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.

Plasma-induced defect engineering: Boosted the reverse water gas shift reaction performance with electron trap.

The reverse water gas shift reaction is a promising approach to solve the problem of excessive CO2 emission and energy shortage. However, insufficient charge separation efficiency of numerous semiconductor photocatalysts hamper their CO2 photoreduction performance. Defect engineering is considered as a desired method to tackle that shortcoming by the boosting the electron capture process. Herein, the sulfur vacancies-rich CdIn2S4 (VS-CdIn2S4) was synthesized by an efficient low-temperature plasma-enhanced technology. The outstanding VS-CdIn2S4 shows a more excellent CO formation rate of 103.6 µmol g-1 h-1 comparing that of traditional CdIn2S4 (31.36 µmol g-1 h-1). The density function theory (DFT) calculation reveals the sulfur vacancy is the center of electron capture. Moreover, the formed defect level after introduce of surface vacancy effectively optimizes the light absorption propertie of the prepared material. Thus, the enhanced photocatalytic CO2 reduction performance can be attributed to the double improvement of light absorption and carrier separation. This work provides a novel and facile strategy to mediate carriers' movement behavior via defect engineering for high-efficient CO2 photoreduction.