Hydroxide exchange membrane fuel cells offer possibility of adopting platinum-group-metal-free catalysts to negotiate sluggish oxygen reduction reaction. Unfortunately, the ultrafast hydrogen oxidation reaction (HOR) on platinum decreases at least two orders of magnitude by switching the electrolytes from acid to base, causing high platinum-group-metal loadings. Here we show that a nickel-molybdenum nanoalloy with tetragonal MoNi₄ phase can catalyze the HOR efficiently in alkaline electrolytes. The catalyst exhibits a high apparent exchange current density of 3.41 milliamperes per square centimeter and operates very stable, which is 1.4 times higher than that of state-of-the-art Pt/C catalyst. With this catalyst, we further demonstrate the capability to tolerate carbon monoxide poisoning. Marked HOR activity was also observed on similarly designed WNi₄ catalyst. We attribute this remarkable HOR reactivity to an alloy effect that enables optimum adsorption of hydrogen on nickel and hydroxyl on molybdenum (tungsten), which synergistically promotes the Volmer reaction.

氢氧化物交换膜燃料电池提供了采用无铂族金属催化剂来协商缓慢的氧还原反应的可能性。不幸的是，铂上的超快氢氧化反应 (HOR) 通过将电解质从酸转换为碱而降低了至少两个数量级，从而导致高铂族金属负载。在这里，我们展示了具有四方 MoNi ₄的镍钼纳米合金相可以在碱性电解质中有效地催化 HOR。该催化剂表现出每平方厘米 3.41 毫安的高表观交换电流密度，并且运行非常稳定，是最先进的 Pt/C 催化剂的 1.4 倍。使用这种催化剂，我们进一步证明了耐受一氧化碳中毒的能力。在类似设计的 WNi ₄催化剂上也观察到显着的 HOR 活性。我们将这种显着的 HOR 反应性归因于合金效应，该效应能够使镍上的氢和钼（钨）上的羟基实现最佳吸附，从而协同促进 Volmer 反应。