Pt co-catalyst effect on photoelectrochemical properties of 3C-SiC photo-anode

The effect of Pt co-catalyst fabricated with various annealing temperatures on photoelectrochemical (PEC) properties of 3C-SiC photo-anode was investigated. 3C-SiC with Pt co-catalyst shows the greater PEC reaction compared with bare 3C-SiC. A further enhancement is found by annealing process due to the Pt particle structure and enhanced contact of 3C-SiC and Pt. The formation of Pt particles improves the PEC reaction of samples annealed at 500 and 700 °C. Here, 3C-SiC with the Pt annealed at 500°C shows the largest photocurrent, 3.47 mA/cm² at an applied bias of 1V (vs Ag/AgCl) and the lowest onset potential, 0.74V with the optimum particle size. It is also considered to have appropriate contact by the proper Pt₂Si formation, revealed by X-ray photoelectron microscopy. Although photocurrent is improved after anneal at 700°C, the onset potential becomes almost same as bare 3C-SiC. Furthermore, the photo-activity after anneal at 900°C is even degraded compared to the bare 3C-SiC because of the evolution of immoderate carbon compounds suppressing Pt co-catalyst effect.