Interface-engineering derived WS2/S-g-C3N4 nanosheet Z-scheme heterostructures towards enhanced photocatalytic redox and H2O2 generation

Abstract

The growth of WS2 on S-doped graphic carbon nitrides (g-C3N4) was controlled to utilize horizontal implanting and get fine interfacial characteristic. Superior thin S-doped g-C3N4 nanosheets were fabricated via a two-step thermal polymerization at high temperature. Subsequent solvothermal procedure was used to create WS2/S-g-C3N4 (WS2/SCN) photocatalytic heterojunctions with optimized component ratios, in which doped S components in g-C3N4 play an important role for the horizontal growth and homogeneous distribution of WS2 nanosheets. Z-scheme charge transfer mechanism was proposed according to various characterizations. Photocatalytic rhodamine B (Rh B) degradation test indicated that WS2/SCN 15 % (sample WS2/SCN-3) revealed the best performance, in which Rh B of 92.8 % was photocatalytic oxidated with 20 min. Photocatalytic hydrogen generation experiments indicated that sample WS2/SCN-3 exhibited a H2 generation rate of 1380 μmol·g−1∙h−1, which was 3.7 times of that of S-g-C3N4 nanosheets. These WS2/S-g-C3N4 heterojunctions also exhibited excellent performance for photocatalytic H2O2 evolution. Sample WS2/SCN-3 exhibited a H2O2 generation rate of 5216 μmol·g−1·h−1 which was 6.4 times that of S-g-C3N4 sample. This excellent photocatalytic activity is scribed to WS2/S-g-C3N4 layered heterojunctions with well-developed interface characteristic. The result supplied an efficient approach for the preparation of photocatalysts.