Synthesis of Microporous Mo2C-W2C Binary Carbides by Thermal Decomposition of Molybdenum-Tungsten Blues.

Natalia Gavrilova,Maria Myachina,Victor Dyakonov,Victor Nazarov,Valery Skudin

doi:10.3390/nano10122428

Natalia Gavrilova, Maria Myachina + Show 3 more

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https://doi.org/10.3390/nano10122428

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Abstract

Molybdenum and tungsten carbides are perspective catalytic systems. Their activity in many reactions is comparable to the activity of platinum group metals. The development of the synthesis method for of highly dispersed binary molybdenum and tungsten carbides is an important task. Dispersions of molybdenum-tungsten blue were used as a precursor for synthesis of binary molybdenum and tungsten carbides. The synthesis of carbides was carried out by thermal decomposition of molybdenum-tungsten blue xerogels in an inert atmosphere. The binary carbides were characterized by XRD, TGA, SEM and nitrogen adsorption. The influence of the molar ratio reducing agent/Me [R]/[ΣMe], molar ratio molybdenum/tungsten [Mo]/[W] on phase composition, and morphology and porous structure of binary carbides was investigated. Samples of binary molybdenum and tungsten carbides with a highly developed porous structure and a specific surface area were synthesized.

Highlights

Molybdenum and tungsten carbides are compounds with high electrical conductivity, thermal stability and mechanical strength [1]
Tungsten carbide is characterized by a higher oxophilicity, and when it is incorporated into the structure of molybdenum carbide, the metallic properties of molybdenum carbide change [15]
The presence of a synergistic effect in binary carbide Mo2C-W2C was confirmed for many catalytic processes including hydrogen evolution reaction (HER), dry reforming of methane, and conversion of aromatic hydrocarbons [10,16,17]

Summary

Introduction

Molybdenum and tungsten carbides are compounds with high electrical conductivity, thermal stability and mechanical strength [1]. Molybdenum and tungsten carbides possess a high catalytic activity in many catalytic processes. They are of great interest as catalysts for hydrogenation processes and natural gas conversion processes, as well as for use in fuel cells [2,3,4,5]. Activity of molybdenum and tungsten carbide is comparable to the activity of noble metals. An increase in catalytic activity can be achieved if a carbide of a metal similar in properties to molybdenum (for example, tungsten carbide [13,14]) is introduced into the crystal lattice of a highly active molybdenum carbide. The presence of a synergistic effect in binary carbide Mo2C-W2C was confirmed for many catalytic processes including hydrogen evolution reaction (HER), dry reforming of methane, and conversion of aromatic hydrocarbons [10,16,17]

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