Engineering cobalt-pyridinic N moieties on hybrid interfaces for alkaline hydrogen evolution

Abstract

Efficient establishment of transition-metal electrocatalysts is critical for the advancement of clean energy. Herein, we utilize laser ablation to controllably fabricate plenty of cobalt (Co)-pyridinic nitrogen (N) moieties on the hybrid interface between CoO and N-modified graphene with mesoporous-rich architectures. This approach results in a tri-functional catalyst with excellent performance in three crucial electrocatalytic reactions, i.e., hydrogen and oxygen evolution (HER and OER), and oxygen reduction (ORR). More importantly, subsequent control experiments highlight the essential role of Co-pyridinic N bonds in boosting HER. As we previously reported, the catalyst exhibited exceptional performance for oxygen-related catalysis (ORR/OER) in 1.0 M KOH. In this study, it only requires a low exterior voltage of 1.64 V to fulfill the current density of 10 mA cm−2 for driving overall water splitting in the same electrolyte. The Co-pyridinic N moieties present in the catalyst are credited for the superior performance, as they can facilitate the protons adsorption with a decreased Gibbs free energy, and also serve as reaction centers for promoting water dissociation. This study will pave a new avenue for the installation of highly sought-after electrochemical energy technologies.