Synergistic oxygen substitution and heterostructure construction in polymeric semiconductors for efficient water splitting
Li Chen, Yuze Wang, Chongbei Wu, Guanhang Yu, Yue Yin, Chenliang Su, Jijia Xie, Qing Han, Liangti Qu
Abstract
Herein, we present a synergistic oxygen-substitution and heterostructure construction strategy to produce a two-dimensional oxygenated-triazine-heptazine-conjugated carbon nitride nanoribbon (TOH-CN). The TOH-CN was proved to have an internal donor-acceptor heterostructure that could promote interfacial charge separation and transport, while the oxygen substitution effect modulated the nanoribbon morphology with increased surface/edge active sites and tuned the electronic structure to extend visible-light absorption as well as to improve band structure alignment. Benefiting from these advantages, the TOH-CN served as an efficient bifunctional photocatalyst for both H2 and O2 evolution under visible-light irradiation, exhibiting a 16 times higher photocatalytic H2 evolution rate than that of its melon-based carbon nitride (g-C3N4) counterpart, and a remarkable apparent quantum yield of 7.9% at 420 nm. The O2 evolution rate was 6 times higher than that of g-C3N4, even much higher than those of most bifunctional carbon nitride-based photocatalysts. The developed synergistic strategy of oxygen substitution and heterostructure construction will provide an alternative route for the synthesis of efficient polymeric semiconductors toward efficient solar-to-chemical conversion.