College of Energy, Soochow University, Suzhou 215006, China.
Suzhou Institute of Nanotech and Nanobionics, Chinese Academy of Sciences, Suzhou 215123, China.
Proc Natl Acad Sci U S A. 2023 Jan 3;120(1):e2209760120. doi: 10.1073/pnas.2209760120. Epub 2022 Dec 27.
Using hydrogen as a fuel is an effective way to combat energy crisis and at the same time reduce greenhouse gas emission. Alkaline hydrogen evolution reaction (HER) is one important way to obtain green hydrogen, which however is energy intensive and is difficult to obtain high efficiencies even when using state-of-the-art noble metal catalysts. Here, we report a three-component catalytic system using only non-noble elements, consisting of cobalt oxide clusters and single molybdenum atoms supported on oxyanion-terminated two-dimensional MXene, which enabled the unusual generation of hydrogen by a kinetically fast Volmer-Tafel process in an alkaline electrolyte. The key feature of this catalyst is that the three components are connected by bridging oxygen, which serves to immediately adsorb H* produced during water dissociation on cobalt oxide and relay it to the molybdenum single-atom catalyst. On the Mo atom, due to this unique coordination environment, the relayed H* intermediates directly combine and desorb, realizing H generation through an unusual Tafel pathway. The presence of bridging oxygen increases the acidity of the catalyst as Brønsted acid with the reversible adsorption and donation of a proton, thus eliminating the need for acid addition and ensuring excellent and sustainable alkaline HER performance. The performance of our catalyst is comparable to that of the commercial noble metal catalyst PtRu/C. Our work makes a significant contribution to designing efficient non-noble catalysts for alkaline HER electrocatalysis.
使用氢气作为燃料是应对能源危机和同时减少温室气体排放的有效方法。碱性析氢反应（HER）是获取绿色氢气的重要途径之一，但该过程能量密集，即使使用最先进的贵金属催化剂，也难以获得高效率。在这里，我们报告了一种仅使用非贵金属元素的三组分催化体系，由负载在氧阴离子终止二维 MXene 上的氧化钴团簇和单钼原子组成，该体系在碱性电解质中通过动力学快速的 Volmer-Tafel 过程实现了氢的异常生成。该催化剂的关键特征是三个组分通过桥氧连接，这有助于立即吸附在钴氧化物上在水离解过程中产生的 H*，并将其传递到钼单原子催化剂上。在 Mo 原子上，由于这种独特的配位环境，传递的 H*中间体直接结合并脱附，通过不寻常的塔菲尔途径实现 H 的生成。桥氧的存在增加了催化剂的酸度，作为布朗斯台德酸可逆地吸附和提供质子，从而无需添加酸，并确保优异和可持续的碱性 HER 性能。我们催化剂的性能可与商业贵金属催化剂 PtRu/C 相媲美。我们的工作为设计用于碱性 HER 电催化的高效非贵金属催化剂做出了重要贡献。
