Lattice-strain and Lewis acid sites synergistically promoted nitrate electroreduction to ammonia over PdBP nanothorn arrays

Abstract

The electrocatalytic reduction of nitrate to ammonia is a promising approach to mitigating nitrate pollution and simultaneously yielding value-added chemicals, which however suffers from insufficient current efficiency and ammonia yield rate. In this work, we design and synthesize ternary PdBP nanothorn arrays by a facile B,P-co-doping strategy using Pd nanothorn arrays as structure and composition templates for efficient ammonia synthesis from nitrate. Characterization and electrochemical studies reveal that the doped B and P atoms can serve as Lewis acid sites to enhance the adsorption of nitrate ions, and the lattice strain induced by B and P co-doping can effectively regulate the electronic configuration and increase the active sites, which synergistically suppress the hydrogen evolution and boost the nitrate-to-ammonia capability. Notably, the PdBP nanothorn arrays could improve the ammonia selectivity by 25% and faradaic efficiency by 35%, compared with un-doped Pd nanothorn arrays.