中国科学院大连化物所孙剑团队报道了反应诱导的不饱和氧化钼制备高活性的CO₂转化催化剂。相关研究成果发表在2024年9月9日出版的《自然—化学》。

可持续的二氧化碳转化对于遏制过量排放至关重要。碳化钼催化剂在催化二氧化碳转化方面表现出优异的性能，但苛刻的渗碳合成和较差的稳定性使研究具有挑战性。

该文中，不饱和氧化钼（Mo₁₇O₄₇）在不进行渗碳预处理的情况下，对逆水煤气变换反应表现出很高的活性，并在600°C下保持稳定2000小时。火焰喷雾热解合成和Ir助催化剂促进了Mo₁₇O₄₇的形成及其在反应过程中的原位渗碳。

立方α-MoC与表面不饱和碳化钼（MoOxCy）的反应诱导的反应是催化的关键活性位点。机理研究表明，CO₂中的C原子插入两个Mo原子之间的空位中，并通过碳循环途径从碳氧化物中取出另一个C原子来再生空位，从而释放CO。

具有不饱和碳氧化物活性位点的钼催化剂的设计，为高温应用提供了新的领域，并为二氧化碳转化提供了替代途径。

附：英文原文

Title: Reaction-induced unsaturated Mo oxycarbides afford highly active CO2 conversion catalysts

Author: Sun, Xingtao, Yu, Jiafeng, Zada, Habib, Han, Yu, Zhang, Ling, Chen, Huaican, Yin, Wen, Sun, Jian

Issue&Volume: 2024-09-09

Abstract: Sustainable CO2 conversion is crucial in curbing excess emissions. Molybdenum carbide catalysts have demonstrated excellent performances for catalytic CO2 conversion, but harsh carburization syntheses and poor stabilities make studies challenging. Here an unsaturated Mo oxide (Mo17O47) shows a high activity for the reverse water–gas shift reaction, without carburization pretreatments, and remains stable for 2,000h at 600°C. Flame spray pyrolysis synthesis and Ir promoter facilitate the formation of Mo17O47 and its in situ carburization during reaction. The reaction-induced cubic α-MoC with unsaturated Mo oxycarbide (MoOxCy) on the surface serves as the active sites that are crucial for catalysis. Mechanistic studies indicate that the C atom in CO2 inserts itself in the vacancy between two Mo atoms, and releases CO by taking another C atom from the oxycarbide to regenerate the vacancy, following a carbon cycle pathway. The design of Mo catalysts with unsaturated oxycarbide active sites affords new territory for high-temperature applications and provides alternative pathways for CO2 conversion.

DOI: 10.1038/s41557-024-01628-4

Source: https://www.nature.com/articles/s41557-024-01628-4