Wang Zhenyu, Liu Rujia, Sun Tong, Li Mengrui, Ran Nian, Wang Dengchao, Wang Zonghua
College of Chemistry and Chemical Engineering, College of Materials Science and Engineering, Qingdao Application Technology Innovation Center of Photoelectric Biosensing for Clinical Diagnosis and Treatment, Shandong Sino-Japanese Centre for Collaborative Research of Carbon Nanomaterials, Qingdao University, Qingdao, Shandong 266071, China.
School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
Anal Chem. 2024 May 14;96(19):7618-7625. doi: 10.1021/acs.analchem.4c00515. Epub 2024 Apr 30.
The characterization of the heterostructure active sites during the hydrogen evolution reaction (HER) process and the direct elucidation of the corresponding catalytic structure-activity relationships are essential for understanding the catalytic mechanism and designing catalysts with optimized activity. Hence, exploring the underlying reasons behind the exceptional catalytic performance necessitates a detailed analysis. Herein, we employed scanning electrochemical microscopy (SECM) to image the topography and local electrocatalytic activity of 1T/2H MoS heterostructures on mixed-phase molybdenum disulfide (MoS) with 20 nm spatial resolution. Our measurements provide direct data about HER activity, enabling us to differentiate the superior catalytic performance of 1T/2H MoS heterostructures compared to other active sites on the MoS surface. Combining this spatially resolved electrochemical information with density functional theory calculations and numerical simulations enables us to reveal the existence of hydrogen spillover from the 1T MoS surface to 1T/2H MoS heterostructures. Furthermore, it has been verified that hydrogen spillover can significantly enhance the electrocatalytic activity of the heterostructures, in addition to its strong electronic interaction. This study not only contributes to the future investigation of electrochemical processes at nanoscale active sites on structurally complex electrocatalysts but also provides new design strategies for improving the catalytic activity of 2D electrocatalysts.
在析氢反应（HER）过程中对异质结构活性位点进行表征，并直接阐明相应的催化结构-活性关系，对于理解催化机理和设计具有优化活性的催化剂至关重要。因此，探究卓越催化性能背后的潜在原因需要进行详细分析。在此，我们采用扫描电化学显微镜（SECM）以20 nm的空间分辨率对混合相二硫化钼（MoS）上的1T/2H MoS异质结构的形貌和局部电催化活性进行成像。我们的测量提供了关于HER活性的直接数据，使我们能够区分1T/2H MoS异质结构与MoS表面其他活性位点相比的卓越催化性能。将这种空间分辨的电化学信息与密度泛函理论计算和数值模拟相结合，使我们能够揭示从1T MoS表面到1T/2H MoS异质结构存在氢溢流现象。此外，已证实氢溢流除了具有强大的电子相互作用外，还能显著提高异质结构的电催化活性。这项研究不仅有助于未来对结构复杂的电催化剂上纳米级活性位点的电化学过程进行研究，还为提高二维电催化剂的催化活性提供了新的设计策略。
