MoO3 Structures Transition from Nanoflowers to Nanorods and Their Sensing Performances

doi:10.21203/rs.3.rs-283514/v1

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MoO3 Structures Transition from Nanoflowers to Nanorods and Their Sensing Performances

https://doi.org/10.21203/rs.3.rs-283514/v1

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Morphology transformation and crystal growth strategies of metal oxide semiconductors are extensive studied in material science recently, because the morphology and crystallinity of the nanomaterial have significant effect on the physicochemical characteristics. However, understanding the morphology changes of α-MoO₃ induced by annealing temperature is still a challenge. Herein, the nanostructure transition of MoO₃ induced by calcined temperature has been investigated through XRD and SEM method. It can be found that crystallization is highly dependent on the annealing temperature. In addition, the MoO₃ nanoflowers can change into nanosheets at 500 ºC. Afterwards, the nanosheets turn into microrods, especially at 900 ºC due to the growth of MoO₃ crystal. On the other hand, MoO₃ is a traditional sensing material, which is sensitive to many volatile organic compounds. Thus, the sensing performances of various MoO₃ nanostructures were measured. Compared with MoO₃ nanoflowers and microrods. The MoO₃ nanosheets based sensor has excellent sensing performance towards ethanol, and the maximum gas response value is 8.06.

Electrophysics

Electronic Materials and Devices

Electrochemistry

MoO3

annealing temperature

morphology

crystallization

ethanol sensing performance

In the past few decades, the development of nanotechnology and band gap engineering have created various exotic metal oxide semiconductor (MOS) nanostructures, which open up new perspectives for their exploitation, significantly creating the novel and fascinating devices [1–5]. Consequently, metal oxide semiconductors have attracted significant attention in recent years for their applications to the secondary cells, sensors, memories, photodetectors, field-effect transistors, and heavy metal etc. [6–12]. For example, the traditional semiconductors of MoO₃ [13], In₂O₃ [14], TiO₂ [15] and ZnO [16], owing to their useful features such as exotic electronic structure, well chemical stability, non-toxicity, rich optoelectronic properties, low cost, high surface-to volume ratio and considerable sensitivity at low temperatures, have been regarded as the attractive materials for the quantum dots sensitized solar cells, lighting emitting components, high frequency devices, and catalysts [17–20]. On the other hand, the above physicochemical characteristics strongly depend on their shape and size, as well as morphology and crystallinity [21, 22].

Besides, nanostructure transformation and crystal growth are very important to fabricate the optoelectronic devices with superior performances [23]. Specifically, nanostructure design strategies offer interesting and extensive ideas to validly synthesis favorable functional nanomaterials due to its distinct characteristics at the nanoscale. For example, ultrafine NiO nanoparticles were acquired in situ by the approach of converting three-dimensional (3D) metal boron organic polymer into one dimensional (1D) boron organic polymer nanorod array at room temperature [24]. In addition, the facile advance of MgO nanostructures at different annealing temperatures (from 300 to 900 ºC) was developed [25]. Moreover, crystal quality is one of the other important factors for optoelectronic device. Recently, Jang and his coworkers observed the homoepitaxial growth of nanowires with constant outer diameters on bulk materials [26]. Additionally, high performance photodetector based on p-type Cu_1 − xNi_xO films were prepared, and the crystal quality, morphology, and grain size of Cu_1 − xNi_xO films can be manipulated by Ni doping [27]. Of course, crystal growth and its quality are known to be significantly influenced by the crystallization environment.

As a representative n-type semiconductor oxide material with an energy gap of about 3.2 eV, molybdenum oxide (MoO₃) has been extensively used in various devices such as sensors, lithium-ion batteries, and photodetectors due to the high thermal and chemical stability [28–30]. Owing to different experimental conditions, MoO₃ exhibits many nanostructures, for example, nanoribbons, nanosheets, nanowires, nanoflowers and nanorods [29–31]. Consequently, the research regarding MoO₃ nanostructure has gained popularity. However, the morphology transformation induced by annealing temperature is not yet well researched.

Herein, the MoO₃ nanostructure transformation and crystal quality induced by annealing temperature is more compelling. The crystalline MoO₃ was obtained from MoS₂ precursor calcined in the range of 400–900 ºC in air, respectively. The results show that the nanostructure can be manipulated from nanoflowers to nanorods via alteration of annealing temperature.

2.1 Materials

Commercially available solvents and metal salts were used without further purification. Specifically, Ammonium molybdate ((NH₄)₂MoO₄), glucose (C₆H₁₂O₆), ammonium fluoride (NH₄F), Thiourea (CH₄N₂S), trimethylamine (C₆H₁₅N) were purchased commercially from Aladdin company, China.

2.2 Fabrication of MoO₃ materials

The flower-shaped MoS₂ was synthesized by hydrothermal processes similar to our previous study [28]. In a typical synthesis, 1.8 g ammonium molybdate, 1.8 g thiourea, 1 g glucose, firstly, to add 200 mg of ammonium fluoride into 50 mL distilled water, then triethylamine (200 µL) was dropped slowly with a pipette, and stirred vigorously for 30 min. Afterwards, the resulting mixtures were sealed in a 60 mL Teflon-lined stainless-steel autoclave and heated at 200 ºC for 24 h, after which the mixtures were cooled to room temperature over 500 min. Thereafter, in the processes of ultrasonicating and centrifuging, the obtained MoS₂ suspension was washed several times with absolute ethanol and deionized water to eliminate redundant ions, respectively. The dark flowerlike powders were obtained after dried overnight in vacuum at 80 ºC; secondly, the MoS₂ precursor was calcined at 400 ºC, 500 ºC, 600 ºC, 700 ºC, 800 ºC and 900 ºC for 2 h, respectively. All heating rates were set at 1 ᵒC/min. For convenience, the name of the above samples was defined as MoO₃-400, MoO₃-500, MoO₃-600, MoO₃-700, MoO₃-800, and MoO₃-900 according to the calcination temperature, respectively.

On the other hand, the obtained products (MoO₃-400, MoO₃-500, MoO₃-600, MoO₃-700, MoO₃-800, and MoO₃-900) were grinded thoroughly in an agate mortar to form a gas-sensing paste, respectively. Then, the paste was uniformly coated on the alumina ceramic tube in turn, and annealed in air at 120 ºC for 2 h. Here, the gas response magnitude of the sensor is defined as S = R_a/R_g, where R_a and R_g are the resistance in air and in the detected gas, respectively. Additionally, the response time and the recovery time were expected to be the minimum time required for the gas sensor output to reach 90% of its saturation after the gas was applied or shut off from the chamber.

2.3 Characterizations

The morphology of the products was investigated by a field emission scanning electron microscope (FESEM, Zeiss Gemini 500). The microstructure of the samples was investigated using X-ray diffraction (XRD, Rigaku Smartlab). X-ray photoelectron spectroscopy (XPS, Termo Scientific Escalab 250xi) was measured to further confirm the surface element composition and chemical state. And the Gas sensing properties were measured by the gas sensing system of MA1.0 (Narui Electronics Co. Ltd., China).

Figure 1 shows the typical FESEM images of the as-prepared MoO₃ samples. Specifically, hierarchical flower-like samples were observed by high resolution SEM images of Fig. 1a-c, which are the samples of MoO₃-400, MoO₃-500, and MoO₃-600, respectively. As a whole, the profile of the three samples are almost same, the microspheres, which the average diameter is less than 1 µm, are constructed by numerous plate-like nanosheets, and the edge thicknesses are about 19 nm. These irregular nanospheres are interconnected each other, facilitating electron transport and ethanol diffusion. After annealing, the hierarchical flower-like morphology was vanished. On the contrary, a lot of nanosheets were synthesized with increased thickness. Interestingly, the nanosheet thickness of sample MoO₃-600 become larger than that of MoO₃-400 and MoO₃-500, due to the growth of the MoO₃ crystalline grain at high temperature. In addition, it can be clearly observed that the voids enclosed by numerous primary ultrathin nanosheets with clear texture. Concretely, the diameter of nanoflowers derived from MoO₃ calcined in 400 ºC is about 0.3 µm, the sample calcined in 500 ºC is about 0.5 µm, the sample calcined in 600 ºC is about 4 µm. Figure 1d-f show the nanostructures of MoO₃ annealed between 700 and 900 ºC. Compared with the samples annealed at lower temperature, the MoO₃ annealed between 700 and 900 ºC exhibit the morphology of nanosheets, which represent higher crystallization. What’s more, the thickness of nanosheets is rising with the increase of annealing temperature. The thickness of nanosheets derived from the sample annealed at 700 ºC is 0.031 µm, the sample annealed at 800 ºC is 0.145 µm, and the sample annealed at 900 ºC is 1.690 µm. In terms of crystal growth, almost every point on the unpolished surface of a crystal can be filled with atoms to become the point where the crystal grows. The nanoflowers we obtained above, which has rougher surface than nanosheets, each point on the surface can be filled by atoms so as to becoming smooth and flush through supplying energy by calcining in high temperature. Certainly, as for the smooth surfaces, their consistent growth needs to be thermally activated [32]. Consequently, the samples obtained with 700–900 ºC can grow thicker with the annealing temperature increasing due to the more power and thermal provided.

To the best of our knowledge, the crystallinity, electronic structure and phase stability were strongly influenced by the calcination temperature and composition of the metal oxide semiconductor materials, especially the nanocomposites. Figure 2a shows the XRD patterns of MoO₃ samples which were calcined at different temperature. Evidently, the diffraction peaks of all the samples are consistent with the orthorhombic MoO₃ (JCPDS 05-0508). The intensity peaks at 2θ = 12.8, 25.7, and 39.1 corresponding to (020), (110), (040), (021), and (060) planes, respectively. This indicates that the sample grows with intense preferential orientation of (110). No other diffraction peaks are observed, which confirm that MoO₃ samples with relatively high crystal purity. Interestingly, the peak intensity increases with the annealing temperature from 400 to 900 ºC, which attributes to the good crystalline at high calcined temperature. On the other hand, the intensities of the peaks were gradually increased with the increase of annealing temperature. It indicates that the crystallinity of the samples was significantly improved via increasing annealing temperature. For example, the intensity of the peak (040) of MoO₃-900 is more than three times as compared with that of MoO₃-400.

On the basis of the above analysis, the chemical ingredient and the valence state of the elements in the MoO₃-600 nanosheets were analyzed via XPS. The corresponding results are shown in Fig. 2b and c. The Mo spectrum in Fig. 2b displays two ?? peaks located at 232.7and 235.8 eV, ascribe to Mo 3d_5/2 and Mo 3d_3/2, respectively, indicating that the chemical state of Mo element is present as Mo⁶⁺ in MoO₃-600. Further, the energy separation of two peaks is 3.2 eV, which indicates the successful fabrication of MoO₃ [30]. The peak of O 1s can be deconvoluted into two independent oxygen species at 529.8 and 531.4 eV (Fig. 2c). The peak at 529.8 eV in the O 1s curve can be attributed to the oxygen ions in the crystal lattice that is lattice oxygen O_lattice (O²⁻) and surface adsorbed oxygen O_ads. (e.g., O⁻) [33]. While the other peak at 531.4 eV were assigned to the oxygen ions species such as O⁻, O²⁻, and O₂⁻. Compared to the lattice oxygen, the absorbed O_x⁻ are active to ethanol, so they play a key role in enhancing the sensing performance [34, 35].

In order to investigate the optimum working temperature of different MoO₃ samples annealed at various temperature from 50 to 350 ºC to 10 ppm of ethanol, as shown in Fig. 3. Evidently, all the sensor’s response increase firstly before 200 ºC, and then decrease drastically with the increase of operation temperature further. Among them, the MoO₃-600 sensor exhibits the maximum response of 8.06 towards 100 ppm ethanol at 200 ºC, which is three times higher than those of MoO₃-400 and MoO₃-900, respectively. Compared with the MoO₃-600, the response values of MoO₃-400, MoO₃-500, MoO₃-700, MoO₃-800 and MoO₃-900 are 3.18, 5.34, 5.81 and 4.50 at 200 ℃, respectively. All in all, among all the sensors, the response of MoO₃-600 based sensor increases faster than that of others devices such as MoO₃-400, MoO₃-500, MoO₃-700, MoO₃-800 and MoO₃-900. These demonstrate that the nanostructure and annealing temperature of MoO₃ have a considerable effect on the device’s response, and inclination of response increases significantly and then gradually decreases. A suitable working temperature is indispensable in that ample thermal energy is a necessary prerequisite to overcome the chemical barrier of gas and the activation barrier of surface reaction. Besides, when the working temperature is further increased, the gas desorption rate is higher than adsorption rate, which is unfavorable to the response.

Figure 4a gives the dynamic response and recovery characteristics of the MoO₃-600 based sensor to different alcohol concentrations from 5 to 500 ppm CH₃CH₂OH at 200 ºC. Obviously, as the ethanol concentration increases, the response of the MoO₃-600 sensor climbs continually, thereafter, the response approaches the saturation value when the CH₃CH₂OH concentration overpass 500 ppm, see Fig. 4b. The similar results have been reported by other literature [35, 36]. It can be explained that more ethanol molecules can be physically or chemically adsorbed on the MoO₃-600 nanosheets, and speeding up the surface reaction rate with the chemisorbed oxygen species such as O⁻ and O₂⁻ [30, 36]. Additionally, according to the sensing mechanism of MoO₃, the increase of crystallization has an irreplaceable influence on its sensing properties [30, 36]. On the other hand, the limit of detection (LoD) of ethanol was evaluated by the method of linear extrapolation, specifically, the response sensitivity is a function of ethanol concentration (the inset of Fig. 4b). The detailed calculating formula of the LoD is: LoD = 3 × (Standard Deviation/Slope), from which the ultra-low ethanol detection concentration is 125 ppb for the MoO₃ sensor. Figure 4c shows a typical repeatability performance of the MoO₃ based sensor toward 100 ppm ethanol at 200 ºC, which exhibits its superb stability and repeatability. Moreover, the response time (τ_res) and recovery time (τ_recov) are examined and the results indicate that the MoO₃-600 sensor exhibits a very quick response and recovery properties to ethanol (Fig. 4d). Figure 4d gives the τ_res and τ_recov of the MoO₃-600 sensor toward 100 ppm ethanol, which are 7 s and 26 s, respectively.

From the aspect of practical applications, selectivity is another very important characteristics of the gas sensor. Herein, the sensing properties of MoO₃ nanosheets sensor to other various VOCs, for example, benzene, isopropanol, chloroform, acetic acid, methanol and acetone were evaluated. The selective property of the MoO₃-600 sensor towards 100 ppm of the above gas at 200 ºC is shown in Fig. 5a. Clearly, the maximum gas response value of MoO₃ toward 100 ppm alcohol is 8.06, which is evidently larger than those of other gases. Specifically, the responses to benzene, isopropanol, chloroform, acetic acid, methanol and acetone are 0.23, 1.47, 1.47, 1.57, 1.74 and 2.31, respectively. Therefore, the sensitivity of the MoO₃-600 towards ethanol is much higher than that of other VOCs, indicating that it has an excellent selectivity to ethanol.

The sensing mechanism of the MoO₃-600 to ethanol can be illustrated by surface conduction modulation model. According to the literature [16, 22], the adsorption and desorption of target gas molecules from the surface of the MoO₃-600 could regulate the electrical resistance of gas sensor. When the MoO₃-600 is exposed to fresh air, the oxygen molecules (O₂) will capture conductive band electrons (e^-1) to form chemisorbed oxygen ions species (O^- and O₂^-). This process will form a depletion layer on its surface region of sensing material, which causes the device resistance increase. When the MoO₃-600 sensor was exposed to ethanol gas, the ethanol molecules can react with the oxygen species O^- and O₂^-, resulting in the release of trapped electrons back to the conduction band, thereby significantly reducing the sensor resistance. This reaction processes can be expressed as Equations (1) and (2) [37, 38]:

CH₃CH₂OH_(gas) + 6O₂⁻_(ads) → 2CO_2(gas) + 3H₂O_(gas) + 12e⁻ (1)

CH₃CH₂OH_(gas) + 6O⁻_(ads) → 2CO_2(gas) + 3H₂O_(gas) + 6e⁻ (2)

In conclusion, various MoO₃ nanomaterials were successfully prepared by hydrothermal and calcined processes. The nanostructure morphology and crystal quality of MoO₃ have temperature-depend relationships. According to the results, the MoO₃ morphology can be manipulated by annealing temperature from nanoflowers, nanosheets to nanorods. In addition, the ethanol sensing performances were carefully investigated by MoO₃ samples. It is found that the MoO₃-600 has an excellent sensing performance duo to the combination of degree of crystallinity and nanostructure.

Acknowledgements

This work was financially supporting from the National Natural Science Foundation of China (Grant No. 51227804). Projects of Science and Technology Commission of Shanghai Municipality Grant Nos. (19ZR1473800, 14DZ2260800). This work was also funded by the Postdoctoral Scientific Research Foundation of Qingdao. National College Students Innovation and Entrepreneurship Training Program of China (No. G201811065023). The authors would like to thank the Chemical Experimental Teaching Center of Qingdao University for the Measurement Support, and Kehui Han from Shiyanjia Lab (www.shiyanjia.com) for the XRD analysis.

Conflict of interest

The authors declare that they have no competing financial interest.

X. Gao, T. Zhang, An overview: Facet-dependent metal oxide semiconductor gas sensors. Sensor Actuat B-chem 277, 604–633 (2018)
Z. Wang, P. Nayak, A. Jesus, H. Alshareef, Recent Developments in p-Type Oxide Semiconductor Materials and Devices. Adv Mater 28, 3831–3892 (2016)
X. Qian, X. Liu, B. Wan, Z. Yang, F. Li, J. Lu, G. Hu, C. Pan, Z. Wang, In₂O₃ Nanowire Field-Effect Transistors with Sub-60 mV/dec Subthreshold Swing Stemming from Negative Capacitance and Their Logic Applications. ACS Nano 12, 9608–9616 (2018)
S. Li, Y. Zhang, W. Yang, H. Liu, X. Fang, 2D perovskite Sr₂Nb₃O₁₀ for high-performance UV photodetectors. Adv Mater 32, 1905443 (2020)
Y. Zhang, X. Zhao, J. Chen, S. Li, W. Yang, X. Fang, Self-polarized BaTiO₃ for greatly enhanced performance of ZnO UV photodetector by regulating the distribution of electron concentration. Adv. Funct. Mater. 30, 1907650 (2020)
J. Niu, C. Zeng, H. Peng, X. Lin, P. Sathishkumar, Y. Cai, Formation of N-Doped Carbon-Coated ZnO/ZnCo₂O₄/ CuCo₂O₄ Derived from a Polymetallic Metal–Organic Framework: Toward High-Rate and Long-Cycle-Life Lithium Storage. Small 13(47), 1702150 (2017)
C. Zhao, D. Zhong, D. Zhong, L. Liu, Y. Yang, H. Shi, L. Peng, Z. Zhang, Strengthened Complementary Metal–Oxide–Semiconductor Logic for Small-Band-Gap Semiconductor-Based High-Performance and Low-Power Application. ACS Nano 14(11), 15267–15275 (2020)
C. Su, L. Zhang, Y. Han, C. Ren, M. Zeng, Z. Zhou, Y. Su, N. Hu, H. Wei, Z. Yang, Controllable synthesis of heterostructured CuO–NiO nanotubes and their synergistic effect for glycol gas sensing. Sensor Actuat B-chem 304, 127347 (2020)
S. Fields, S. Smith, P. Ryan, S. Jaszewski, I. Brummel, A. Salanova, G. Esteves, S. Wolfley, M. Henry, P. Davids, J. Ihlefeld, Phase-Exchange-Driven Wake-Up and Fatigue in Ferroelectric Hafnium Zirconium Oxide Films. ACS Appl Mater Inter 12, 26577–26585 (2020)
Z. Long, X. Xu, W. Yang, M. Hu, D. Shtansky, D. Golberg, X. Fang, Cross-bar SnO₂-NiO nanofiber-arrays-based transparent photodetectors with high detectivity. Adv Electron Mater 6, 1901048 (2020)
A. Bathinapatla, S. Kanchi, M. Sabela, Y. Ling, K. Bisetty, Inamuddin, Experimental and Computational Studies of a Laccase Immobilized ZnONPs/GO-Based Electrochemical Enzymatic Biosensor for the Detection of Sucralose in Food Samples. Food Anal Method 13, 2014–2027 (2020)
T. Inamuddin, Rangreez, A. Asiri, Fabrication and optimization of Cu(II) ion selective membrane electrode. J Water Chem Techno 39, 220–227 (2020)
S. Shen, X. Zhang, X. Cheng, Y. Xu, S. Gao, H. Zhao, X. Zhou, L. Huo, Oxygen-Vacancy-Enriched Porous α–MoO₃ Nanosheets for Trimethylamine Sensing. ACS Appl Nano Mater 2, 8016–8026 (2019)
S. Zhou, Q. Lu, M. Chen, H. Bo Li, Wei, B. Zi, J. Zeng, Y. Zhang, J. Zhang, Z. Zhu, Q. Liu, Platinum-Supported Cerium-Doped Indium Oxide for Highly Sensitive Triethylamine Gas Sensing with Good Antihumidity. ACS Appl Mater Inter 12(38), 42962–42970 (2020)
L. Zheng, F. Teng, X. Ye, H. Zheng, X. Fang, Photo/electrochemical applications of metal sulfide/TiO₂ heterostructures. Adv Energy Mater 10, 1902355 (2020)
P. Wang, S. Wang, Y. Kang, Z. Sun, X. Wang, Y. Meng, M. Hong, W. Xie, Cauliflower-shaped Bi₂O₃/ZnO heterojunction with superior sensing performance towards ethanol. J. Alloy. Compd. 854, 157152 (2021)
N. Graddage, J. Ouyang, J. Lu, T. Chu, Y. Zhang, Z. Li, X. Wu, P. Malenfant, Y. Tao, Near-Infrared-II Photodetectors Based on Silver Selenide Quantum Dots on Mesoporous TiO₂ Scaffolds. ACS Appl Mater Inter (2020). https://dx.doi.org/10.1021/acsanm.0c02686
X. Zhuang, S. Patel, C. Zhang, B. Wang, Y. Chen, H. Liu, V. Dravid, J. Yu, Y. Hu, W. Huang, A. Facchetti, T. Marks, Frequency-Agile Low-Temperature Solution-Processed Alumina Dielectrics for Inorganic and Organic Electronics Enhanced by Fluoride Doping. J. Am. Chem. Soc. 142(28), 12440–12452 (2020)
R. Medhi, M. Marquez, T. Lee, Visible-Light-Active Doped Metal Oxide Nanoparticles: Review of their Synthesis, Properties, and Applications. ACS Appl Nano Mater 3, 6156–6185 (2020)
Q. Qian, Y. Li, Y. Liu, L. Yu, G. Zhang, Ambient Fast Synthesis and Active Sites Deciphering of Hierarchical Foam-Like Trimetal–Organic Framework Nanostructures as a Platform for Highly Efficient Oxygen Evolution Electrocatalysis. Adv Mater 31(23), 1901139 (2019)
T. Zhang, B. Huang, A. Elzatahry, A. Alghamdi, Q. Yue, Y. Deng, Synthesis of Podlike Magnetic Mesoporous Silica Nanochains for Use as Enzyme Support and Nanostirrer in Biocatalysis. ACS Appl Mater Inter 12, 17901–17908 (2020)
M. Lei, X. Zhou, Y. Zou, J. Ma, F. Alharthi, A. Alghamdi, X. Yang, Y. Deng, A facile construction of heterostructured ZnO/Co₃O₄ mesoporous spheres and superior acetone sensing performance. Chin Chem Lett (2020). https://doi.org/10.1016/j.cclet.2020.10.041
Y. Ren, Y. Zou, Y. Liu, X. Zhou, J. Ma, D. Zhao, G. Wei, Y. Ai, S. Xi, Y. Deng, Synthesis of orthogonally assembled 3D cross-stacked metal oxide semiconducting nanowires. Nat. Mater. 19(2), 203–211 (2020)
X. Zhao, C. Xiang, F. Zhang, F. Yao, R. Sheng, Q. Ding, W. Liu, H. Zhang, X. Zhou, Transformation from 3D Boron Organic Polymers to 1D Nanorod Arrays: Loading Highly Dispersed Nanometal for Green Catalysis. ACS Appl Mater Inter 11(46), 43214–43222 (2019)
N. Rani, S. Chahal, P. Kumar, A. Kumar, R. Shukla, S. Singh, MgO nanostructures at different annealing temperatures for d(0) ferromagnetism. Vacuum 179, 109539 (2020)
J. Hyunseok, Z. Chao, K. Xiao, S. Jaejung, D. Feng, C. Seungho, Homoepitaxial growth of ZnO nanostructures from bulk ZnO. J Colloid Interf Sci (2020). https://doi.org/10.1016/j.jcis.2020.10.078
W. Yin, J. Yang, K. Zhao, High Responsivity and External Quantum Efficiency Photodetectors Based on Solution-Processed Ni-Doped CuO Films. ACS Appl Mater Inter 12(10), 11797–11805 (2020)
F. Zhang, Y. Wang, L. Wang, J. Liu, H. Ge, B. Wang, X. Huang, X. Wang, Z. Chi, W. Xie, High performance In₂(MoO₄)₃@In₂O₃ nanocomposites gas sensor with long-term stability. J. Alloy. Compd. 805, 180–188 (2019)
L. Zhua, W. Zenga, Y. Lib, J. Yanga, Enhanced ethanol gas-sensing property based on hollow MoO₃ microcages. Physica E 106, 170–175 (2019)
Z. Tanga, X. Denga, Y. Zhanga, X. Guod, J. Yanga, C. Zhua, J. Fana, Y. Shia, B. Qinga, F. Fan, MoO₃ nanoflakes coupled reduced graphene oxide with enhanced ethanol sensing performance and mechanism. Sensor Actuat B-chem 297, 126730 (2019)
J. Hu, X. Wang, M. Zhang, Y. Sun, P. Li, W. Zhang, K. Lian, L. Chen, Y. Chen, Synthesis and characterization of flower-like MoO₃/In₂O₃ microstructures for highly sensitive ethanol detection. RSC Adv 7, 23478 (2017)
W. Xie, Z. Pang, Y. Zhao, F. Jiang, H. Yuan, H. Song, S. Han, Structural and optical properties of ε-phase tris(8-hydroxyquinoline) aluminum crystals prepared by using physical vapor deposition method. J. Cryst. Growth 404, 164–167 (2014)
X. Chen, S. Wang, C. Su, Y. Han, C. Zou, M. Zeng, N. Hu, Y. Su, Z. Zhou, Z. Yang, Two-dimensional Cd-doped porous Co₃O₄ nanosheets for enhanced room temperature NO₂ sensing performance. Sensor Actuat B-chem 305, 127393 (2020)
D. Wang, Y. Yin, P. Xu, F. Wang, P. Wang, J. Xu, X. Wang, X. Li, Catalytic-induced Sensing Effect of Triangular CeO₂ Nanoflakes for Enhanced BTEX Vapor Detection with Conventional ZnO Gas Sensors. J Mater Chem A 8, 11188–11194 (2020)
D. Wang, L. Deng, H. Cai, J. Yang, L. Bao, Y. Zhu, X. Wang, Bimetallic PtCu Nanocrystal Sensitization WO₃ Hollow Spheres for Highly Efficient 3-hydroxy-2-butanone Biomarker Detection. ACS Appl Mater Inter 12(16), 18904–18912 (2020)
X. Huang, Z. Chi, J. Liu, D. Li, X. Sun, C. Yan, Y. Wang, H. Li, X. Wang, W. Xie, Enhanced gas sensing performance based on p-NiS/n-In₂O₃ heterojunction nanocomposites. Sens. Actuators B 304, 127305 (2020)
K. Zhang, S. Qin, P. Tang, Y. Feng, D. Li, Ultra-sensitive ethanol gas sensors based on nanosheet-assembled hierarchical ZnO-In₂O₃ heterostructures. J. Hazard. Mater. 391, 122191 (2020)
D. Zhang, Y. Cao, J. Wu, X. Zhang, Tungsten trioxide nanoparticles decorated tungsten disulfide nanoheterojunction for highly sensitive ethanol gas sensing application. Appl Surf Sci 503, 144063 (2020)

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MoO3 Structures Transition from Nanoflowers to Nanorods and Their Sensing Performances

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Abstract

Figures

1. Introduction

2. Experimental Section

2.1 Materials

2.2 Fabrication of MoO₃ materials

2.3 Characterizations

3. Result And Discussion

4. Conclusion

Declarations

Acknowledgements

Conflict of interest

References

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Version 1

MoO3 Structures Transition from Nanoflowers to Nanorods and Their Sensing Performances

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Version 1

Abstract

Figures

1. Introduction

2. Experimental Section

2.1 Materials

2.2 Fabrication of MoO3 materials

2.3 Characterizations

3. Result And Discussion

4. Conclusion

Declarations

Acknowledgements

Conflict of interest

References

Status:

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2.2 Fabrication of MoO₃ materials