Synergy effect of the Niδ+-Nδ− atom pair for photocatalytic conversion of CO to ethanol: A computation study

By constructing a unique Niδ+–Nδ− atom pair, we designed a promising catalyst for the photocatalytic reduction of CO (pCOR), namely, anchoring a single Ni atom on a defective hexagonal boron nitride monolayer with a B-N divacancy (Ni/d-BN). The density functional theory (DFT) computations revealed that the synergy effect between the anchored Ni atom and its adjacent N atoms can capture multiple CO molecules, followed by their effective C–C coupling with a low kinetic barrier. Interestingly, these coupled CO species can be favorably reduced to ethanol (C2H5OH) product with a less negative limiting potential (–0.27 V), as compared with methane (CH4, –0.63 V), propanol (C3H7OH, –0.46 V), and the competitive hydrogen evolution reaction (HER, –0.84 V), suggesting the superior catalytic activity and the excellent selectivity of Ni/d-BN catalyst towards pCOR. Specially, this Ni/d-BN catalyst can significantly improve the visible light absorption with a suitable band position, enabling it ideal for solar-driven conversion of CO into C2H5OH. In particular, Ni/d-BN holds great potential for experimental synthesis due to its extremely high stability. Our findings not only open a new avenue to solve the problems of the high energy-consumption in FTS, but also offer a tandem strategy for CO2 conversion to multi-carbon products.