Electrocatalysis for CO conversion: from fundamentals to value-added products.

The continuously increasing CO released from human activities poses a great threat to human survival by fluctuating global climate and disturbing carbon balance among the four reservoirs of the biosphere, earth, air, and water. Converting CO to value-added feedstocks via electrocatalysis of the CO reduction reaction (CORR) has been regarded as one of the most attractive routes to re-balance the carbon cycle, thanks to its multiple advantages of mild operating conditions, easy handling, tunable products and the potential of synergy with the rapidly increasing renewable energy (i.e., solar, wind). Instead of focusing on a special topic of electrocatalysts for the CORR that have been extensively reviewed elsewhere, we herein present a rather comprehensive review of the recent research progress, in the view of associated value-added products upon selective electrocatalytic CO conversion. We initially provide an overview of the history and the fundamental science regarding the electrocatalytic CORR, with a special introduction to the design, preparation, and performance evaluation of electrocatalysts, the factors influencing the CORR, and the associated theoretical calculations. Emphasis will then be given to the emerging trends of selective electrocatalytic conversion of CO into a variety of value-added products. The structure-performance relationship and mechanism will also be discussed and investigated. The outlooks for CO electrocatalysis, including the challenges and opportunities in the development of new electrocatalysts, electrolyzers, the recently rising operando fundamental studies, and the feasibility of industrial applications are finally summarized.