Boosting borohydride oxidation kinetics by manipulating hydrogen evolution and oxidation through octahedral Pt–Ni/C for high-performance direct borohydride fuel cells

Abstract

Direct borohydride fuel cells (DBFCs) outperform the other direct liquid fuel cells by a higher open circuit voltage and energy density. However, their benign performance and efficiency are highly dependent on high-performance anode catalysts. This study delves into the enhancement of borohydride oxidation reaction (BOR) kinetics through an octahedral Pt–Ni/C catalyst. The Pt(111) facets of the catalyst exhibit a combination of abundant active sites exposed for BOR and the inherent ability to suppress hydrolysis reaction. Furthermore, the synergistic incorporation of Ni modifies the electronic structure of Pt, resulting in enhanced OH− adsorption and hydrogen oxidation reaction (HOR) activity. This multifaceted approach not only mitigates hydrogen accumulation but also boosts the overall BOR efficiency. The elaborate electrochemical measurements along with comprehensive characterizations elucidate the superior catalytic activity and stability of Pt–Ni/C over commercial Pt/C catalysts. Specifically, DBFCs employing the Pt–Ni/C catalyst manifest considerably higher open circuit voltage (1.05 V), peak power density (1.82 W cm−2) and fuel efficiency (63.96 %) than those of DBFCs employing Pt/C catalyst. Through these efforts, we provide significant insight into the design of high-performance anode catalyst for DBFCs.