Cu/Cu2O CORE-SHELL SUBMICRO/NANO CRYSTAL FOR Cr(VI) REDUCTION BY PHOTOCATALYSIS UNDER VISIBLE LIGHT

A method of reduction of Cr(VI) to Cr(III) under visible light was developed by using Cu/Cu2O core shell submicro/nano crystals,which were carried out by BET, XRD, XPS and TEM. Results showed that the catalyst was a complex composed of Cu2O and Cu with Cu2O as the predominant substance. The TEM result exhibited a typical core shell structure with Cu core and Cu2O-shell in dual-circinal shape. To reduce Cr(VI), an efficient photo catalytic cell (PC) was developed for using visible light with Cu/Cu2O core-shell submicro/nano crystal. The experiment was implemented in a cathode compartment with a fresh solution (150mL) of 10 mg/L Cr(VI) at three different pH values, 3.0, 7.0 and 12. At pH=3, around 91% of Cr(VI) was reduced after 60 h of reaction. The particular core-shell structure and the metal-metal oxide interaction significantly enhanced the visible-light-driven photocatalytic efficiency of the Cu/Cu2O core shell particles, since localized surface plasmon resonance (LSPR) of Cu may occur and radiate energy transfer from the plasmon Cu states to the oxide shell, which enabled the rate of electron excitation from the valence to conduction band of the Cu2O shell. In all, the work provides a potential way to reduce Cr(VI) to Cr(III) under visible light.