Bimetallic CoM-ZIF/CdS Photocatalyst Including Transition Metals(M) for Solar Water Splitting

Abstract

Recently, due to energy shortages and environmental pollution caused by the continued use of fossil fuels, there is a growing need for renewable sources to replace fossil fuels. ZIF-67 has a porous structure, a large surface area, high thermal and chemical stability, and a narrow band gap, so it is highly useful as a photocatalyst. In this study, the CoM-ZIF/CdS photocatalyst based ZIF-67 was synthesized using a chemical precipitation method synthesis with four different substances: Ni, Zn, Sn, and Cu. Field emission scanning electron microscopy analysis revealed that leaf-like particles are formed, and energy dispersive X-ray spectrometer analysis confirmed that CdS exists on the surface, as further evidenced by X-ray diffractometer analysis. The wurtzite CdS found in the optimized sample is considered the source of the higher photocatalytic activity. X-ray photoelectron spectroscopy detects all the elements included in the photocatalyst, with prominent peaks of Cd and S on the surface. UV-vis spectroscopy was used to analyze light absorbance. The band gap changed with various transition metals because the transition metal alters the energy level of the conduction band. The CoNi-ZIF/CdS photocatalyst exhibited the highest hydrogen production rate of 1192.9 µmol/g/h, with high reproducibility. The heterojunction between Co-ZIF and CdS reduces recombination. In conclusion, the synthesis of the CoM-ZIF/CdS photocatalyst results in a photocatalyst with a narrow band gap and an efficient charge separation mechanism.