Improving the slow kinetics of alkaline hydrogen electrode reactions, involving hydrogen oxidation and evolution reactions (HOR/HER) is highly desirable for accelerating the commercialization of alkaline exchange membrane-based fuel cells (AEMFCs) and water electrolyzers (AEMWEs). However, fundamental understanding of the mechanism for HOR/HER catalysis under alkaline media is still debatable. Here we develop an amorphous tungsten oxide clusters modified iridium-tungsten nanocrystallines (IrWO_x) which exhibited by far the highest exchange current density and mass activity, about three times higher than the commercial Pt/C toward alkaline HOR/HER. Density functional theory (DFT) calculations reveal the WO_x clusters act as a pivotal role to boost reversible hydrogen electrode reactions in alkaline condition but via different mechanisms, which are, hydrogen binding energy (HBE) mechanism for HOR and bi-functional mechanism for HER. This work is expected to promote our fundamental understanding about the alkaline HOR/HER catalysis and provide a new avenue for rational design of highly efficient electrocatalysts toward HOR/HER under alkaline electrolytes.

改善碱性氢电极反应的缓慢动力学，包括氢氧化和析出反应 (HOR/HER) 对于加速基于碱性交换膜的燃料电池 (AEMFC) 和水电解槽 (AEMWE) 的商业化是非常可取的。然而，对碱性介质下 HOR/HER 催化机制的基本理解仍然存在争议。在这里，我们开发了一种无定形氧化钨团簇改性的铱-钨纳米晶体 (IrWO _x )，它表现出迄今为止最高的交换电流密度和质量活性，比商业 Pt/C 高约三倍，用于碱性 HOR/HER。密度泛函理论 (DFT) 计算揭示了 WO _x簇在碱性条件下对促进可逆氢电极反应起着关键作用，但通过不同的机制，即 HOR 的氢结合能 (HBE) 机制和 HER 的双功能机制。这项工作有望促进我们对碱性 HOR/HER 催化的基本理解，并为在碱性电解质下合理设计 HOR/HER 高效电催化剂提供新途径。