Manipulation of Oxidation States on Phase Boundary via Surface Layer Modification for Enhanced Alkaline Hydrogen Electrocatalysis

• Published in: Advanced materials (Weinheim) 2024-12, Vol.36 (51), p.e2405128-n/a
• Main Authors: Huang, Huawei, Xu, Liangliang, Zuo, Shouwei, Song, Lu, Zou, Chen, García‐Melchor, Max, Li, Yang, Ren, Yuafu, Rueping, Magnus, Zhang, Huabin
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; alkaline hydrogen evolution; Amorphous materials; amorphous structure; Anion exchanging; Electrolysis; Electron states; Energy conversion; Energy of dissociation; heterostructure; Heterostructures; Hydrogen evolution reactions; Oxidation; Oxygen content; Phase boundaries; Surface layers; water splitting
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202405128

In alkaline water electrolysis and anion exchange membrane water electrolysis technologies, the hydrogen evolution reaction (HER) at the cathode is significantly constrained by a high energy barrier during the water dissociation step. This study employs a phase engineering strategy to construct heterostructures composed of crystalline Ni4W and amorphous WOx aiming to enhance catalytic performance in the HER under alkaline conditions. This work systematically modulates the oxidation states of W within the amorphous WOx of the heterostructure to adjust the electronic states of the phase boundary, the energy barriers associated with the water dissociation step, and the adsorption/desorption properties of intermediates during the alkaline HER process. The optimized catalyst, Ni4W/WOx‐2, with a quasi‐metallic state of W coordinated by a low oxygen content in amorphous WOx, demonstrates exceptional catalytic performance (22 mV@10 mA cm−2), outperforming commercial Pt/C (30 mV@10 mA cm−2). Furthermore, the operando X‐ray absorption spectroscopy analysis and theoretical calculations reveal that the optimized W atoms in amorphous WOx serve as active sites for water dissociation and the nearby Ni atoms in crystalline Ni4W facilitated the release of H2. These findings provide valuable insights into designing efficient heterostructured materials for energy conversion. A heterostructure of crystalline Ni4W and amorphous WOx is constructed through a phase engineering strategy. The oxidation state of W in WOx is adjusted to optimize the phase boundary properties with enhanced intrinsic activity for alkaline hydrogen evolution reaction process. This advancement is supported by operando X‐ray absorption spectroscopy and theoretical analysis, offering insights for designing more effective catalysts.