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Antimony compounds; Catalyst activity; Electrocatalysts; Morphology; Platinum compounds; Reaction kinetics; Alkalines; Amorphous antimony oxide; Bi-functional; Bifunctional mechanisms; Fast kinetics; Hydrogen evolution reactions; Hydrogen oxidation reaction; Ir nanowire; Long term stability; Ultra-thin; Nanowires
Abstract:
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.[Figure not available: see fulltext.] © 2023, Tsinghua University Press.
