Design, fabrication, electro- and photoelectrochemical investigations of novel CoTiO3/CuBi2O4 heterojunction semiconductor: An efficient photocatalyst for the degradation of DR16 dye

Abstract

In this study, design and preparation of a novel heterojunction nanocomposites based on CoTiO3 and CuBi2O4 noted as CoTiO3/CuBi2O4 is reported with the aid of a facile and eco-friendly synthesis approach. This study is the first attempt on the employing of CoTiO3/CuBi2O4 semiconductor for the photocatalytic degradation of organic dye. To confirm and address the straightforward synthesis of CoTiO3, CuBi2O4 and CoTiO3/CuBi2O4 heterojunction nanostructures different characterization techniques including XRD, DRS, FT-IR, FESEM, EDX, and ICP-OES are utilized. The BET is used to calculate the specific surface area from the N2 physisorption isotherm. The prepared CoTiO3/CuBi2O4 was used for the photocatalytic degradation of Direct Red16 dye under LED visible light irradiation. Accordingly, different experimental conditions were evaluated for the photocatalytic degradation of DR16 dye over prepared catalysts. Based on the obtained results CoTiO3/CuBi2O4 heterojunction nanocomposites in pH = 4.3 and loading of 5 g/L showed the highest removal efficiency. Hence, the superior photocatalytic performance of the CoTiO3/CuBi2O4 heterojunction is due to the efficient separation of electron-hole pairs, compatible junction formation, visible light absorption ability, suitable band gap and large amount of light harvesting. Mott-Schottky, Nyquist and Bode plots have been studied. Current in the light was higher than that in the dark indicating the efficient formation of photocurrent. According to the trapping experiments h+ was found as the main active species in the photocatalytic degradation mechanism. Moreover, the synthesized CoTiO3/CuBi2O4 heterojunction could be reused four times without noticeable loss of activity.