Strategy of nitrogen defects sponge from g-C3N4 nanosheets and Ni-Bi-Se complex modification for efficient dye-sensitized photocatalytic H2 evolution

Abstract

An available strategy of nitrogen defects sponge from g-C3N4 nanosheets is successfully designed and the nitrogen defective ultrathin graphitic-phase (g-C3N4) nanosheets are properly prepared. Moreover, a layer of Ni-Bi-Se complex is effectively modified on the basis of appropriate nitrogen defective ultrathin graphitic-phase (g-C3N4) nanosheets and a more efficient dye-sensitized photocatalytic H2 evolution is obtained. In addition, in need of special note is that the density of nitrogen defects on g-C3N4 photocatalyst can be controlled and adjusted by means of barium hydroxide dosage. Besides the high H2 yield, the Ni-Bi-Se complex modified nitrogen defective ultrathin graphitic-phase (g-C3N4) nanosheets are very stable in the process of photocatalytic hydrogen production. A series of characterization studies such as SEM, XRD, TEM, EDX, XPS, UV–vis DRS, FTIR, transient fluorescence and electro-chemistry etc. show that the more active sites appears and the efficiency of photo-generated charge separation is improved due to the introduction of surface N vacancies and Ni-Bi-Se complex doping. The results of which is well mutual corroboration with each other. Based on above results, a possible reaction mechanism was proposed too.