Probing Photocorrosion Mechanism of CdS Films and Enhancing Photoelectrocatalytic Activity via Cocatalyst

CdS has unstability due to its severe photocorrosion, which restricts its further application in photoelectrocatalysis. In this paper, after probing detailedly the photocorrosion mechanism that is the oxidation caused by photogenerated holes of CdS, NiOOH cocatalyst is employed to heighten its stability. The stability of CdS/NiOOH is improved 44.50% higher than that of pure CdS after photoelectrochemical (PEC) stability test for 3600 s, because the NiOOH prevents the oxidation of the CdS via capturing the photogenerated holes. Meanwhile, the deposition of NiOOH is beneficial to accelerate the separation of photogenerated carriers, thereby enhancing the PEC activity. The results show that the CdS/NiOOH photoanode achieved a photocurrent density of 3.70 mA cm−2 at 1.23 V vs. RHE, which is approximately 2.03 folds than that of pure CdS. This work provides a simple and feasible method for boosting PEC activity and stability of CdS-based photoelectrode for efficient PEC water splitting.