B-site cation synergy in Mn doped LaCoO3 for enhanced electrocatalysts for electrochemical reduction of nitrate

Abstract

Electroreduction of nitrate is a promising strategy that has gained more attention in current years. Perovskites are promising catalysts for electroreduction of nitrate due to its special ABO3 structure, which makes it possible to regulate its physical and chemical properties to achieve better nitrate removal efficiency. In this study, we doped Mn cation into the B-site of LaCoO3 and evaluated its performance for electroreduction of nitrate. After appropriate portion of Mn was doped in LaCoO3, optimized Co2+/Co3+ ratio as well as larger surface area and pore structures were acquired. The optimized doped materials LaMn0.6Co0.4O3, which achieved 41.92 % higher nitrate removal efficiency than that of LaCoO3, was in good function under different operating conditions of initial NO3– concentration, cathode potential and pH value and remained outstanding stability after ten consecutive cycles of reaction. Depending on the valence change of Co and Mn of cathode before and after electrocatalysis, we deduced that doped Mn cation not only affected the valence of Co cation but also activated adsorbed oxygen to offer electron and accelerated electron transfer. Generally, this study provided a novel thread to reveal synergism of doped metal cations of perovskites in electroreduction of nitrate.