Accelerated Photoreduction of CO₂ to CO over a Stable Heterostructure with a Seamless Interface

Abstract

Photocatalytic CO₂ reduction is a means of alleviating energy crisis and environmental deterioration. In this work, a rising two-dimensional (2D) material rarely reported in the field of photocatalytic CO₂ reduction, black phosphorus (BP) nanosheets, is synthesized, on which Co₂P is in situ grown by solvothermal treatment using BP itself as a P source. Co₂P on the BP nanosheets (BPs) surface can prevent the destruction of BPs in ambient air and, in the meantime, favor charge separation and CO₂ adsorption and activation during the catalytic process. Upon light irradiation, Co₂P can extract the photogenerated electrons effectively across the intimate interface and lower the CO₂ activation energy barrier, supported by both experimental characterizations and theoretical calculations. Benefitting from integrated advantages of BPs and Co₂P, the optimal Co₂P/BPs exhibit photocatalytic reduction of CO₂ to CO at a rate of 25.5 μmol g^-1 h^-1 with a selectivity of 91.4%, both of which are higher than those of pristine BPs. This work presents ideas for stabilizing BPs and improving their CO₂ reduction performance simultaneously.