Novel Zn0.8Cd0.2S@g-C3N4 core-shell heterojunctions with a twin structure for enhanced visible-light-driven photocatalytic hydrogen generation

摘要

A series of novel core-shell nanocomposites composed of twinned nanocrystal Zn0.8Cd0.2S solid solution and porous g-C3N4 nanosheets were fabricated by a combined ultrasonication and solvothermal method. The photocatalytic hydrogen production activities of these samples were evaluated without a co-catalyst in water under visible light irradiation ( 420 nm). It is found that the H-2 production rate of the Zn0.8Cd0.2S@g-C3N4-10 wt% sample was 2351.18 mol h(-1) g(-1), which is 146.0 and 5.7 times higher than that of pristine porous g-C3N4 nanosheets and Zn0.8Cd0.2S solid solution. Further detailed characterization reveals that the drastically enhanced and stable light-to-hydrogen energy conversion can be attributed to not only the efficient spatial separation of the photo-induced electrons and holes resulted from the synergetic effects of twinned homojunctions and core-shell heterojunctions, but also the intimate contact at the molecular scale between the porous g-C3N4 shell and Zn0.8Cd0.2S core. Therefore, this work puts forward a promising way to obtain unique core-shell heterojunctions with excellent stability and activity during a photoreaction process.