德国慕尼黑大学Emiliano Cortes团队报道了利用RuCo合金纳米片优化Ru位点的氢键结合，实现高效的碱性析氢。相关研究成果于2021年11月25日发表于国际顶尖学术期刊《德国应用化学》。

钌基催化剂以其优异的性能和理想的成本，成为碱性析氢反应（HER）中取代铂（Pt）的热门催化剂。Ru位点的氢键（Ru-H）是限制HER活性的重要因素。

该文中，密度泛函理论（DFT）模拟表明Ru-H结合能的本质是Ru的4dz 2轨道和H的1s轨道之间的强相互作用。Ru位和衬底（Co和Ni）之间的电荷转移导致Ru的4dz 2-带中心适当向下移动，导致RuCo系统中H*的吉布斯自由能为0.022eV，与纯Ru系统中的0.133eV相比大幅降低。该理论预测已通过RuCo合金纳米片（RuCo ANSs）得到实验证实。RuCo合金纳米片通过快速共沉淀法和温和的电化学还原法制备。

结构表征表明，Ru原子以平面对称和Z方向不对称配位结构作为孤立的活性中心嵌入到Co衬底中，获得了最佳的4dz2调制电子结构。氢传感器和程序升温脱附（TPD）测试表明，RuCo-ANSs中的Ru-H相互作用比纯Ru纳米颗粒增强。因此，RuCo ANSs在10 mA/cm²时达到10 mV的超低过电位，在1 M KOH中达到20.6 mV/dec的塔菲尔斜率，优于商用Pt/C。

该研究为通过优化活性位点的金属-H结合能促进碱性HER提供了新的思路。

附：英文原文

Title: Optimizing hydrogen binding on Ru sites with RuCo alloy nanosheets for efficient alkaline hydrogen evolution

Author: Chao Cai, Kang Liu, Yuanmin Zhu, Pengcheng Li, Qiyou Wang, Bao Liu, Shanyong Chen, Huangjingwei Li, Li Zhu, Hongmei Li, Junwei Fu, Yu Chen, Evangelina Pensa, Junhua Hu, Ying-Rui Lu, Ting-Shan Chan, Emiliano Cortes, Min Liu

Issue&Volume: 2021-11-25

Abstract: Ruthenium (Ru)-based catalysts, with considerable performance and desirable cost, become highly concerned candidates to replace platinum (Pt) in alkaline hydrogen evolution reaction (HER). The hydrogen binding at Ru sites (Ru-H) is an important factor limiting the HER activity. Herein, density functional theory (DFT) simulations show that the essence of Ru-H binding energy is the strong interaction between the 4dz  2  orbital of Ru and 1s orbital of H. The charge transfer between Ru sites and substrates (Co and Ni) causes the appropriate downward shift of the 4dz  2  -band center of Ru, which results in a Gibbs free energy of 0.022 eV for H* in RuCo system, much decrease compared to 0.133 eV in pure Ru system. This theoretical prediction has been experimentally confirmed using RuCo alloy nanosheets (RuCo ANSs). They were prepared via fast co-precipitation method followed with a mild electrochemical reduction. Structure characterizations reveal that the Ru atoms are embed into Co substrate as isolated active sites with the planar symmetric and Z-direction asymmetric coordination structure, obtaining an optimal 4dz  2  modulated electronic structure. Hydrogen sensor and temperature program desorption (TPD) tests demonstrate the enhanced Ru-H interactions in RuCo ANSs than pure Ru nanoparticles. As a result, the RuCo ANSs reach an ultra-low overpotential of 10 mV at 10 mA/cm  2  and a Tafel slope of 20.6 mV/dec in 1 M KOH, outperforming that of the commercial Pt/C. This holistic work provides a new insight to promote alkaline HER by optimizing metal-H binding energy of active sites.

DOI: 10.1002/anie.202113664

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202113664