Tuning of CO Reduction Selectivity on Metal Electrocatalysts.

Climate change, caused by heavy CO emissions, is driving new demands to alleviate the rising concentration of atmospheric CO levels. Enlightened by the photosynthesis of green plants, photo(electro)chemical catalysis of CO reduction, also known as artificial photosynthesis, is emerged as a promising candidate to address these demands and is widely investigated during the past decade. Among various artificial photosynthetic systems, solar-driven electrochemical CO reduction is widely recognized to possess high efficiencies and potentials for practical application. The efficient and selective electroreduction of CO is the key to the overall solar-to-chemical efficiency of artificial photosynthesis. Recent studies show that various metallic materials possess the capability to play as electrocatalysts for CO reduction. In order to achieve high selectivity for CO reduction products, various efforts are made including studies on electrolytes, crystal facets, oxide-derived catalysts, electronic and geometric structures, nanostructures, and mesoscale phenomena. In this Review, these methods for tuning the selectivity of CO electrochemical reduction of metallic catalysts are summarized. The challenges and perspectives in this field are also discussed.