Interface- and Surface-Engineered PdO-RuO2 Hetero-Nanostructures with High Activity for Hydrogen Evolution/Oxidation Reactions

Active catalysts for HER/HOR are crucial to develop hydrogen-based renewable technologies. The interface of hetero-nanostructures can integrate different components into a single synergistic hybrid with high activity. Here, the synthesis of PdO-RuO2-C with abundant interfaces/defects was achieved for the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR). It exhibited a current density of 10 mA cm(-2) at 44 mV with a Tafel slope of 34 mV dec(-1) in 1 m KOH. The HER mass activity was 3 times higher in base and comparable to Pt/C in acid. The stability test confirmed high HER stability. The catalyst also exhibited excellent HOR activity in both media; in alkaline HOR it outperformed Pt/C. The exchange current density i(0,m) of PdO-RuO2/C was 522 mA mg(-1) in base, which is 58 and 3.4 times higher than those of Pd/C and Pt/C. The HOR activity of PdO-RuO2/C was 22 and 300 times higher than those of PdO/C in acid and base. Improvement of HER/HOR kinetics in different alkaline electrolytes was observed in the order K+

Automated summary

The synthesis of PdO-RuO2-C resulted in a catalyst with abundant interfaces/defects, showing high HER and HOR activity in alkaline conditions. It exhibited excellent stability and outperformed Pt/C in alkaline HOR activity. Improvement of HER/HOR kinetics was observed in different alkaline electrolytes.