N2 plasma assisted surface modification of g-C3N4 nanosheets for enhanced photocatalytic H2O2 production

Abstract

Artificial photosynthesis of H2O2 is an environmental-friendly, sustainable and cost-effective approach to achieve scalable solar fuel production, which only utilizes water and oxygen as the source materials, renewable solar energy as energy supply. Efficient synthesis and soft surface modification of nanomaterials are of great importance to realize high photocatalytic H2O2 production performance. Herein, a two-step calcination strategy is applied to obtain ultrathin g-C3N4 nanosheets, afterward, a facile microwave plasma with N2 as carrier gas is employed to modify the surface structure and pore structure of g-C3N4 nanosheets. High energy electrons and highly active free radicals from N2 plasma not only induce carbon vacancies, but also oxygen-containing functional groups, which can effectively modulate the energy levels, facilitate the interaction of water with catalyst, and meanwhile promote the separation and transfer of photogenerated charge carriers. After transient N2 plasma processing, the photocatalytic H2O2 generation of ultrathin g-C3N4 nanosheets shows remarkable improvement. This study indicates that plasma treatment is a rapid, mild, effective and promising strategy to modify nanomaterials for high photocatalytic performance.