Caesium sites coordinated in Boron-doped porous and wrinkled graphitic carbon nitride nanosheets for efficient charge carrier separation and Transfer: Photocatalytic H-2 and H(2)O2 production

Abstract

This study reports the synthesis of a highly efficient visible-light-driven photocatalyst for hydrogen evolution and H2O2 production by manipulating the electronic band structure and surface properties of g-C3N4. Boron and caesium co-doped g-C3N4 porous and wrinkled nanosheets were nobly synthesized by using recrystallization of melamine in water in the presence of boric acid and CsCl followed by calcination and thermal etching. The prepared nanosheets showed an extremely porous and wrinkled structure with high surface area and edge sites. The optimized B, Cs co-doped g-C3N4 nanosheets exhibited a stable hydrogen evolution rate of 1,120 mu molg-1h-1 in the presence of triethanolamine, which is 7.7 times higher than that of the bulk. Moreover, this optimized structure showed a greatly increased hydrogen peroxide production rate of 113 mu molg-1h-1 compared to that (19 mu molg-1h- 1) of the bulk GCN-B. Meanwhile, the optimized structure showed a high photooxidation ability toward RhB oxidation. This outstanding improvement in photocatalytic performance is attributed to the enhanced charge carrier mobility in the pi-conjugated structure and increased accessible reaction sites for photocatalytic reactions originated from the synergetic effect of co-doping and formation of the porous and wrinkled nanosheets.