Novel Two-Dimensional Metal-Based π-d Conjugated Nanosheets as Photocatalyst for Nitrogen Reduction Reaction: The First-Principle Investigation.

Photocatalytic nitrogen reduction reaction (NRR) is becoming a promising route for producing green and sustainable ammonia under ambient conditions. However, the development of highly efficient photocatalysts for NRR still remains a grand challenge as a result of the sluggish activation of inert N 2 , the competitive hydrogen evolution reaction (HER), and inadequate photogenerated external potential, which usually cause extremely poor NRR performance and low light utilization efficiency. Herein, on the basis of density functional theory (DFT) computations, we rationally designed a series of two-dimensional (2D) π-d conjugated metal-B 3 N 3 (M 3 B 6 N 6 S 12 ) semiconductors. Using the electron "σ acceptance-π* backdonation" process, Mo 3 B 6 N 6 S 12 and Nb 3 B 6 N 6 S 12 can efficiently activate and reduce N 2 to ammonia with a rather low overpotential of 0.07 and 0.21 V, respectively. Importantly, a high photogenerated external potential enables spontaneous NRR on Mo 3 B 6 N 6 S 12 and Nb 3 B 6 N 6 S 12 under visible/infrared light irradiation, contributing to the extraordinary photoactivity of Mo 3 B 6 N 6 S 12 and Nb 3 B 6 N 6 S 12 as promising solar light-driven N 2 fixation catalysts. Meanwhile, the competing HER is effectively restrained. For the first time, we rationally propose a series of M 3 B 6 N 6 S 12 semiconductors as promising metal-based photocatalysts for N 2 reduction with extraordinary photoactivity and a high photogenerated external potential. This work paves a new path for the rational designing of 2D metal-based NRR photocatalysts with high activity, good selectivity, and high stability.