Efficient photoelectrochemical water oxidation of cobalt phthalocyanine decorated BiVO4 photoanode by improving kinetics

Highlights: • A simple method is developed to prepare CoPc(NH₂)₄/BiVO₄ composite photoanodes. • The PEC activity is optimized by varying the loading content of CoPc(NH₂)₄. • The improved kinetics contributes to the enhanced PEC activity. A simple method is developed to prepare cobalt phthalocyanine decorated BiVO₄ composite photoanodes (CoPc(NH₂)₄/BiVO₄). The photoelectrochemical (PEC) water oxidation activity of CoPc(NH₂)₄/BiVO₄ composite catalysts is optimized by varying the loading content of CoPc(NH₂)₄. Under 1 sun illumination, the optimized 2CoPc(NH₂)₄/BiVO₄ photoelectrode exhibits the largest photocurrent density of 3.02 mA/cm² at 1.23 V vs. RHE in this study, which is 2.7, 1.6 and 1.4 times that of pure BiVO₄, 1CoPc(NH₂)₄/BiVO₄ and 3CoPc(NH₂)₄/BiVO₄, respectively. The enhanced PEC water oxidation performance is ascribed to the synergistic effect between CoPc(NH₂)₄ and BiVO₄ by improving reaction kinetics. The present study indicates that there is an optimum concentration of CoPc(NH₂)₄ in the composite catalysts to maximize the PEC water splitting performance, highlighting the influence of the loading content of CoPc(NH₂)₄ on the oxygen evolution reaction.