Dynamic piezoelectric response facilitating lead-free ceramic to efficiently electrosynthesize hydrogen peroxide via oxygen reduction

Abstract

Optimizing the interface property of the catalyst-electrolyte by the physical field modulation could improve the electrocatalytic performance, yet the associated investigations on the two-electron oxygen reduction reaction (2e− ORR) are still scarce. Herein, we develop a facile, green, and economic piezoelectricity-indued local electric field strategy based on the piezo-response of the polarized lead-free bismuth sodium titanate (P-BNT) ceramic under the dynamic operational conditions of ORR. The as-emerged electric field at the immediate vicinity of the ceramic catalyst surface greatly optimizes its adjacent OH- coverage from the alkaline electrolyte and lowers the local concentration of the HO2− product. Therefore, the adsorption ability of oxygen-containing intermediates during the ORR process is ameliorated, and the peroxide product disproportionation is simultaneously inhibited. Compared with the unpolarized ceramic catalyst, P-BNT prepared at a kilogram scale displayed excellent 2e- ORR selectivity over 90% in a wide potential window of 0.45 V in 0.1 M KOH with a summit of ∼100%, outmatching most state-of-the-art alkaline 2e− ORR catalysts. The current work could realize the improved electrosynthesis efficiency of hydrogen peroxide with practical application potentials, especially considering the environmentally-friendly, extensively-studied, and technically-mature lead-free piezoelectric BNT ceramic that can be facilely prepared in a low cost and large scale.