深圳大学何传新小组在最新研究中，通过在锰氧化物中构建不饱和Ru原子阵列促进中性水还原。相关论文发表在2024年9月23日出版的《德国应用化学》杂志上。

最近以来，碳纳米材料上的Ru单原子在酸性析氢反应(HER)中表现出超高的活性，但由于在中性电解质中水解离生成H*中间体和随后H*重组的动力学缓慢，这一类材料在中性环境下析氢反应活性仍然很低。

研究组在锰氧化物(如Li₄Mn₅O₁₂)中合成了有序的低配位Ru原子阵列，同时促进了水解离和H*重组，它们在中性介质中比商业Pt/C的析氢反应(HER)活性提高了6倍。

对照实验表明，低配位的Ru原子与水分子氧原子亲和力强，有利于水解离快速生成H*。

更重要的是，电化学和理论结果都表明，阵列结构允许两个水分子在两个相邻的Ru原子上激活，从而通过Tafel步骤实现H*-H *的直接重组，而孤立的Ru原子只能通过缓慢的Heyrovsky步骤，逐一激活水以实现H*的重组。

显然，这项工作为通过构建具有可控配位环境的有序金属原子组装体，来提高电催化活性开辟了新的途径。

附：英文原文

Title: Constructing Unsaturated Ru Atom Arrays Confined in Mn Oxides to Boost Neutral Water Reduction

Author: Qi Hu, Jianyong Cao, Shuai Qi, Na Meng, Jingwen Zhao, Tianchi Huang, Jiao You, Taiyu Liang, Chunyan Shang, Jiaying Yu, Hengpan Yang, Chuanxin He

Issue&Volume: 2024-09-23

Abstract: Recently, Ru single atoms supported on carbon nanomaterials have demonstrated ultrahigh activity for acid hydrogen evolution reaction (HER), however their neutral HER activity remains low due to the sluggish kinetics for both the water dissociation step to generate H* intermediates and subsequent H* recombination in neutral electrolytes. Here, we synthesize ordered low-coordinated Ru atom arrays confined in Mn oxides (i.e., Li4Mn5O12) for concurrently boosting the water dissociation and H* recombination, thus achieving a 6-fold HER activity enhancement than commercial Pt/C in neutral media. Control experiments indicate that low-coordinated Ru atoms with strong affinity to oxygen atoms of water molecules facilitate the water dissociation to rapidly generate H*. More importantly, both electrochemical and theoretic results uncover that the array-like structure allows the activation of two water molecules on two adjacent Ru atoms for enabling direct H*–H* recombination via the Tafel step, while isolated Ru atoms can only activate water one by one for recombining H* via the sluggish Heyrovsky step. Clearly, this work paves new avenues to boosting the electrocatalytic activity by constructing ordered metal atoms assembles with controllable coordination environments.

DOI: 10.1002/anie.202416402

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202416402