Enhanced photocatalytic water splitting over nickel-doped CdS nanocomposites synthesized via one-step controllable irradiation routine at ambient conditions

The work presents an ambient, facile, and controllable radiation-induced method to synthesize nickel-doped CdS (CdS-xNi) nanocomposites. We found that the optimized CdS-2Ni exhibited enhanced photocatalytic hydrogen (H2) evolution activity (∼3.86 mmol/g/h), which was three times that of pristine CdS-γ, and far superior to that of CdS-H (0.04 mmol/g/h) prepared by the conventional hydrothermal method. The analysis of transient photocurrent response, EIS, Mott-Schottky plot, PL, UV–vis, and TEM data, attributed the significant enhancement of photocatalytic activity to the sulfur vacancies and Ni active sites. We showed the ionizing radiation synthesis routine could alter the conduction band (CB) to be more negative and enable a stronger reduction capacity of electron-hole pairs. Furthermore, the doping of Ni induced the increase of sulfur vacancy and lattice distortion, which acted as the electron capture center of proton reduction and suppressed the electron transport, thereby efficiently separating the carriers and prolonging their lifetime. The radiation synthesis technology developed in this study provides a new path for the mild and controllable synthesis of high-performance photocatalysts.