摘要：Electrochemical CO_(2)reduction reaction(CO_(2)RR)driven by sustainable energy has emerged as an attractive route to achieve the target of carbon *** is one of the most economically viable products,and electrocatalytic CO_(2)RR to formate is a promising ***-pressure H-cell electrolyzer is easy to operate and allows high CO_(2)solubility for realizing high current density,but the design of highly efficient catalysts for working under high CO_(2)pressures remains ***-based catalysts exhibit high formate selectivity,but suffer from limited ***,we report a high-performance catalyst,which is derived from BiPO_(4)nanopolyhedrons during electrocatalytic CO_(2)RR to formate in neutral solution under high CO_(2)pressures.A high partial current density of formate(534 mA cm^(−2))and formate formation rate(9.9 mmol h^(−1) cm^(−2))with a formate Faradaic efficiency of 90%have been achieved over BiPO_(4)-derived catalyst at an applied potential of−0.81 V *** under 3.0 MPa CO_(2)*** discover that BiPO_(4)nanopolyhedrons evolve into metallic Bi nanosheets with rich grain boundaries in electrocatalytic CO_(2)RR under high CO_(2)pressures,and the grain boundaries of the BiPO_(4)-derived catalyst play a vital role in promoting electrocatalytic CO_(2)RR to *** theoretical studies reveal that the charge redistribution occurs at the grain boundaries of Bi surface,and this promotes CO_(2)activation and increases HCOO^(*)intermediate stability,thus making the pathway for CO_(2)RR to formate more selective and *** work not only demonstrates a highly efficient catalyst for CO_(2)RR to formate but also discovers a unique feature of catalyst evolution under high CO_(2)pressures.