Poliukhova, V. Khan, S. Qiaohong, Z. Zhang, J. Kim Doyeon Kim, Seung chul Cho, So Hye 2024-01-19T13:00:45Z 2024-01-19T13:00:45Z 2022-01-10 2022-02 0169-4332 https://pubs.kist.re.kr/handle/201004/115792 In this study, ZnS/ethylenediamine nanosheets were obtained by solvothermal synthesis and modified into composites of ZnS and ZnO by heat treatment. Compared to pure ZnO and ZnS, the ZnS/ZnO composite showed superior photocatalytic activity towards hydrogen evolution from water (500 ？mol h？1 g？1) and photoreduction of toxic Cr(VI) (k = 0.0078 min？1). Rietveld refined XRD patterns, high resolution-transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and UV？vis diffuse reflectance spectra (DRS) clearly showed that the composite forms a heterojunction structure instead of a solid solution of ZnS and ZnO. Density functional theory (DFT) modeling was conducted on a heterojunction interface and suggested that anion defects (S- and O-deficient) can allow Z-scheme photocatalysis to occur. The defect states in ZnS/ZnO composite were confirmed by XPS and electron paramagnetic resonance (EPR) measurement, suggesting the presence of oxygen vacancies. The defects create a deep energy state within bandgaps of ZnS and ZnO, which attracts holes from ZnS's valence band and electrons from ZnO's conduction band. Thereby electrons at the ZnS's conduction band and holes at ZnO's valence band are secured, allowing enhanced redox capability. ？ 2021 English Elsevier BV ZnS/ZnO nanosheets obtained by thermal treatment of ZnS/ethylenediamine as a Z-scheme photocatalyst for H2 generation and Cr(VI) reduction Article 10.1016/j.apsusc.2021.151773 1 Applied Surface Science, v.575 Applied Surface Science 575 Y scie scopus 000728026300006 2-s2.0-85118493090 Chemistry, Physical Materials Science, Coatings & Films Physics, Applied Physics, Condensed Matter Chemistry Materials Science Physics Article Chromium compounds Conduction bands Defects Electron spin resonance spectroscopy Electrons Heat treatment Heterojunctions High resolution transmission electron microscopy Hydrogen production II-VI semiconductors Nanosheets Paramagnetic resonance Photocatalytic activity Valence bands X ray photoelectron spectroscopy Zinc oxide Zinc sulfide % reductions Cr(VI) reduction Density functional theory Density-functional-theory Ethylene diamine H 2 production Z-scheme ZnO ZnO nanosheets ZnS/ZnO composite Density functional theory Cr(VI) reduction Density functional theory (DFT) H2 production Photocatalysis Z-scheme ZnS/ZnO composite