Ultra-thin deaminated tri-s-triazine-based crystalline nanosheets with high photocatalytic hydrogen evolution performance

Abstract

Graphitic carbon nitride (g-CN) as a two-dimensional photocatalyst has received considerable attention. Tri-s-triazine-based crystalline carbon nitride nanosheets (CCN-nanosheets) with a thickness from 2 to 5 nm have been synthesized by a thermal procedure. The number of amino groups in the as-obtained samples significantly decreases compared with the samples before treatment (bulk-CCN), which optimizes the grain boundaries and narrows the band gap. Meanwhile, density functional theory (DFT) calculation demonstrates the distinct adjustment for the electronic structure of the sample from deamination. Combining the characteristics of two-dimensional morphology with high crystallinity, CCN-nanosheets demonstrates a high specific surface area of 154.2 m2 g−1, a suitable conductive band potential, improved photo-generated electron-hole pairs separation rate and high carrier transport efficiency. As a consequence, CCN-nanosheets exhibits an outstanding hydrogen evolution rate of 203 μmol h−1 (18 times higher than that of bulk-CCN and 20 times than that of pristine g-CN) and excellent cycling stability. It is anticipated that this facile and effective strategy for tailoring nanostructure and grain boundary would open up a new way for improving the photocatalytic performance of g-CN.