The synthesis of molybdenum carbide catalysts needs a high temperature, in which the passivation by an oxygen-containing atmosphere is inevitable. It is challenging to develop a new route to prepare molybdenum carbide at a low temperature in order to increase the density of surface active sites.

Recently, a research group led by Prof. BAO Xinhe and FU Qiang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) revealed an In-situ dynamic carburization method to synthesize molybdenum carbide in reverse water-gas shift (RWGS) reaction.

This work was published in Angewandte Chemie International Edition on Aug. 15.

In-situ carburization process of the Mo-based catalyst during RWGS reaction for unprecedented high CO formation

In this work, the researchers find that introducing intercalated hydrogen into MoO3 to form HxMoOy promotes its reduction, which can be in-situ carburized at 500 ℃ in the RWGS reaction. The carburization to form highly active molybdenum carbide exhibits enhanced RWGS reaction activity.

The research results indicate that the surface properties of catalysts and the reaction microenvironment affect the carbonization process. A low O/Mo ratio of the catalyst is more favorable to carbonization. Meanwhile, a high CO2 conversion rate, i.e., a high CO partial pressure, is more conducive to carbonization.

Carbonization significantly enhances CO2 adsorption and activation, thereby improving RWGS reaction activity. This in-situ carburization strategy provides insight into the synthesis of metal carbides in a carbon-containing reaction atmosphere.

"The structural evolution of the catalyst plays an important role during the reaction, which can be used to enhance the catalytic performance by the rational control strategy," said Prof. FU.

This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, and the Photon Science Center for Carbon Neutrality. (Text/Image by DU Xiangze)