n-n heterojunction CdS/FST photoanode for enhanced photoelectrochemical water splitting

Metal sulfides emerge as promising photoanode materials in photoelectrochemical (PEC) water splitting due to their suitable bandgaps and tunable properties through heterojunction formation. Herein, fibrous silica-titania (FST) was successfully prepared by the microemulsion method prior to the addition of cadmium sulfide (CdS/FST) via impregnation method, which then characterized by XRD, FESEM, SEM, TEM, N₂ adsorption-desorption, UV-vis/DRS, FTIR, and XPS. The result demonstrated that the photocurrent density of CdS/FST was 24.5 mA/cm^2, which is 1.5 times higher than that of FST (16.2mA/cm²). Insertion of CdS in the FST structure resulted in the strong interaction between CdS and FST, which then improved the utilization of photogenerated electrons, narrowed the band gap, and boosted the charge carrier separation. An n-n heterojunction was formed in CdS/FST, in which CdS acts as an electron donator in order to enhance the photogenerated electron of FST, hence improving the PEC water splitting performance. Introducing CdS into the FST configuration proved to be a highly effective strategy for crafting a superior photoanode tailored for PEC water splitting.