22132.
Zhang Y, Cui Y, Liu S, Fan L, Zhou N, Peng P, Wang Y, Guo F, Min M, Cheng Y (2020) Fast microwave-assisted pyrolysis of wastes for biofuels production–A review. Bioresource technology 297:122480. https://doi.org/10.1016/j.biortech.2019.122480.
Zhu Y, Yao Y, Luo Z, Pan C, Yang J, Fang Y, Deng H, Liu C, Tan Q, Liu F (2019) Nanostructured MoO₃for efficient energy and environmental catalysis. Molecules 25:18. http://doi.org/10.3390/molecules25010018.

Schemes 1 to 4 are available in the Supplementary Files section.

GraphicalAbstract.jpg
Graphical abstract
Scheme.1.jpg
Scheme. 1 A simple schematic of esterification reaction using α-MoO₃catalyst
Scheme2.jpg
Scheme. 2 A simple schematic of the synthesis of α-MoO₃nanoparticles method.
Scheme.3.jpg
Scheme. 3 Schematic for evaluation of biodiesel production using α-MoO₃catalyst.
Scheme.4.jpg
Scheme. 4 Suggested mechanisms for the esterification of biodiesel production using α-MoO₃ catalyst

Download PDF

Editorial decision: Major Revision
26 Sep, 2024
Reviewers agreed at journal
02 Sep, 2024
Reviewers invited by journal
02 Sep, 2024
Editor invited by journal
02 Sep, 2024
Editor assigned by journal
01 Aug, 2024
First submitted to journal
30 Jul, 2024

You are reading this latest preprint version

Glycerol and ascorbic acid-assisted synthesis of α-MoO3 nanoparticles as an efficient catalyst for biodiesel production

Status:

Version 1

Abstract

Figures

1. Introduction

2. General Experimentation and Methodologies

2.1. Chemicals and instruments

2.2. Synthesis of α-MoO₃ nanoparticles

2.3. General procedure for biodiesel production

2.4. Variable Optimization using RSM

3. Results and discussion

3.1. Characterization of Catalyst

3.2. FT-IR characterization

3.3. SEM analysis

3.4. Acidity investigation of catalyst by TPD-NH₃

3.5. RSM's optimization of biodiesel production

3.6. The suggested mechanism of esterification of biodiesel production

3.7. Stability and recovery study of the MoO₃ catalyst

4. Conclusion

Declarations

References

Schemes

Supplementary Files

Status:

Version 1

Glycerol and ascorbic acid-assisted synthesis of α-MoO3 nanoparticles as an efficient catalyst for biodiesel production

Status:

Version 1

Abstract

Figures

1. Introduction

2. General Experimentation and Methodologies

2.1. Chemicals and instruments

2.2. Synthesis of α-MoO3 nanoparticles

2.3. General procedure for biodiesel production

2.4. Variable Optimization using RSM

3. Results and discussion

3.1. Characterization of Catalyst

3.2. FT-IR characterization

3.3. SEM analysis

3.4. Acidity investigation of catalyst by TPD-NH3

3.5. RSM's optimization of biodiesel production

3.6. The suggested mechanism of esterification of biodiesel production

3.7. Stability and recovery study of the MoO3 catalyst

4. Conclusion

Declarations

References

Schemes

Supplementary Files

Status:

Version 1

2.2. Synthesis of α-MoO₃ nanoparticles

3.4. Acidity investigation of catalyst by TPD-NH₃

3.7. Stability and recovery study of the MoO₃ catalyst