Effect of conjugation degree and delocalized π-system on the photocatalytic activity of single layer g-C3N4

• Published in: Applied catalysis. B, Environmental Environmental, 2017-12, Vol.218, p.137-146
• Main Authors: Shi, Anye, Li, Huihui, Yin, Shu, Liu, Bin, Zhang, Jiachi, Wang, Yuhua
• Format: Article
• Language: English
• Subjects: Conjugation degree; Delocalized π-system; g-C3N4; Photocatalyst; Single layer
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2017.06.017

[Display omitted] Because of the superiority on conjugation degree and delocalized π-system, single layer g-C3N4-PAM exhibits excellent photocatalytic activity not only on organic degradation but also on H2 evolution. •Chemical exfoliation changes the surface electricity of g-C3N4.•The partial destruction occurred during acid exfoliation.•High conjugation degree was kept in g-C3N4-PAM.•Delocalized π-system was extended in g-C3N4-PAM.•g-C3N4-PAM exhibits higher photocatalytic activity. Single layer g-C3N4 could be obtained from a protonic acid treatment of g-C3N4 or a new sandwich-like orientation growth of melamine. Through the self-assembly of melamine and polyacrylamide by hydrogen bonds and electrostatic interactions, g-C3N4, with extended planarized atomic single layer, exhibits superiority in both photocatalytic hydrogen evolution and photocatalytic degradation under visible light irradiation. Besides low efficiency, the acid exfoliation will destroy the delocalized π-system by inducing O atoms. The decrease of conjugation degree increases the optical gaps, making it hard for g-C3N4 to capture photons. On the contrary, the facile sandwich-like orientation growth of melamine highly keeps the conjugation degree of g-C3N4 and extends its delocalized π-system. Such single layer g-C3N4 is more active even better than N-doped TiO2 under visible light irradiation.