ZnS/ZnO nanosheets obtained by thermal treatment of ZnS/ethylenediamine as a Z-scheme photocatalyst for H2 generation and Cr(VI) reduction

• DOI: 10.1016/j.apsusc.2021.151773
• Publication Date: 2021-11-01T16:22:02Z
• Authors: Valeriia Poliukhova; Sovann Khan; Zhu Qiaohong; Jinlong Zhang; Doyeon Kim; Seungchul Kim; So-Hye Cho
• Keywords: Ethylene diamine; Visible spectrum

In this study, ZnS/ethylenediamine nanosheets were obtained by solvothermal synthesis and modified into composites of ZnS ZnO heat treatment. Compared to pure ZnS, the ZnS/ZnO composite showed superior photocatalytic activity towards hydrogen evolution from water (500 µmol h−1 g−1) photoreduction toxic Cr(VI) (k = 0.0078 min−1). Rietveld refined XRD patterns, high resolution-transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS) clearly that forms a heterojunction structure instead solid solution ZnO. Density functional theory (DFT) modeling was conducted on interface suggested anion defects (S- O-deficient) can allow Z-scheme photocatalysis occur. The defect states in confirmed XPS paramagnetic resonance (EPR) measurement, suggesting presence oxygen vacancies. create deep energy state within bandgaps ZnO, which attracts holes ZnS's valence band electrons ZnO's conduction band. Thereby at are secured, allowing enhanced redox capability.