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[Display omitted] • A new kinetic model describing the methanol reduction of metal oxides has been proposed. • The effects of temperature on the particle's morphologies and size are illustrated. • The reduction mechanisms and reaction pathway were investigated based on thermodynamic and thermogravimetric analysis. Alcohols, represented by methanol, have received attention as a new type of reducing agent in various fields, including carbide synthesis, surface carburization etc. In order to clarify the reduction routes, reaction mechanisms and influencing factors on the morphology of the products during the methanol dominated reduction process, this work examined the preparation of molybdenum hemicarbide by reducing and carbonizing MoO 3 with methanol. We used a combination of thermodynamic calculations, thermogravimetric analysis and XRD to clarify the reduction path of MoO 3 at different temperatures, and characterized the morphology evolution of the product using SEM. Furthermore, a novel kinetic mathematical model was proposed to account for the intricate reaction involving methanol and multivalent oxide, which incorporated numerous parameters with practical physical significance, enhancing its predictive precision. In summary, our findings provide valuable insights into thermodynamics, kinetics, and experimental aspects of reactions involving methanol, offering guidance for controlled carbide particle synthesis. [ABSTRACT FROM AUTHOR]

• Shape-controlled synthesis of W particles via salt-assisted reduction was proposed. • Large powders disappeared and were degraded under the influence of Y(NO 3) 3. • Temperature and additive greatly affected the morphology and size of W particles. • The added salt improved the crystallization of particles. • The reaction mechanism was discussed as well. Tungsten, one of the refractory metals, has lots of excellent properties, making tungsten powders become a choice of raw material for many applications. This work reported a simple method (the salt-assisted hydrogen reduction of WO 3 powders) for preparing tungsten powders with desired morphologies and size. By adjusting the amount of additive (Y(NO 3) 3) and reduction temperature, metallic tungsten particles with different morphologies and size were obtained. It was found that both temperature and additive had apparent effects on the morphology and size of metallic W particles, and the large parallelepiped-shaped powders disappeared and large irregular blocky-shaped powders were degraded under the influence of additive. With the increase of temperature and amount of salt, particles became more dispersed and the size increased at higher temperatures, and the shape of particles was changed from spherical to polyhedral as well. On the contrary, the size of sub-particles became smaller as increasing amount of Y(NO 3) 3 at lower temperatures. Based on the results, the reaction and refining mechanisms for preparing tungsten were proposed as well. [ABSTRACT FROM AUTHOR]

Titanium oxycarbide can be used as a soluble anode to produce sponge titanium in USTB or MER molten salt electrolysis process. However, the key factor of these two processes is to prepare oxycarbide with appropriate C/O ratio and at a low cost as well. This work reported a simple method of preparing titanium oxycarbide from TiO 2 in C-H 2 system. Based on the prediction of thermodynamic calculations, titanium oxycarbide was prepared successfully at 1400 °C with the molar ratio of TiO 2 to carbon exceeding 1:2, and the ideal electrolytic anode (TiC 0.5 O 0.5) was produced at 1400 °C (with a ratio of 1:3 of TiO 2 to carbon). Number of parameters (carbon content, temperature, sample's mass, additive (Fe element), and with ball milling treatment) were considered and discussed in the current study. Furthermore, this method can reduce not only the reaction temperature and time, but also the emission of carbon dioxide. • Titanium Oxycarbide with controllable C/O ratio was produced by considering number of parameters in TiO 2 -C-H 2 System. • The ideal electrolytic anode (TiC 0.5 O 0.5) can be produced when the ratio of TiO 2 to carbon is 1:3 at 1400 °C. • The reaction temperature, the usage and emission of carbon were reduced by introducing clean energy (H 2). • The reaction mechanism was discussed as well. [ABSTRACT FROM AUTHOR]

Tungsten carbides, which can be widely used as cutting and drilling tools, chemical catalysts and aerospace coatings, have attracted widespread attentions. The present work reported a simple method to prepare tungsten carbides by using WO 2 as the raw materials and CO as the reduction and carbonization agent. It was found that at lower and moderate temperatures, all the final product was WC, while at higher temperatures, the final products were W 2 C or W. The reduction and carbonization mechanism was also studied theoretically and experimentally. WO 2 was reduced and carburized to WC in one step at lower temperatures; WO 2 was first reduced and carburized to W 2 C and then to WC at moderate temperatures; while at higher temperatures, WO 2 was first reduced to metallic W and then carbonized to WC or W 2 C, but with the temperature increasing, the carbonization became difficult and required much higher CO content. [ABSTRACT FROM AUTHOR]