Engineering Co@Co3mo3n/Npcs Heterostructured Ultrathin Nanosheets Electrocatalysts with Favorable Electronic Configuration for Boosting Alkaline Overall Water Electrolysis

Abstract

The rational architecture of high-performance electrocatalyst is becoming imperative for H2 production from electrochemical water splitting. Herein, the pioneering fabrication of Co@Co3Mo3N heterojunctions immobilized onto N-doped porous carbon substrates (abbreviated as Co@Co3Mo3N/NPCs) are effectuated by a combination of wet-impregnation proceedings of Co,Mo/polyaniline (PANI) precursor and subsequent carbonization/nitridation treatment. This construction can furnish the multitudinous Co@Co3Mo3N heterojunction interfacial sites and simultaneously exert the extremely strong interaction between Co@Co3Mo3N nanosheets and NPCs substrates, which not only strengthens the structural stability and accelerates interfacial electron transfer, but also triggers the synergistic effect to encourage the rearrangement of the electronic configuration and the majorization of electrochemically active sites, thus contributing to the comprehensive improvement of the electrocatalytic HER and OER performance. On these grounds, the synthesized Co@Co3Mo3N/NPCs electrocatalyst can deliver the exceptional electrocatalytic HER and OER performance with ultra-low overpotentials of 37 mV and 203 mV at a current density of 10 mA cm-2. Meanwhile, when Co@Co3Mo3N/NPC simultaneously acts as the HER and OER electrodes in H-type alkaline electrolyzer, the extremely low voltage of 1.41 V is obtained for transferring the current density of 10 mA cm-2 with an excellent durability. In addition, the Co@Co3Mo3N/NPC electrocatalysts are assembled into zero-gap alkaline electrolyzer for overall water splitting, which afford an ultra-low voltage of 1.80 V at a current density of 500 mA cm-2 with ultra-long lifespan of 2400 h. Therefore, this work can provide fire-new perspective and inspiration for synthesizing the art-of-the-state bifunctional electrocatalysts for further commercial application.

Keywords: Water electrolysis, HER&OER, Co@Co3Mo3N/NPCs bifunctional electrocatalysts, Electronic configuration tailoring