Trio strategy of harmonizing electronic structure, interface, and microenvironment on amorphous indium oxide nanofiber for selective electrochemical ammonia synthesis

Abstract

Suppressing parasitic hydrogen evolution reaction (HER) remains a dilemma in developing aqueous electrochemical nitrogen reduction reaction (NRR). Nevertheless, previous studies have revealed the significant challenge of relying solely on electrocatalyst design to pursue selective NRR. Herein, we present a ‘Trio’ strategy to harmonize electronic structures of electrocatalysts, properties of interfaces, and configurations of microenvironments, thereby governing the intricate proton behaviors throughout the reaction, to suppress HER while boosting NRR. As proof-of-concept demonstration, the first designed amorphous InO-based nanofiber electrocatalyst, with optimized electronic state by oxygen vacancy and anchoring Mo species, is in conjunction with low-surface-energy monolayer interface and molecular-crowding microenvironment. Such rational synergy creates an advantageous catalytic configuration with decelerated proton diffusion and restricted proton transfer to active sites, thus achieving NH yield of 59.72 μg h mg and a FE of 30.60 %. We expect these findings will inspire “collaborative combat” strategies and desirable systems of NRR in the future.