Porous 2D Catalyst Covers Improve Photoelectrochemical Water‐Oxidation Performance

• Published in: Advanced materials (Weinheim) Vol. 36; no. 22; pp. e2211008 - n/a
• Main Authors: Xie, Guancai, Liu, Xiaolong, Guo, Beidou, Tan, Ting, Gong, Jian Ru
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.05.2024
• Subjects: 2D‐covered catalysts; Catalysis; Catalysts; Catalytic activity; Electrocatalysts; Graphene; Kinetics; Mass transfer; Oxidation; Photoanodes; photoelectrochemical water oxidation; porous graphene; Reaction kinetics; Silicon substrates; Structural stability; Thin films; Two dimensional materials; photoelectrochemical water oxidation; 2D‐covered catalysts; porous graphene
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202211008

Confined catalysis under the cover of 2D materials has emerged as a promising approach for achieving highly effective catalysts in various essential reactions. In this work, a porous cover structure is designed to boost the interfacial charge and mass transfer kinetics of 2D‐covered catalysts. The improvement in catalytic performance is confirmed by the photoelectrochemical oxidation evolution reaction (OER) on a photoanode based on an n‐Si substrate modified with a NiOx thin‐film model electrocatalyst covered with a porous graphene (pGr) monolayer. Experimental results demonstrate that the pGr cover enhances the OER kinetics by balancing the charge and mass transfer at the photoanode and electrolyte interface compared to the intrinsic graphene cover and cover‐free control samples. Theoretical investigations further corroborate that the pore edges of the pGr cover boost the intrinsic catalytic activity of active sites on NiOx by reducing the reaction overpotential. Furthermore, the optimized pores, which can be easily controlled by plasma bombardment, allow oxygen molecules produced in the OER to pass through without peeling off the pGr cover, thus ensuring the structural stability of the catalyst. This study highlights the significant role of the porous cover structure in 2D‐covered catalysts and provides new insight into the design of high‐performance catalysts. A porous graphene (pGr)‐covered NiOx electrocatalyst is designed to improve water oxidation of Si‐based photoanodes, compared to the intrinsic Gr cover and cover‐free counterparts. It is demonstrated that a pGr cover with optimized pore size balances the interfacial charge and mass transfer, ensures the structural stability of photoanodes, and enhances the intrinsic catalytic activity of active sites by reducing the reaction overpotential.