Efficient Electroreduction of CO ₂ to CO via Complexation–Precipitation Synthesized Silver Phosphate Nanoparticles

ABSTRACT The electrochemical CO 2 reduction reaction (ECO 2 RR) has emerged as a promising strategy for transforming CO 2 into value‐added chemicals and fuels. However, the weak adsorption strength of *COO − significantly hindered CO formation on the active surface sites of Ag. Herein, the nanostructured silver phosphate (Ag 3 PO 4 ) catalyst revealed that PO 4 3− promoted the formation of key intermediates, *COO − and *COOH, with in situ Raman spectroscopy. The Ag 3 PO 4 catalyst was prepared via a complexation‐precipitation method, which showed excellent performance in the selective reduction of CO 2 to CO. Notably, Ag 3 PO 4 undergoes structural reconstruction during electrochemical operation, leading to the formation of Ag/Ag 3 PO 4 as the dominant active sites. This reconstruction enables consistently delivered Faradaic efficiencies for CO (FE CO ) exceeding 95% over a wide potential window from −0.477 V to −1.077 V versus RHE, with FE CO surpassing 98% between −0.477 and −0.877 V versus RHE. It was demonstrated that a partial CO current density of 146 mA cm −2 at ‐0.777 V versus RHE was achieved in the flow cell, approximately a 2.5‐fold increase over that achieved by pure silver. This work presents a phosphate‐based catalyst design, demonstrating potential for application in ECO 2 RR.