Antimony oxides-protected ultrathin Ir-Sb nanowires as bifunctional hydrogen electrocatalysts

Developing electrocatalysts with fast kinetics and long-term stability for alkaline hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is of considerable importance for the industrial production of green and sustainable energy. Here, an ultrathin Ir-Sb nanowires (Ir-Sb NWs) protected by antimony oxides (SbOx) was synthesized as an efficient bifunctional catalyst for both HOR and HER under alkaline media. Except from the much higher mass activities of Ir-Sb nanowires than those of Ir nanowires (Ir NWs) and commercial Pt/C, the SbOx protective layer also contributes to the maintenance of morphology and anti-CO poisoning ability, leading to the long-term cycling performance in the presence of CO. Specifically, the Ir-Sb NW/SbOx exhibits the highest catalytic activities, which are about 3.5 and 4.8 times to those of Ir NW/C and commercial Pt/C toward HOR, respectively. This work provides that the ultrathin morphology and H2O-occupied Sb sites can exert the intrinsic high activity of Ir and effectively optimize the absorption of OH ⋆ both in alkaline HER/HOR electrolysis.

Automated summary

In this study, an ultrathin Ir-Sb nanowires protected by antimony oxides (SbOx) was synthesized as an efficient bifunctional catalyst for both alkaline hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER). The SbOx protective layer not only contributes to the maintenance of morphology and anti-CO poisoning ability but also enhances the catalytic activities of Ir-Sb nanowires in HOR and HER. The ultrathin morphology and H2O-occupied Sb sites optimize the absorption of OH⋆ in alkaline HER/HOR electrolysis, leading to superior catalytic performance.