Bismuth Ferrite as an Electrocatalyst for the Electrochemical Nitrate Reduction

Abstract

Electrochemical nitrate reduction has become an appealing "waste-to-wealth" approach for sustainable NH₃ synthesis owing to its mild operating conditions. However, developing catalysts with high activities and Faradaic efficiencies for this complicated eight-electron reaction is a great challenge. Herein, bismuth ferrite (BiFeO₃) flakes, with a distorted perovskite-type structure, are demonstrated to be excellent catalysts for electrochemical NH₃ synthesis via nitrate reduction, with a maximum Faradaic efficiency of 96.85%, NH₃ yield of 90.45 mg h^-1 mg_cat^-1, at -0.6 V <i>vs.</i> reversible hydrogen electrode. During the nitrate reduction reaction, the crystalline BiFeO₃ rapidly converts into an amorphous phase, which is stable in the long term reaction. These results open a new window for rational design of more active and durable electrocatalysts.