Remarkably enhanced H2 evolution activity of oxidized graphitic carbon nitride by an extremely facile K2CO3-activation approach

Abstract

The photocatalytic activity enhancement of graphitic carbon nitride (g-C3N4) in water splitting were commonly achieved by introducing various functional groups onto/into its planar structure. Herein, oxidized g-C3N4 (CNO) was prepared via an extremely facile K2CO3 activation approach. The high-resolution XPS spectra and solid-state 13C NMR spectra confirmed the successful introduction of O-containing groups and O atoms were inherited the original molecular framework of g-C3N4, but exhibited effectively enlarged bonded with C atoms rather than N atoms in the tri-s-triazine structure of g-C3N4. CNO inherited the original molecular framework of g-C3N4, but exhibited effectively enlarged surface area and enhanced visible light absorption, and more attrractively, the band structure of g-C3N4 could be well-tuned with the introduction of oxygen species. Importantly, the surface O-containing moieties could strongly interact with cocatalyst Pt and thus remarkably promote interfacial electron transfer and consequent photo-generated charge carrier separation. Consequently, the as-obtained CNO exhibited the remarkably enhanced photocatalytic performance with a H2 evolution rate of 199.7 μmol h−1, which is 9 times that of g-C3N4 (22.2 μmol h−1).