Activating two-dimensional Ti3C2Tx-MXene with single-atom cobalt for efficient CO2 photoreduction

Artificial CO2 photoreduction to solar fuels represents an ecofriendly and sustainable solution to obtain "sunshine" feedstocks by using renewable energy media. Herein, we report that single cobalt atoms anchored on two-dimensional Ti3C2Tx-MXene nano-sheets act as an efficient photocatalytic ensemble for visible-light CO2 reduction, wherein the Ti3C2Tx nanosheets bridge visible-light absorbers (ruthenium complex) with cobalt active sites. The single cobalt atoms build strong interactions with Ti(3)C(2)T(x )by forming metal-oxygen/carbon bonds, resulting in the formation of the Co-Ti3C2Tx ensemble. As a result, the production rate of CO reaches a high value of 6.06 mmol h(-1) g(-1) over the optimal Co-Ti3C2Tx which markedly exceeds previous MXene-based catalysts for CO2 photoreduction. Theoretical calculation manifests that the isolated Co atoms coordinated with Ti3C2Tx can effectively facilitate the generation of CO. This work may provide a new line of thought into the rational design of high-activity MXene-based photocatalysts toward artificial CO2 conversion.