The quest to identify precious metal free hydrogen evolution reaction catalysts has received unprecedented attention in the past decade. In this Review, we focus our attention to recent developments in precious metal free hydrogen evolution reactions in acidic and alkaline electrolyte owing to their relevance to commercial and near-commercial low-temperature electrolyzers. We provide a detailed review and critical analysis of catalyst activity and stability performance measurements and metrics commonly deployed in the literature, as well as review best practices for experimental measurements (both in half-cell three-electrode configurations and in two-electrode device testing). In particular, we discuss the transition from laboratory-scale hydrogen evolution reaction (HER) catalyst measurements to those in single cells, which is a critical aspect crucial for scaling up from laboratory to industrial settings but often overlooked. Furthermore, we review the numerous catalyst design strategies deployed across the precious metal free HER literature. Subsequently, we showcase some of the most commonly investigated families of precious metal free HER catalysts; molybdenum disulfide-based, transition metal phosphides, and transition metal carbides for acidic electrolyte; nickel molybdenum and transition metal phosphides for alkaline. This includes a comprehensive analysis comparing the HER activity between several families of materials highlighting the recent stagnation with regards to enhancing the intrinsic activity of precious metal free hydrogen evolution reaction catalysts. Finally, we summarize future directions and provide recommendations for the field in this area of electrocatalysis.

中文翻译：

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无贵金属析氢催化剂设计与应用

在过去的十年中，对不含贵金属的析氢反应催化剂的探索受到了前所未有的关注。在这篇综述中，我们重点关注酸性和碱性电解质中无贵金属析氢反应的最新进展，因为它们与商业和接近商业的低温电解槽相关。我们对文献中常见的催化剂活性和稳定性能测量和指标进行了详细的回顾和批判性分析，并回顾了实验测量的最佳实践（在半电池三电极配置和两电极设备测试中） 。我们特别讨论了从实验室规模的析氢反应（HER）催化剂测量到单细胞测量的转变，这是从实验室扩大到工业环境的一个关键方面，但经常被忽视。此外，我们回顾了无贵金属 HER 文献中部署的众多催化剂设计策略。随后，我们展示了一些最常研究的无贵金属 HER 催化剂系列；酸性电解液用二硫化钼系、过渡金属磷化物、过渡金属碳化物；镍钼和过渡金属磷化物呈碱性。这包括对几种材料之间的 HER 活性进行比较的综合分析，突显出最近在增强无贵金属析氢反应催化剂的固有活性方面的停滞。最后，我们总结了电催化领域的未来方向并提供了建议。