Study on cobalt-phosphate (Co-Pi) modified BiVO4/Cu2O photoanode to significantly inhibit photochemical corrosion and improve the photoelectrochemical performance

Abstract

The serious recombination of photogenerated carriers and the photochemical corrosion of the electrode extremely restricted its photoelectrochemical (PEC) performance, which could not reach the theoretical photocurrent intensity. However, so far, there are few comprehensive reports on the mechanism of corrosion inhibition and stability improvement of electrodes in photocatalytic degradation. In this paper, BiVO4/Cu2O heterojunction modified by Cobalt-phosphate (Co-Pi) co-catalyst was successfully prepared to address the aforementioned issues. Co-Pi completed the holes capture and release process through the change of its own chemical state (Co2+/3+→Co4+→Co2+/3+), and also affected the energy band bending of the BiVO4/Cu2O heterojunction. In addition, the effect mechanism of the Co-Pi film thickness on the PEC performance of the photoanode was systematically discussed in this report. When the deposition amount was 0.05C∙cm−2, the photocurrent density reached 2.22 mA∙cm−2 at 1.23 V (vs. RHE), which was 2.8 times that of bare BiVO4. The LSV curves, EIS and UV–vis absorption spectra reveal the enhanced PEC performance and light stability of the prepared electrode materials. When it is applied to photocatalytic degradation of organic pollutants, BiVO4/Cu2O/0.05Co-Pi shows high activity and potential for MB and CIP degradation, and is expected to be stably applied to the field of photocatalytic degradation of refractory organic pollutants in water.