Modification of Co3O4/CuBi2O4 photocatalyst for wastewater treatment

Abstract

Heterogeneous photocatalysis is an effective technology for the removal of organic dyes in textile wastewater. Metal oxide semiconductors have been extensively applied as photocatalysts in the last few decades. Herein, we report the synthesis of cobalt oxide (Co3O4), copper bismuth oxide (CuBi2O4) and Co3O4/CuBi2O4 composite powders by a co-precipitation method. The effect of Co3O4 addition on phase composition and microstructure of CuBi2O4 is studied using XRD, TEM and SEM. The surface area and pore structure of composite samples at different amounts of Co3O4 addition has been studied by nitrogen adsorption- desorption isotherm based on BET theory. Optical properties of the prepared photocatalyst are also investigated by DRS UV–Vis measurements. The intensity of photoluminescence (PL) is also used to measure of the electron hole recombination in the unmodified photocatalyst compared with the composite samples.

The photocatalytic activity of the prepared samples is evaluated under visible light with presence of methylene blue (MB) as target pollutant. Results show that coupling Co3O4 with CuBi2O4 could effectively promote photogenerated electron transfer in heterojunction, which is able to retard recombination process and thus improve their photocatalytic performance. In this system, 50 wt% Co3O4/CuBi2O4 exhibit the best photocatalytic activity in degrading 28% of MB within 120 min under visible irradiation.

Hence, the formation of a heterojunction between two photocatalysts is an efficient way to degrade the environmental pollutants in wastewater with the usage of photon energy, that can be further adapted for use in practical application.

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