Influence of the synthesis method on CuWO4 nanoparticles for photocatalytic application

Abstract

The textile industry is responsible for most of the consumption and inappropriate disposal of organic and highly toxic pollutants, such as dyes. Therefore, it is necessary to remediate polluting molecules before returning the water to the environment. Photocatalysis is a promising method for dye molecule degradation as it can provide complete mineralization through an efficient photocatalytic process. CuWO4 exhibits a band gap of 2.40 eV and can be excited with visible light, making it economically advantageous for industrial-scale applications. In this work, CuWO4 was synthesized by coprecipitation (CM), microwave-assisted hydrothermal (HM), and polymeric precursor (PPM) methods to evaluate the photocatalytic behavior in response to the different characteristics obtained from the synthesis routes. In photocatalytic measurements for OH· radical generation, the sacrificial agent H2O2 was used, and in order to delay the recombination process sodium oxalate and silver nitrate scavengers were applied under visible light. CuWO4 synthesized by PPM was more efficient in the dye degradation when the Ag+ scavenger was used, indicating that the predominant reaction mechanism was by direct oxidation or hydroxyl radicals. The surface charge (− 38.5 (PPM), − 29.7 (CM), and − 16.2 mV (HM)) influence was more relevant than the specific surface area (1 (PPM), 22 (CM), and 21 m2 g−1 (HM)) of the samples in the photocatalytic process. The complete degradation occurred in 80 min for the samples obtained by CM and HM and only 20 min were necessary for the sample synthesized by PPM.