Preparation of CdS@CeO2 core/shell composite for photocatalytic reduction of CO2 under visible-light irradiation

摘要

Present work demonstrates fabrication of CdS@CeO2 core/shell composite and its application in the photocatalytic reduction of CO2 under visible-light irradiation (lambda >= 420 nm). CdS@CeO2 composite has been successfully prepared by two-step chemical method, while CeO2 and CdS have been synthesized by one-step hydrothermal method. X-ray diffraction analysis confirms the formation of fluorite cubic structure of CeO2 and cubic phase of CdS. High resolution transmission electron microscopy and scanning electron microscopy reveal the microsphere morphology of CdS, while CeO2 (shell) is in the form of spherical particles that surround the CdS (core) in case of the composite. X-ray photoelectron spectroscopy has been used to confirm the composition, oxidation state of the elements and valance band of the obtained materials. The CdS@CeO2 core/shell composite and CdS can convert CO2 into methane and methanol under visible-light irradiation. The CdS@CeO2 composite shows higher yield for both methane and methanol than CdS due to low recombination rate of photogenerated electron/hole pairs, as well as a larger BET specific surface area. Moreover, the CdS@CeO2 core/shell composite also shows improved stability upon photocatalysis. (C) 2016 Elsevier B.V. All rights reserved.