1. College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, China;2. State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China;3. University of the Chinese Academy of Sciences, Beijing 100049, China;4. Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou 350108, China
Abstract:
Visible-light-driven photocatalytic H2 evolution coupled with oxidative organic synthesis is attracting extensive attention owing to the environmental friendliness and sustainability of these processes, which can coproduce clean H2 fuel and high-value chemicals under mild conditions without requiring sacrificial agents. Semiconductor materials and metal-organic framework (MOF) materials have been widely used in photocatalys owing to their properties and advantages. In this work, we successfully synthesized a novel effective catalyst (named CdS/PFC-8) by electrostatic self-assembly. Among the components of the CdS/PFC-8 composite, PFC-8 was a nickel-based MOF. The CdS/PFC-8 composite, as a noble metal-free catalyst, enabled excellent photocatalytic H2 evolution and benzyl alcohol oxidation under visible light. A series of catalytic characterizations were performed with the CdS/PFC-8 composite. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results demonstrated the successful synthesis of the CdS/PFC-8 composite. X-ray photoelectron spectroscopy (XPS) results demonstrated the existence of an interfacial interaction between CdS nanorods and PFC-8. The optoelectronic performance was characterized by ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence (PL) spectroscopy, and electrochemical tests, and the results demonstrated the visible-light response and photocatalytic feasibility of the CdS/PFC-8 composite. The photocatalytic results obtained with different catalysts were compared. Under visible light, the CdS/PFC-8 composite enabled the generation of H2 with the selective oxidation of benzyl alcohol in a single reaction. It exhibited a remarkable H2 production rate of 3376 μmol∙g-1∙h-1; further, the benzaldehyde yield was 4120 μmol∙g-1∙h-1, which is higher than that of CdS alone. Photocatalytic cycling reactions were carried out to verify the activity and stability of the catalysts. The changes in the catalysts before and after the reaction were analyzed, and the results suggested that the nickel in PFC-8 could be used as a catalytically active site to improve the catalytic activity. In addition, the possible photocatalytic reaction mechanism was discussed. This work highlights the advantages of combining the functionalities of semiconductors and MOFs to enhance the photocatalytic activity.
