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

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.