The versatile family of molybdenum oxides: synthesis, properties, and recent applications

Abstract

The family of molybdenum oxides has numerous advantages that make them strong candidates for high-value research and various commercial applications. The variation of their multiple oxidation states allows their existence in a wide range of compositions and morphologies that converts them into highly versatile and tunable materials for incorporation into energy, electronics, optical, and biological systems. In this review, a survey is presented of the most general properties of molybdenum oxides including the crystalline structures and the physical properties, with emphasis on present issues and challenging scientific and technological aspects. A section is devoted to the thermodynamical properties and the most common preparation techniques. Then, recent applications are described, including photodetectors, thermoelectric devices, solar cells, photo-thermal therapies, gas sensors, and energy storage.

α-MoO3 Micro- and Nanoparticles as Catalysts for Biofuel Production

“…10−13 MoO 3 presents different polymorphic forms, such as hexagonal h-MoO 3 , monoclinic β-MoO 3 , and orthorhombic α-MoO 3 . 10,14 The orthorhombic structure form of α-MoO 3 has already been tested apart for the methylic transesterification or esterification of different oils but usually when it is deposited on different catalytic supports or when modified by dopants. 5,8,9,15−20 Few studies in the literature highlight biofuel production by polycrystalline α-MoO 3 catalysts prepared by hydrothermal and combustion methods.…”

“…Solid acid catalysts have been considered a promising strategy to simultaneously promote esterification and transesterification reactions without triggering saponification processes, reducing the production of harmful substances and toxic residues . Particularly, molybdenum trioxide (MoO 3 ) has shown an excellent catalytic conversion rate in esterification and transesterification reactions to produce biodiesel due to its interesting physical and chemical characteristics. ,− In addition, MoO 3 is widely used to prepare sensors, solid-state fuel cells, optical instruments, photocatalysts, and others. − MoO 3 presents different polymorphic forms, such as hexagonal h-MoO 3 , monoclinic β-MoO 3 , and orthorhombic α-MoO 3 . , The orthorhombic structure form of α-MoO 3 has already been tested apart for the methylic transesterification or esterification of different oils but usually when it is deposited on different catalytic supports or when modified by dopants. ,,,− Few studies in the literature highlight biofuel production by polycrystalline α-MoO 3 catalysts prepared by hydrothermal and combustion methods. − Despite these works, the authors did not evaluate the importance of the crystal structure, crystal orientation, and ionic defects and their relationship with the catalytic properties of α-MoO 3 .…”

The novel Co-doped MoO3 microwave absorber prepared by heat treatment

“…Molybdenum trioxide (MoO 3 ) presents potential as MAM [11]. The conductivity and magnetic moment of α-MoO 3 can be improved by doping ions [12,13].…”

Carbon-Assisted Isothermal Close Space Vapor Transport Growth of Mo4O11 and MoO2 Micro/Nanostructures by in Situ Formation of the Mo(CO)6 Transport Agent

“…These and other less studied phases such as hexagonal (h-MoO 3 ), monoclinic (β-MoO 3 ), high-pressure/high-temperature monoclinic modification (ε-MoO 3 ), and tetragonal T-MoO 2 have been prepared also by using a variety of chemical or physical methods including, among others, Chemical Vapor Deposition, Thermal decomposition of organic complexes, Solvothermal Method, Electron Beam Deposition, Spray Pyrolysis, and Electrodeposition . General properties, growth methods, and applications of molybdenum oxides have been reviewed recently. , In particular, Mo 4 O 11 has been prepared by Solid State Sintering, and Chemical Vapor Transport in a close quartz ampule with I 2 as the transport agent . Heating of (NH 4 ) 8 Mo 10 O 34 precursor has been used for the preparation of MoO 2 /Mo 4 O 11 composites while mixed orthorhombic/monoclinic Mo 4 O 11 rods have been grown by Hot Filament Metal Oxide Vapor Deposition …”