在硫化钼基面上调控原子级协同活性中心用于碱氢演化反应  

Atomically tailoring synergistic active centers on molybdenum sulfide basal planes for alkaline hydrogen generation

作　　者：罗旭宇 王颖 杨光 刘璐 郭诗颖 崔义 许小勇[1] Xuyu Luo;Ying Wang;Guang Yang;Lu Liu;Shiying Guo;Yi Cui;Xiaoyong Xu(School of Physics Science&Technology,Yangzhou University,Yangzhou 225002,Jiangsu,China;i-Lab,Vacuum Interconnected Nanotech Workstation,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,Suzhou 215123,Jiangsu,China)

机构地区：[1]扬州大学物理科学与技术学院,江苏扬州225002 [2]中国科学院苏州纳米技术与纳米仿生研究所,真空互联纳米技术工作站,江苏苏州215123

出　　处：《Chinese Journal of Catalysis》2024年第6期281-290,共10页催化学报（英文）

基　　金：国家自然科学基金(11974303,12074332);江苏省青蓝工程(137050317);扬州大学高端人才计划(137080051);化学重点学科交叉研究基金(yzuxk202014).

摘　　要：电解水技术是一种生产高纯氢燃料的方法,能够增强可再生能源发电系统的消纳能力.相较于质子交换膜(PEM)电解槽,碱性(ALK)电解槽可以使用非贵金属基催化电极,拥有更高的经济效益和市场占有率.然而,由于ALK电解槽处于质子稀缺环境,阴极氢气演化反应(HER)动力学变得更加复杂,需要快速解离水分子提供动态质子微环境.硫化钼(MoS_(2))纳米片边缘具有合适的质子吸附和演化的活性位点,是制备HER催化剂的潜力材料.但其二维基面原子由于配位饱和,显示出较弱的质子吸附能力.如何调控MoS_(2)基面以实现水解动力与质子吸附演化动力的集成,提升MoS_(2)纳米片的碱性HER活性,具有重要的科学和应用意义.本文提出了一种Co/O双原子植入策略,精准调控双活性位点及其电子结构,实现了水解离动力和质子吸附演化动力的高效耦联.首先,利用刻蚀和电沉积的两步实验法,在MoS_(2)基面上成功引入O和Co原子;随后,结合高分辨透射电镜、高角环形暗场-扫描透射电子显微镜、同步辐射X射线吸收精细结构谱等表征分析技术,精准识别了掺杂Co/O原子的位置和配位情况:O原子替换部分S原子,Co原子占据Mo原子的上方,构建出立体凸起的“O-Co-S_(2)”配位构型.催化在线的原位表征分析结果表明:该独特的“O-Co-S_(2)”原子基序发挥着水解离与氢演化反应协同催化效应.密度泛函理论计算结果也证实了该协同机制,其中Co位点促进水的解离反应,而S位点则有助于质子的转化生成氢气.因此,Co/O掺杂MoS_(2)催化剂(Co-O@MoS_(2))表现出较好的碱性HER活性:仅需81 mV的过电位,即可达到100 mA cm^(‒2)的电流密度,Tafel斜率低至42 mV dec^(‒1),在600 mA cm^(‒2)的高电流密度测试中运行300 h活性无衰减.上述碱性HER性能不仅远高于原始的MoS_(2)纳米片,而且也领先于部分已报道结果.综上所述,本文在MoS_(2)基面上构筑了原�Alkaline water electrolysis allows the adoption of non-precious metal catalysts,but increases the challenge of cathodic hydrogen evolution reaction(HER)with the proton-deficient environment.Here we report an“all-in-one”design by atomic-level tailoring on molybdenum sulfide(MoS_(2))basal planes with synergistic active centers to trigger water dissociation for proton supply and meanwhile improve proton adsorption for hydrogen evolution.The resultant Co/O-codoped MoS_(2)(Co-O@MoS_(2))catalyst shows superb alkaline HER activity with a small Tafel slope of 42 mV dec^(‒1)and an overpotential as low as 81 mV at 100 mA cm^(‒2),and considerable stability over 300 h even at industrial-grade high current density of 600 mA cm^(‒2),which are among the best records for precious-metal-free HER catalysts in alkaline media.The markedly enhanced alkaline HER performance is attributed to the synergistic effect from atomically constructed O-Co-S_(2)motifs with local electronic interactions,in which Co sites promote the premier water dissociation,and S sites facilitate proton transition to generate hydrogen,respectively.This work presents an atomic-scale structural modification to create synergistic active sites for alkaline HER and provides insights into the atomic activation engineering towards advanced catalysts.

关 键 词：碱水电解 氢气演化反应 硫化钼 原子尺度活化 协同活性位点 

分 类 号：TQ116.21[化学工程—无机化工] O643.36[理学—物理化学]