Understanding and Tuning the Effects of HO on Catalytic CO and CO Hydrogenation.

Catalytic CO (CO and CO) hydrogenation to valued chemicals is one of the promising approaches to address challenges in energy, environment, and climate change. HO is an inevitable side product in these reactions, where its existence and effect are often ignored. In fact, HO significantly influences the catalytic active centers, reaction mechanism, and catalytic performance, preventing us from a definitive and deep understanding on the structure-performance relationship of the authentic catalysts. It is necessary, although challenging, to clarify its effect and provide practical strategies to tune the concentration and distribution of HO to optimize its influence. In this review, we focus on how HO in CO hydrogenation induces the structural evolution of catalysts and assists in the catalytic processes, as well as efforts to understand the underlying mechanism. We summarize and discuss some representative tuning strategies for realizing the rapid removal or local enrichment of HO around the catalysts, along with brief techno-economic analysis and life cycle assessment. These fundamental understandings and strategies are further extended to the reactions of CO and CO reduction under an external field (light, electricity, and plasma). We also present suggestions and prospects for deciphering and controlling the effect of HO in practical applications.