Optimal fabrication of 0D/1D Cu2O quantum dots sensitized CdS nanorods heterojunction: Efficient photoredox catalyst for H2 generation under visible light irradiation

Abstract

Abstract The heterogeneous structure of Cu2O quantum dots (QDs) sensitized CdS nanorods (NRs) was synthesized by an easy and cost-effective technique. The morphology, structure and optical properties of as-prepared photocatalysts are thoroughly investigated by field emission gun scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (UVDRS) and photoluminescence (PL) spectroscopic techniques. The different weight percentages (10, 20, and 30) of Cu2O QDs deposited on the CdS NRs structures and their photocatalytic hydrogen (H2) evolution (PCHE) performance are systematically investigated. The Cu2O QDs deposition on CdS NRs shows an increase in the rate of hydrogen (H2) evolution due to the formation of type II heterojunction in between Cu2O QDs and CdS NRs. The 20% loading of Cu2O QDs on CdS exhibits the highest photocatalytic H2 generation than other ratios as well as pure Cu2O QDs and CdS NRs. The photocatalytic rate of H2 evolution of 26060 μmolg-1h-1 was obtained for 20 % Cu2O-CdS, which is18 times more than pure Cu2O QDs and 5.1 times than CdS NRs. Photoelectrochemical (PEC) measurements, electrochemical impedance spectroscopy, and photoluminescence measurements suggest that the Cu2O QDs deposition on CdS NRs reduces interfacial recombination of photogenerated charge carrier owing to the formation of the p-n junction between the components. The apparent quantum yield (AQY) obtained for 20 % Cu2O QDs modified CdS NRs photocatalysts is exceptionally high i.e. 20.67%. This convenient and cost-effective strategy will pave the way for large-scale synthesis of type II heterogeneous photocatalyst for efficient H2 evolution.