Preparation of SnO2/conjugated polyvinyl alcohol derivative nanohybrid with good performance in visible light-induced photocatalytic reduction of Cr(VI)

A new visible light-responsive SnO2/conjugated polyvinyl alcohol derivative (CPVA) nanohybrid photocatalyst was prepared by an easy-to-implement three-step method, using low cost and easily accessible SnCl4·5H2O, PVA and H2O as the source materials. The photocatalytic properties of the as-prepared SnO2/CPVA nanohybrid were examined through the reduction of aqueous Cr(VI) in the presence of citric acid and visible light (λ > 420 nm). The compositional and structural analysis of SnO2/CPVA nanohybrid after the recycle stability test was also performed. The photodegradation efficiency of Cr(VI) using SnO2/CPVA nanohybrid and other reported visible light-responsive photocatalysts (g-C3N4 and ZnFe2O4/CPVC nanocomposite) were compared. Besides, the effects of the solution pH and different water matrices (including black chromium electroplating solution, industrial cooling water, yellow sea water, and tap water) on the efficiency of photocatalytic reduction of Cr(VI) by SnO2/CPVA nanohybrid were also investigated. The results manifested that the as-prepared SnO2/CPVA nanohybrid had both high activity and good stability in photocatalytic reduction of aqueous Cr(VI) under visible light irradiation. According to the results of photoabsorption, photoluminescence, transient photocurrent response, electrochemical impedance, and Mott-Schottky characterization, it was deduced that the notable visible light-activated photocatalysis of SnO2/CPVA nanohybrid may originate from its prominent visible light-absorbing ability and the efficient electron transfer from CPVA to SnO2 (which results in the efficient separation of photoinduced charge carriers of CPVA as well as the sensitization of SnO2).