Theoretical Study On Photo-electrocatalytic Performance Of Low-dimensional Nanomaterials

Ammonia?NH₃?is not only an important chemical feedstocks in various fields,but also a promising carbon-free energy storage intermediate.Therefore,fixing naturally abundant nitrogen?N₂?into NH₃ is an extremely necessary conversion.Currently,electrocatalytic reduction of N₂ under ambient conditions is a promising way for green and sustainable production of NH₃,but the design and development of new electrocatalysts with high-efficiency and high-selectivity remains a great challenge.In addition,energy shortages and global warming have seriously threatened the future development of modern society.Therefore,the conversion of CO₂ into other high value-added carbon-based feedstocks and fuels has been regarded as the most thorough and fundamental solution.However,the most common product produced with high efficiency and selectivity?i.e.,Faradaic efficiency?through CO₂ reduction at low energy cost is carbon monoxide?CO?,which possesses relatively low value and energy density.Therefore,the further photocatalytic reduction of CO into other valuable multi-carbon chemicals is significant for desirable carbon cycling,as well as high efficiency conversion and high density storage of solar energy.In this paper,by means of density functional theory?DFT?computations,we evaluated the electrocatalytic performance of a series of singe metal atoms catalysts and cubic boron phosphide?BP?and boron arsenide?BAs?towards nitrogen reduction reaction?NRR?.Single boron?B?atom decorated on the optically active C₂N monolayer as an efficient and stable photocatalyst for visible light driven CO reduction?CORR?.The results are as follows:?1?Single Ti,Co,Mo,W,and Pt atoms supported on g-C₃N₄ monolayer show good catalytic activity for NRR.In particular,the single tungsten?W?atom anchored on g-C₃N₄?W@g-C₃N₄?exhibits the highest catalytic activity toward NRR with a limiting potential of-0.35 V via associative enzymatic pathway,and can well suppress the competing hydrogen evolution reaction.?2?Gas phase N₂ can be sufficiently activated on the B-terminated?111?polar surface of BP and BAs,and effectively reduced to NH₃ via an enzymatic pathway with an extremely low limiting potential?-0.12 V on BP and-0.31 V on BAs,respectively?.Especially,the two proposed B-terminated?111?surfaces not only have a large active region for N₂ reduction,but also can significantly inhibit the competitive hydrogen evolution reaction,thus have rather high efficiency and selectivity for NRR.?3?On the designed B/C₂N catalyst,CO can be efficiently reduced into ethylene?C₂H₄?and propylene?C₃H₆?with free energy increase of 0.22 eV for the potential-determining step,which greatly benefits from the pull-push function of the B-N FLPs composed of the decorating B and the host N atoms.Moreover,the newly designed B/C₂N catalyst shows significant visible light absorption with suitable band positions for CO reduction into C₂H₄ and C₃H₆.