Nickel Single Atoms Anchored on Pyridinic N Dominated Porous Carbon for Enhanced Electrochemical 4-Electron Oxygen Reduction

Abstract

The four-electron oxygen reduction reaction (ORR) is at the heart of key renewable energy technologies including fuel cells and rechargeable metal-air batteries, but its wide use necessitates the development of efficient yet inexpensive catalysts. In this study, we have engineered single Ni atoms supported on nitrogen-doped porous carbon with a high content of pyridinic nitrogen (referred to as Ni₁–NC–G–NH₃). This was accomplished by pyrolyzing a Zn–Ni-ZIF–glucose composite and subsequently treating it with ammonia. Remarkably, the glucose facilitates the formation of isolated Ni atoms within an ammonia reduction atmosphere. Furthermore, we have attained a substantial nitrogen doping level of up to 13 atomic percent, with a significant enrichment of pyridinic nitrogen, constituting 39.5% of the total nitrogen content. Owing to the synergistic interaction between the pyridinic nitrogen and the Ni–N_x sites within the ZIF-derived porous carbon matrix, the Ni₁–NC–G–NH₃ catalyst demonstrates exceptional ORR catalytic activity and a nearly four-electron selectivity that rivals the commercial Pt/C catalyst in alkaline environments.