One-step supramolecular preorganization constructed crinkly graphitic carbon nitride nanosheets with enhanced photocatalytic activity

Abstract

• Crinkly graphitic carbon nitride nanosheets are prepared by a one-step polycondensation process using urea and melamine as the precursors. • The conversion of urea to cyanuric acid during polycondensation enables the formation of melamine-cyanuric acid. • The obtained crinkly graphitic carbon nitride nanosheets exhibit much better optoelectronic properties compared to its bulk counterpart. • The photocatalytic hydrogen production rate of crinkly graphitic carbon nitride nanosheets is increased by 7 times. Here we report a new one-step thermal polycondensation process to form crinkly graphitic carbon nitride nanosheets (CGCNNs) via supramolecular preorganization, using a mixture of urea and melamine as the starting material. Systematical studies reveal that the newly developed CGCNNs significantly strengthen the optical absorption, widen the bandgap, and increase the Hall mobility and carrier density compared to that of its bulk counterpart, regardless of the similar chemical composition and structure. As a result, the photocatalytic hydrogen production rate is improved by 7 times. Moreover, Na doping of CGCNNs can further promote its photocatalytic activity, leading to an excellent photocatalytic hydrogen production rate of 250.9 µmol h –1 , which is approximately 10.5 times higher than its bulk counterpart. Moreover, an impressive apparent quantum efficiency of 19.12% is achieved at 420 nm. This study provides a facile strategy for the design of efficient low-cost carbon-nitride-based photocatalysts for solar fuel production.