Wu Ji, Liu Zhonghuan, Lin Xinyu, Jiang Enhui, Zhang Shuai, Huo Pengwei, Yan Yan, Zhou Peng, Yan Yongsheng
Institute of Green Chemistry and Chemical Technology, School of Chemistry and Chemical Engineering, Jiangsu University, 212013, Zhenjiang, People's Republic of China.
Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA.
Nat Commun. 2022 Nov 16;13(1):6999. doi: 10.1038/s41467-022-34848-8.
Graphitic 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-CN 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 H evolution rate compared to the pristine g-CN catalyst and continuous O 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-CN.
长期以来，人们一直认为，尽管石墨相氮化碳具有可见光响应和合适的能带结构，满足了产生氧气所需的适当能量要求，但在不添加小分子有机物的情况下，它无法将水分子分解为氢气和氧气。在此，通过对集体C=O键的原位观察，我们通过氟化确定了单相g-CN催化剂上光催化全水分解长期隐藏的瓶颈。随着碳位点被表面氟原子占据，表面上的中间C=O键大大减少，与原始g-CN催化剂相比，析氢速率提高了一个数量级，并实现了持续的析氧。密度泛函理论计算表明，通过C-F相互作用，相邻N原子上的析氧反应途径得到优化，有效避免了原始g-CN上过强的C-O相互作用或较弱的N-O相互作用。
