Boron Phosphide Nanoparticles: A Nonmetal Catalyst for High-Selectivity Electrochemical Reduction of CO₂ to CH₃ OH.

Abstract

Electrocatalysis has emerged as an attractive way for artificial CO₂ fixation to CH₃ OH, but the design and development of metal-free electrocatalyst for highly selective CH₃ OH formation still remains a key challenge. Here, it is demonstrated that boron phosphide nanoparticles perform highly efficiently as a nonmetal electrocatalyst toward electrochemical reduction of CO₂ to CH₃ OH with high selectivity. In 0.1 m KHCO₃ , this catalyst achieves a high Faradaic efficiency of 92.0% for CH₃ OH at -0.5 V versus reversible hydrogen electrode. Density functional theory calculations reveal that B and P synergistically promote the binding and activation of CO₂ , and the rate-determining step for the CO₂ reduction reaction is dominated by *CO + *OH to *CO + *H₂ O process with free energy change of 1.36 eV. In addition, CO and CH₂ O products are difficultly generated on BP (111) surface, which is responsible for the high activity and selectivity of the CO₂ -to-CH₃ OH conversion process.