Lu Yao, Guo Yanzhen, Zhang Shao, Li Lejing, Jiang Ruibin, Zhang Dieqing, Yu Jimmy C, Wang Jianfang
Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR 999077, China.
Henan Provincial Key Laboratory of Nanocomposites and Applications, Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006, China.
ACS Nano. 2024 Jul 26;18(31):20435-48. doi: 10.1021/acsnano.4c04797.
Photocatalytic HO production has attracted much attention as an alternative way to the industrial anthraquinone oxidation process but is limited by the weak interaction between the catalysts and reactants as well as inefficient proton transfer. Herein, we report on a hydrogen-bond-broken strategy in carbon nitride for the enhancement of HO photosynthesis without any sacrificial agent. The HO photosynthesis is promoted by the hydrogen bond formation between the exposed N atoms on hydrogen-bond-broken carbon nitride and HO molecules, which enhances proton-coupled electron transfer and therefore the photocatalytic activity. The exposed N atoms serve as proton buffering sites for the proton transfer from HO molecules to carbon nitride. The HO photosynthesis is also enhanced through the enhanced adsorption and reduction of O gas toward HO on hydrogen-bond-broken carbon nitride because of the formation of nitrogen vacancies (NVs) and cyano groups after the intralayer hydrogen bond breaking on carbon nitride. A high light-to-chemical conversion efficiency (LCCE) value of 3.85% is achieved. O and HO molecules are found to undergo a one-step two-electron reduction pathway by photogenerated hot electrons and a four-electron oxidation process to produce O gas, respectively. Density functional theory (DFT) calculations validate the O adsorption and reaction pathways. This study elucidates the significance of the hydrogen bond formation between the catalyst and reactants, which greatly increases the proton tunneling dynamics.
光催化产生羟基自由基（·OH）作为一种替代工业蒽醌氧化工艺的方法已引起广泛关注，但因催化剂与反应物之间相互作用较弱以及质子转移效率低下而受到限制。在此，我们报道了一种在氮化碳中打破氢键的策略，用于在无任何牺牲剂的情况下增强·OH的光合成。·OH的光合成通过氢键断裂的氮化碳表面暴露的N原子与·OH分子之间形成氢键来促进，这增强了质子耦合电子转移，从而提高了光催化活性。暴露的N原子作为质子缓冲位点，用于质子从·OH分子转移到氮化碳。由于氮化碳层内氢键断裂后形成氮空位（NVs）和氰基，氢键断裂的氮化碳对O₂气体的吸附和还原增强，进而增强了·OH的光合成。实现了3.85%的高光化学转化效率（LCCE）值。发现O₂和·OH分子分别通过光生热电子经历一步双电子还原途径和四电子氧化过程以产生O₂气体。密度泛函理论（DFT）计算验证了O₂的吸附和反应途径。本研究阐明了催化剂与反应物之间形成氢键的重要性，这极大地增加了质子隧穿动力学。
