A CZS-decorated Al-MOF S-scheme heterojunction for concurrently photocatalytic generating H2 and Methylene Blue degradation under visible-light

Abstract

Photocatalytic hydrogen production coupled with the degradation of dye wastewater is deemed a promising strategy to overcome the challenges of both the energy crisis and water pollution. Herein, a novel heterojunction photocatalyst was constructed by decorating Cd0.5Zn0.5S (CZS) on the surface of the flower-shaped Al-MOF. It has confirmed that the internal-built electric field (IEF) at the interface between Al-MOF and CZS forced an S-scheme photoelectron transfer from the conduction band of Al-MOF to the valence band of CZS, thereby enhancing the photocarrier separation and boosting the photocatalytic efficiency of H2 evolution and methylene blue (MB) degradation. Al-MOF/0.3-CZS was demonstrated to have remarkable activity, over which the H2 amount generated in 4 h reached 17049.93 μmol g–1, the highest H2 generation rate of Al-MOF-based photocatalysts to date, when choosing lactic acid as the hole sacrificial agent and concurrently nearly 100% of MB could be degraded in 1 h under the visible light irradiation. Of note, when integrating the oxidation and reduction process as a whole, the high hydrogen production activity was still maintained (16028.6 μmol g–1), but the degradation efficiency of MB slightly decreased to 74.3%. During the coupled redox process, accompanied by the degradation of MB, MB also undertook the responsibility of photosensitizer. This work provided a valuable strategy for simultaneous H2 production and treatment of dye wastewater and extended the application boundary of Al-MOF-based materials.