Highly efficient and durable H2-etched Ni@C for alkaline polymer electrolyte fuel cells application.

Completely precious metal-free alkaline polymer electrolyte fuel cells (APEFCs) are hindered by the lack of active non-precious metal hydrogen oxidation reaction (HOR) catalysts. Up to now, few studies have focused on the APEFC performance of non-precious metal HOR catalysts. Herein, upon simply adjusting the H 2 /Ar ratio during calcination, we synthesized a Ni-core carbon-shell (Ni@C) catalyst that exhibits an electrochemical surface area (ECSA)-normalized exchange current density of 0.090 mA cm−2, the highest among reported Ni-based HOR catalysts. More importantly, APEFC with the optimized catalyst, Ni-1% H 2 /Ar as anode catalyst, has achieved a peak power density of 670 mW cm−2 (H 2 –O 2) and 546 mW cm−2 (H 2 -Air CO 2 -free), higher than the state-of-the-art APEFC with Ni-based HOR catalysts, and can to stably work for 100 h at 200 mA cm−2. Characterization results show that H 2 is able to affect the particle size and etch the carbon shell of the catalysts during synthesis, which can boost the apparent HOR catalytic activity. Further experiments reveal that proper H 2 concentration during synthesis can lower the hydrogen binding energy (HBE), resulting in the enhanced intrinsic HOR catalytic activity of Ni-1% H 2 /Ar. • Ni@C catalyst exhibits a high intrinsic HOR catalytic activity of 0.090 mA cm−2. • The high HOR catalytic activity is derived from a H 2 -etched effect on carbon shell. • In APEFC test, Ni-1% H 2 /Ar reaches a PPD of 670 mW cm−2 (H 2 –O 2). • The APEFC is durable of 100 h at 200 mA cm−2. [ABSTRACT FROM AUTHOR]