Hydrothermal Synthesis and Gas Sensing of Monoclinic MoO3 Nanosheets

Effects of different reaction parameters in the hydrothermal synthesis of molybdenum oxides (MoO3) were investigated and monoclinic (β-) MoO3 was prepared hydrothermally for the first time. Various temperatures (90/210 °C, and as a novelty 240 °C) and durations (3/6 h) were used. At 240 °C, cetyltrimethylammonium bromide (CTAB) and CrCl3 additives were also tested. Both the reaction temperatures and durations played a significant role in the formation of the products. At 90 °C, h-MoO3 was obtained, while at 240 °C the orthorhombic (α-) MoO3 formed with hexagonal rod-like and nanofibrous morphology, respectively. The phase transformation between these two phases was observed at 210 °C. At this temperature, the 3 h reaction time resulted in the mixture of h- and α-MoO3, but 6 h led to pure α-MoO3. With CTAB the product was bare o-MoO3, however, when CrCl3 was applied, pure metastable m-MoO3 formed with the well-crystallized nanosheet morphology. The gas sensing of the MoO3 polymorphs was tested to H2, which was the first such gas sensing study in the case of m-WO3. Monoclinic MoO3 was found to be more sensitive in H2 sensing than o-MoO3. This initial gas sensing study indicates that m-MoO3 has promising gas sensing properties and this MoO3 polymorph is promising to be studied in detail in the future.

[1]  M. Ritala,et al.  Photocatalytic and Gas Sensitive Multiwalled Carbon Nanotube/TiO2-ZnO and ZnO-TiO2 Composites Prepared by Atomic Layer Deposition , 2020, Nanomaterials.

[2]  P. V. Satyam,et al.  Optical band gap, local work function and field emission properties of MBE grown β-MoO3 nanoribbons , 2019, Applied Surface Science.

[3]  Qianxin Zhang,et al.  Construction of carbon dots modified MoO3/g-C3N4 Z-scheme photocatalyst with enhanced visible-light photocatalytic activity for the degradation of tetracycline , 2018, Applied Catalysis B: Environmental.

[4]  K. Faungnawakij,et al.  Deoxygenation of oleic acid under an inert atmosphere using molybdenum oxide-based catalysts , 2018, Energy Conversion and Management.

[5]  D. Bahnemann,et al.  Harvesting visible light with MoO3 nanorods modified by Fe(iii) nanoclusters for effective photocatalytic degradation of organic pollutants. , 2018, Physical chemistry chemical physics : PCCP.

[6]  H. Afify,et al.  Hydrothermal synthesis and influence of later heat treatment on the structural evolution, optical and electrical properties of nanostructured α-MoO3 single crystals , 2017 .

[7]  H. Nagabhushana,et al.  MoO3 nanostructures from EGCG assisted sonochemical route: Evaluation of its application towards forensic and photocatalysis , 2017 .

[8]  R. Datta,et al.  Molybdenum Oxides – From Fundamentals to Functionality , 2017, Advanced materials.

[9]  Hashitha M. M. Munasinghe Arachchige,et al.  Gas Sensing Properties of MoO3 , 2017 .

[10]  I. Parkin,et al.  Phase and morphological control of MoO3-x nanostructures for efficient cancer theragnosis therapy. , 2017, Nanoscale.

[11]  A. Moholkar,et al.  Orthorhombic MoO3 nanobelts based NO2 gas sensor , 2017 .

[12]  X. Jiao,et al.  Novel Fabrication and Enhanced Photocatalytic MB Degradation of Hierarchical Porous Monoliths of MoO3 Nanoplates , 2017, Scientific Reports.

[13]  Jian Li,et al.  h-MoO3 microrods grown on wood substrates through a low-temperature hydrothermal route and their optical properties , 2017, Journal of Materials Science: Materials in Electronics.

[14]  Peng Song,et al.  Au nanoparticles modified MoO3 nanosheets with their enhanced properties for gas sensing , 2016 .

[15]  T. Mahalingam,et al.  Photoelectrochemical study of MoO3 assorted morphology films formed by thermal evaporation , 2016 .

[16]  K. Chou,et al.  Preparation of Ultrafine β-MoO3 from Industrial Grade MoO3 Powder by the Method of Sublimation , 2016 .

[17]  Yan Zhao,et al.  Synthesis of α-MoO3 nanobelts with preferred orientation and good photochromic performance , 2016 .

[18]  T. Thongtem,et al.  Influence of Gd dopant on photocatalytic properties of MoO3 nanobelts , 2016 .

[19]  V. V. Kumar,et al.  Synthesis of α-MoO3 nanoplates using organic aliphatic acids and investigation of sunlight enhanced photodegradation of organic dyes , 2016 .

[20]  A. C. Bose,et al.  Hydrothermally Synthesized h-MoO3 and α-MoO3 Nanocrystals: New Findings on Crystal-Structure-Dependent Charge Transport , 2016 .

[21]  Shuang Yang,et al.  Hydrothermal synthesis of h -MoO 3 microrods and their gas sensing properties to ethanol , 2015 .

[22]  T. Pham,et al.  Facile method for synthesis of nanosized β–MoO3 and their catalytic behavior for selective oxidation of methanol to formaldehyde , 2015 .

[23]  Wojtek Wlodarski,et al.  Two dimensional α-MoO3 nanoflakes obtained using solvent-assisted grinding and sonication method: Application for H2 gas sensing , 2014 .

[24]  V. Pillai,et al.  Hydrogen and ethanol sensing properties of molybdenum oxide nanorods based thin films: Effect of electrode metallization and humid ambience , 2013 .

[25]  Ling-Ling Xie,et al.  Hydrothermal synthesis of hexagonal MoO3 and its reversible electrochemical behavior as a cathode for Li-ion batteries , 2013, Electronic Materials Letters.

[26]  A. C. Bose,et al.  Preparation of h-MoO3 and α-MoO3 nanocrystals: comparative study on photocatalytic degradation of methylene blue under visible light irradiation. , 2013, Physical chemistry chemical physics : PCCP.

[27]  C. Liu,et al.  Ultrasonic synthesis of MoO3 nanorods and their gas sensing properties , 2012 .

[28]  M. Leskelä,et al.  WO3 photocatalysts: Influence of structure and composition , 2012 .

[29]  M. Rodriguez-Garcia,et al.  Gas sensing properties of nanostructured MoO3 thin films prepared by spray pyrolysis , 2012 .

[30]  J. S. Lee,et al.  Free-polymer controlling morphology of α-MoO3 nanobelts by a facile hydrothermal synthesis, their electrochemistry for hydrogen evolution reactions and optical properties , 2012 .

[31]  H. Fan,et al.  Hydrothermal synthesis of single crystal MoO3 nanobelts and their electrochemical properties as cathode electrode materials for rechargeable lithium batteries , 2012 .

[32]  N. Phuc,et al.  Soft chemical transformation of α-MoO3 to β-MoO3 as a catalyst for vapor-phase oxidation of methanol , 2011 .

[33]  A. C. Bose,et al.  Hydrothermal synthesis of hexagonal and orthorhombic MoO3 nanoparticles , 2011 .

[34]  Delphic Chen,et al.  Post-deposition annealing control of phase and texture for the sputtered MoO3 films , 2011 .

[35]  J. Madarász,et al.  Gas sensing selectivity of hexagonal and monoclinic WO3 to H2S , 2010 .

[36]  G. Muralidharan,et al.  Optical, structural and electrochromic studies of molybdenum oxide thin films with nanorod structure , 2010 .

[37]  A. Szabó,et al.  Stability and Controlled Composition of Hexagonal WO3 , 2008 .

[38]  V. S. Sapkal,et al.  Structural and gas sensing properties of nanocrystalline TiO2:WO3-based hydrogen sensors , 2006 .

[39]  A. Bouzidi,et al.  Effect of substrate temperature on the structural and optical properties of MoO3 thin films prepared by spray pyrolysis technique , 2003 .

[40]  C. Julien,et al.  Micro-Raman characterization of WO3 and MoO3 thin films obtained by pulsed laser irradiation , 1998 .

[41]  E. Teller,et al.  ADSORPTION OF GASES IN MULTIMOLECULAR LAYERS , 1938 .

[42]  Bo-Mi Hwang,et al.  MoO3 Nanostructured Electrodes Prepared via Hydrothermal Process for Lithium Ion Batteries , 2015, International Journal of Electrochemical Science.