Hexagonal CdS photoanode modified with Pt and cobalt phosphate cocatalyst for efficient photoelectrochemical performance

Abstract The recombination of electron-hole pairs and the slow surface catalytic reactions have been deemed as the core problem affecting the efficiency of photoelectrochemical (PEC) performance. Here we synthesized hexagonal CdS photoanode on FTO substrate by hydrothermal method. Cobalt-phosphate (Co-Pi) and Pt cocatalysts were simultaneously decorated on the inner and outer surfaces of CdS (denoted as Pt/CdS/Co-Pi), which showed efficient charge separation/transfer performance on account of trapping the electrons with Pt and transferring holes with Co-Pi. As a result, the Pt/CdS/7.5Co-Pi photoanode showed a maximum photo-current of 5.05 mA/cm−2 at 0.28 V vs RHE under solar simulated illumination, which was 8.3 times higher than that of pure CdS photoanode. This work presents a promising guideline to design and fabricate an eco-friendly and sunlight-driven photoanode for the PEC water-splitting system.