Mo Zhao, Di Jun, Yan Pengcheng, Lv Chade, Zhu Xingwang, Liu Daobin, Song Yanhua, Liu Chuntai, Yu Qing, Li Huaming, Lei Yucheng, Xu Hui, Yan Qingyu
School of Materials Science and Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang, 212013, P. R. China.
School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
Small. 2020 Dec;16(48):e2003914. doi: 10.1002/smll.202003914. Epub 2020 Nov 9.
Direct water splitting over photocatalysts is a prospective strategy to convert solar energy into hydrogen energy. Nevertheless, because of the undesirable electron accumulation at the surface, the overall water-splitting efficiency is seriously restricted by the poor charge separation/transfer ability. Here, an all-organic donor-acceptor (D-A) system through crafting carbon rings units-conjugated tubular graphitic carbon nitride (C-TCN) is proposed. Through a range of characterizations and theoretical calculations, the incorporation of carbon rings units via continuous π-conjugated bond builds a D-A system, which can drive intramolecular charge transfer to realize highly efficient charge separation. More importantly, the tubular structure and the incorporated carbon rings units cause a significant downshift of the valence band, of which the potential is beneficial to the activation for O evolution. When serving as photocatalyst for overall water splitting, C-TCN displays considerable performance with H and O production rates of 204.6 and 100.8 µmol g h , respectively. The corresponding external quantum efficiency reaches 2.6% at 405 nm, and still remains 1.7% at 420 nm. This work demonstrates that the all-organic D-A system conceptualized from organic solar cell can offer promotional effect for overall water splitting by addressing the charge accumulation problem rooted in the hydrogen evolution reaction.
通过光催化剂直接分解水是将太阳能转化为氢能的一种前瞻性策略。然而，由于表面存在不良的电子积累，电荷分离/转移能力差严重限制了整体水分解效率。在此，我们提出了一种通过构建碳环单元共轭管状石墨相氮化碳（C-TCN）的全有机供体-受体（D-A）体系。通过一系列表征和理论计算，经由连续π共轭键引入碳环单元构建了一个D-A体系，该体系可驱动分子内电荷转移以实现高效的电荷分离。更重要的是，管状结构和引入的碳环单元导致价带显著下移，其电位有利于氧析出反应的活化。当用作整体水分解的光催化剂时，C-TCN表现出可观的性能，产氢和产氧速率分别为204.6和100.8 μmol g⁻¹ h⁻¹。在405 nm处相应的外量子效率达到2.6%，在420 nm处仍保持1.7%。这项工作表明，从有机太阳能电池概念衍生而来的全有机D-A体系，通过解决析氢反应中固有的电荷积累问题，可为整体水分解提供促进作用。
