Construction of M-BiVO4/T-BiVO4 isotype heterojunction for enhanced photocatalytic degradation of Norfloxacine and Oxygen evolution reaction

[Display omitted] To conquer the issues of poor compatibility, confined intimate contact and limited improvement of charge anti-recombination process of a traditional heterojunction formed by interfacing of two different semiconductors, a simplistic strategy has been espoused for the fabrication of isotype heterojunction flanked with two dissimilar crystal phases of a single semiconducting material. Herein, we account the fabrication of an in-situ formed M-BiVO4/T-BiVO4 (MT-BiVO4) isotype heterojunction by a simple co-precipitation method followed by altering the calcinations temperatures. The physico-chemical properties of the fabricated MT-BiVO4 isotype hetrojunctions were analyzed by using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–Visible Diffuse reflectance spectroscopy (UV–Vis DRS) techniques. The FESEM image of MT-BiVO4 photodeposited by Au and MnOx particles was provided strong evidence for the spatial separation of photogenerated charge carriers between M and T phase of BiVO4 in an isotype heterojunction. The interfacing of T-BiVO4 with M-BiVO4 in an isotype heterojunction affords the well-built close contact between them was confirmed by the High resolution transmission electron microscopy (HRTEM) analysis. The photocatalytic reactions of all the prepared MT-BiVO4 isotype heterojunctions were examined by monitoring the degradation of Norfloxacine and oxygen evolution reaction under visible light irradiation. The optimized 65% MT-BiVO4 isotype heterojunction discloses higher photocatalytic activity around 91% of Norfloxacine degradation in 150 min and 808 µmol of O2 evolution in 2 h under visible light irradiation. On the other hand, the photoelectrochemical measurements reveals that the optimized 65% MT-BiVO4 isotype heterojunction exhibits superior photocurrent i.e. 584 µA/cm2 which is approximately 5.1 and 25.3 times higher than the neat T-BiVO4 and M-BiVO4, and these results are well consistent with the photocatalytic activities. The higher PEC and photocatalytic activities are due to the well-built close contact, superior compatibility and matching band structure between T-BiVO4 and M-BiVO4, which provides strapping driving force for the efficient enhancement of charge separation process. The Electrochemical impedance spectroscopy (EIS), photoluminescence (PL), photoelectrochemical (PEC) and bode analysis confirms the effec