Efficient FeCoNiCuPd thin-film electrocatalyst for alkaline oxygen and hydrogen evolution reactions

The creation of high-performing, robust bifunctional electrocatalysts for both cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) in water-splitting is crucial for producing emerging hydrogen economy. Here we report a high entropy alloy (HEA) - FeCoNiCuPd - thin film catalyst, which demonstrated excellent alkaline HER and OER performance with ultralow overpotentials as low as 29 mV for HER and 194 mV for OER at a current density of 10 mA cm(-2). The outstanding catalytic activity for HER was found to originate from the multiple active sites present on the FeCoNiCuPd surface, while for OER it came from the highly functional (FeCoNi)-oxyhydroxide species formed on the film surface. Moreover, the two-electrode electrolyzer made of the FeCoNiCuPd film electrodes required a low cell voltage of 1.52 V to achieve 10 mA cm(-2) in 1.0 M KOH, greatly outperforming commercially available Pt/C parallel to RuO2 electrodes, while maintaining a notable durability. This work demonstrated the remarkable potential of a HEA thin film in catalyzing watersplitting process.

Automated summary

In this study, a high entropy alloy (HEA) - FeCoNiCuPd - thin film catalyst was reported to exhibit excellent catalytic performance for both alkaline HER and OER. The remarkable HER activity originated from the multiple active sites on the FeCoNiCuPd surface, while the OER activity was attributed to the formation of highly functional (FeCoNi)-oxyhydroxide species on the film surface. The HEA thin film catalyst showed the potential for efficient water-splitting process at low cell voltage and maintained good durability.