Carbon-confinement modulated interfacial water structure for accelerated dissociation kinetics towards hydrogen evolution
Fanpeng Cheng * , Yue Yu , Yulu Wan , Dashuai Wang , Shangqing Chen , Jingfang Zhang , Huijuan Guo , Yang Xia , Yi Huang , Lijuan Shi , Liwei Cheng* , Qun Yi*
https://doi.org/10.1016/j.cej.2025.166181
Abstract：Low-cost and structurally tunable nickel sulfide is considered highly desirable electrocatalysts for alkaline hydrogen evolution reaction (HER). However, sluggish water dissociation, attributed to the unfavorable electrode-electrolyte dynamic interfacial water structure, limits the electrocatalytic performance. Herein, we construct carbon-confined Ni3S4 arrays (Ni3S4@C) by carbonization and subsequent etching step. Benefiting from the strong electron transferability and confinement effect, the Ni3S4@C shows improved HER performance, exhibiting the overpotentials of 49 and 415 mV to reach 10 and 1000 mA cm− 2, respectively, surpassing commercial Pt/C catalyst at higher current densities (>500 mA cm− 2). Characterization results uncover that the carbon layer triggered the generation of electron-rich Ni species due to the occurrence of electron transfer within Ni3S4@C. In-situ spectroscopy and calculated analyses indicate that the carbon-confined Ni3S4 modulates the interfacial water structure with abundant free water, preventing excessively robust hydrogen-bonding networks, which enables rapid water dissociation at Ni sites and optimal hydrogen adsorption energy at S sites for the boosted alkaline HER performance.
低成本且结构可调的硫化镍被认为是用于碱性析氢反应（HER）的极具前景的电催化剂。然而，由于电极-电解质动态界面水结构不利，导致水分解动力学缓慢，限制了其电催化性能。本文通过碳化和后续刻蚀步骤构建了碳限域的Ni₃S₄阵列（Ni₃S₄@C）。得益于优异的电子传输能力和限域效应，Ni₃S₄@C表现出增强的HER性能，达到10 mA cm⁻²和1000 mA cm⁻²电流密度时的过电位分别为49 mV和415 mV，在较高电流密度（>500 mA cm⁻²）下超越了商用Pt/C催化剂。表征结果揭示，由于Ni₃S₄@C内部发生电子转移，碳层促使了富电子Ni物种的生成。原位光谱和理论计算分析表明，碳限域的Ni₃S₄调控了界面水结构，使自由水含量增加，抑制了过于强健的氢键网络，从而实现了Ni位点上快速的水分解以及S位点上优化的氢吸附能，显著提升了碱性环境下的HER性能。
