Spectroscopic Study on CdS/Ni/KNbO₃: Confirming Ni Effect to Photocatalytic Activity

Herein, we report the structural and photophysical properties of CdS/Ni/KNbO₃ composites with a quantum yield for photocatalytic H₂ generation that is CdS and Ni amount dependent. The nonstoichiometric KNbO₃ (1:1.1) structure indicates the defect at the K site, which is Ni-occupied during its deposit process. It exhibits a tendency like a Ni-doped characteristic up to 0.1 wt % Ni and then forms a Ni cluster in case the Ni amount exceeds 0.1 wt %. The related structural and photophysical properties of CdS/Ni/KNbO₃ are examined with Fourier transform infrared, X-ray diffraction, ultraviolet-visible absorption, and luminescence spectral analysis. It demonstrates the CdS/Ni/KNbO₃ composites to be an efficient light conversion caused by efficient charge/electron transfer between KNbO₃ and CdS via doped Ni. The photocatalytic activity of CdS/Ni/KNbO₃ exhibits a CdS and Ni amount dependency. The best photocatalytic activity for H₂ generation is obtained with 0.1 wt % Ni and 2.9 wt % CdS as it gradually declines with the excess Ni amount than 0.1 wt % caused by a formed Ni cluster.