Breaking through water-splitting bottlenecks over carbon nitride with fluorination

• DOI: 10.1038/s41467-022-34848-8
• Publication Date: 2022-11-16T12:03:43Z
• Authors: Ji Wu; Zhonghuan Liu; Xinyu Lin; Enhui Jiang; Shuai Zhang; Pengwei Huo; Yan Yan; Peng Zhou; Yongsheng Yan
• Keywords: Science; Q; 7. Clean energy; 01 natural sciences; Article; 0104 chemical sciences

AbstractGraphitic carbon nitride has long been considered incapable of splitting water molecules into hydrogen and oxygen without adding small molecule organics despite the fact that the visible-light response and proper band structure fulfills the proper energy requirements to evolve oxygen. Herein, through in-situ observations of a collective C = O bonding, we identify the long-hidden bottleneck of photocatalytic overall water splitting on a single-phased g-C3N4 catalyst via fluorination. As carbon sites are occupied with surface fluorine atoms, intermediate C=O bonding is vastly minimized on the surface and an order-of-magnitude improved H2 evolution rate compared to the pristine g-C3N4 catalyst and continuous O2 evolution is achieved. Density functional theory calculations suggest an optimized oxygen evolution reaction pathway on neighboring N atoms by C–F interaction, which effectively avoids the excessively strong C-O interaction or weak N-O interaction on the pristine g-C3N4.