Electrocatalytic Nitrogen Reduction Performance of Si-doped 2D Nanosheets of Boron Nitride Evaluated via Density Functional Theory

摘要

Electrochemical nitrogen fixation under ambient conditions is proposed as a sustainable alternative to the traditional Haber-Bosch method to combat both a global energy crisis and climate change. However, effective catalysts for electrocatalytic nitrogen reduction reaction (eNRR) under ambient conditions, a crucial part for the electrocatalysis system, still face large challenges of low Faradic efficiency (FE) and low yield of ammonia. Here, we propose Si-doped BN 2D nanosheets (BNNS) as a new class of metal-free catalysts, and computationally study their performance in eNRR by density functional theory (DFT). The calculations show that the Si atom in the boron-edge site exhibits the highest activity with the over-potential (eta) of 1.06 V from the first hydrogenation step, which is close in value to the benchmark of this reaction, the flat Ru(0001) surface (eta=0.92 V). Moreover, Si-doping can greatly enhance the conductivity of pristine BNNS, making it a good candidate for electrocatalysis. Overall, this research opens up a new direction of designing high-performance Si-based 2D catalysts for dinitrogen fixation beyond the hotspot research of boron- or transition metal-based catalysts.