A novel pathway toward efficient and stable C3N4-based photocatalyst for light driven H2 evolution: The synergistic effect between Pt and CoWO4

Abstract

A photocatalytic integrated system containing Pt nanoclusters, CoWO4 nanoclusters and C3N4 nanosheets was achieved through a hydrothermal process followed by photodeposition. Meanwhile, the photocatalytic activity of the as-prepared system was explored for light driven H2 evolution. Finally, the photocatalytic mechanism was explored roughly. The results show that there exists strong synergistic effect between Pt and CoWO4. The photocatalytic activity of C3N4 can be significantly enhanced utilizing the aforementioned synergistic effect. When the as-prepared photocatalytic system is used, the fastest evolution rate of H2 can be up to 14.2 μmol h−1, which is 2.1 times as high as that over the Pt modified C3N4 nanosheets (6.7 μmol h−1). And the quantum yield of the as-prepared photocatalytic system at 400 nm (0.018%) is also much higher than that of the Pt modified C3N4 nanosheets (0.004%). Here, this remarkable photocatalytic activity ought to be attributed to superior separation of the electro-hole pair caused by efficient charge transfer in the photocatalytic system which follows a Z-scheme-like mechanism. Therein, Pt nanoclusters may serve as an electron transfer pathway between CoWO4 and C3N4 as well as active sites while CoWO4 nanoclusters may play a water oxidation cocatalyst.