Amine‐Rich Hydrogels Enhance Solar Water Oxidation via Boosting Proton‐Coupled Electron Transfer. Issue 5 (4th December 2022)

• Record Type: Journal Article
• Authors: Bae, Sanghyun; De Guzman, Rod Alexei Fitrian; Jeon, Dasom; Kim, Minjung; Ryu, Jungki
• Is Part Of: Advanced materials interfaces. Volume 10:Issue 5(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-04
• Subjects: hydrogel -- photoanodes -- photoelectrochemical water oxidation -- polyethyleneimine -- proton‐coupled electron transfer; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202202101
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Photoelectrochemical (PEC) water oxidation is a highly challenging task that acts as a bottleneck for efficient solar hydrogen production. It is because each cycle of water oxidation is composed of four proton‐coupled electron transfer (PCET) processes and conventional photoanodes and cocatalysts have limited roles in enhancing the charge separation and storage rather than in enhancing catalytic activity. In this study, a simple and generally applicable strategy to improve the PEC performance of water oxidation photoanodes through their modification with polyethyleneimine (PEI) hydrogel is reported. The rich amine groups of PEI not only allow the facile and stable modification of photoanodes by crosslinking but also contribute to improving the kinetics of PEC water oxidation by boosting the PCET. Consequently, the PEC performance of various photoanodes, such as BiVO4, Fe2 O3, and TiO2, is significantly enhanced in terms of photocurrent densities and onset potentials even in the presence of notable cocatalyst, cobalt phosphate. The present study provides new insights into and strategies for the design of efficient photoelectrodes and PEC devices. Abstract : Amine‐rich hydrogel‐modified photoanodes exhibit enhanced photoelectrochemical water oxidation activity. The amine groups in hydrogel assist proton migration and stabilization of *OH intermediate, promoting water oxidation process thermodynamically. Enhanced proton‐coupled electron transfer process results in highly improved onset potentials and photocurrents, and this simple modification is suggested as a novel alternative to be universally applicable to improve water oxidation.