Wu Chongbei, Teng Zhenyuan, Yang Chao, Chen Fangshuai, Yang Hong Bin, Wang Lei, Xu Hangxun, Liu Bin, Zheng Gengfeng, Han Qing
Key Laboratory of Cluster Science, Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Department of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
Department of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu, 804-8550, Japan.
Adv Mater. 2022 Jul;34(28):e2110266. doi: 10.1002/adma.202110266. Epub 2022 Jun 5.
Two-electron oxygen photoreduction to hydrogen peroxide (H O ) is seriously inhibited by its sluggish charge kinetics. Herein, a polarization engineering strategy is demonstrated by grafting (thio)urea functional groups onto covalent triazine frameworks (CTFs), giving rise to significantly promoted charge separation/transport and obviously enhanced proton transfer. The thiourea-functionalized CTF (Bpt-CTF) presents a substantial improvement in the photocatalytic H O production rate to 3268.1 µmol h g with no sacrificial agents or cocatalysts that is over an order of magnitude higher than unfunctionalized CTF (Dc-CTF), and a remarkable quantum efficiency of 8.6% at 400 nm. Mechanistic studies reveal the photocatalytic performance is attributed to the prominently enhanced two-electron oxygen reduction reaction by forming endoperoxide at the triazine unit and highly concentrated holes at the thiourea site. The generated O from water oxidation is subsequently consumed by the oxygen reduction reaction (ORR), thereby boosting overall reaction kinetics. The findings suggest a powerful functional-groups-mediated polarization engineering method for the development of highly efficient metal-free polymer-based photocatalysts.
两电子氧光还原生成过氧化氢（H₂O₂）因其缓慢的电荷动力学而受到严重抑制。在此，通过将（硫）脲官能团接枝到共价三嗪骨架（CTF）上，展示了一种极化工程策略，从而显著促进了电荷分离/传输，并明显增强了质子转移。硫脲功能化的CTF（Bpt-CTF）在无牺牲剂或助催化剂的情况下，光催化H₂O₂产率大幅提高至3268.1 µmol h⁻¹ g⁻¹，比未功能化的CTF（Dc-CTF）高出一个数量级以上，并且在400 nm处具有8.6%的显著量子效率。机理研究表明，光催化性能归因于通过在三嗪单元形成内过氧化物以及在硫脲位点高度集中空穴，显著增强了两电子氧还原反应。水氧化产生的O₂随后被氧还原反应（ORR）消耗，从而加快了整体反应动力学。这些发现为开发高效无金属聚合物基光催化剂提出了一种强大的官能团介导的极化工程方法。
