Antimony oxides-protected ultrathin Ir-Sb nanowires as bifunctional hydrogen electrocatalysts
Bingyan Xu, Xuan Huang, Shangheng Liu, Zhiwei Hu, Cheng‐Wei Kao, Ting‐Shan Chan, Hongbo Geng, Ying Zhang, Xiaoqing Huang, Xiaoqing Huang, Xiaoqing Huang
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 (SbO x ) 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 SbO x 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/SbO x 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 H 2 O-occupied Sb sites can exert the intrinsic high activity of Ir and effectively optimize the absorption of OH⋆ both in alkaline HER/HOR electrolysis.