A comprehensive study of the influence of sulfonated graphene sheets and CdS nanoparticles on the photocatalytic degradation and hydrogen evolution activities of TiO 2 nanospheres

Lack of clean water and energy crisis remains worldwide challenges. Preparation of efficient photocatalysts have been demonstrated to be a promising approach for environmental remediation and renewable energy production. In this work, sulfonated graphene oxide (SGO)-TiO2-CdS (STC) multi-component composites were delicately designed and synthesized through the hydrothermal method combining with two-phase mixing process. The influences of SGO sheets and CdS nanoparticles on the photodegradation and hydrogen evolution performances of TiO2 nanospheres were studied thoroughly. The photodegradation and hydrogen evolution efficiency of STC composites were significantly improved in the presence of SGO and CdS as co-catalysts. STC-5 with the highest hydrogen evolution rate (15.835 mmol·g-1·h-1) can generate 3167 µmol H2 within 120 min, which is much higher than that of SGO-TiO2, TiO2-CdS, and SGO-CdS. SGO sheets and CdS nanoparticles can improve light absorption and reduce charge recombination rate of TiO2 nanospheres concurrently, which were confirmed by analyses of UV-vis spectra, PL spectra and electrochemical measurements. The intrinsic superior properties of STC composites contributes to the excellent photodegradation and hydrogen evolution activities. Hence, this study creates a rational avenue for fabrication of multi-component composites and their applications in the industrial fields of wastewater purification and clean energy production.