Materials Chemistry and Physics 307 (2023) 128081 Available online 27 June 2023 0254-0584/© 2023 Elsevier B.V. All rights reserved. Mn-doped ZnS nanoparticle photoanodes: Synthesis, structural, optical, and photoelectrochemical characteristics Hong Van Bui a , Dang Van Thai b, c , Tien Dai Nguyen b, d, * , Van Nang Lam e , Huu Toan Tran f , Van Manh Nguyen g , Nguyen Duc Nui h , Nguyen Manh Hung i a VNU University of Science, Vietnam National University, Hanoi, Viet Nam b Institute of Theoretical and Applied Research, Duy Tan University, Hanoi, 100000, Viet Nam c Faculty of Environmental and Chemical Engineering, Duy Tan University, Da Nang, 550000, Viet Nam d Faculty of Natural Sciences, Duy Tan University, Da Nang, 550000, Viet Nam e Department of Natural Sciences, Hoa Lu University, Ninh Nhat, Ninh Binh City, Viet Nam f Center for Post-Graduate Studies, Hanoi University of Industry, 298 Cau Dien, Bac Tu Liem, Hanoi, Viet Nam g Faculty of Chemical Technology, Hanoi University of Industry, Hanoi, 100000, Viet Nam h Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Viet Nam i Department of Materials Science and Engineering, Le Quy Don Technical University, Hanoi, 100000, Viet Nam HIGHLIGHTS G R A P H I C A L ABSTRACT • Mn:ZnS nanoparticles (NPs) (average crystal size of 2.8–3.8 nm) were suc- cessfully prepared by the co- precipitation method. • Pl spectrum of Mn:ZnS shows a strong emission peak at around 603 nm, assigned to the Mn 2+ band transition in the ZnS crystal. • Photocurrent of Mn:ZnS anode is 8.03 mA cm 2 at 0.4 V (vs. RHE), higher than ZnS using 0.5 M of electrolyte (Na 2 S + Na 2 SO 3 ). • The Mn:ZnS nanoparticles may have a high potential for future photo- electrochemical applications. A R T I C L E INFO Keywords: Mn-doped ZnS Nanoparticle Co-precipitation method Photoelectrochemical ABSTRACT In this work, Mn-doped zinc sulfde (Mn:ZnS) nanoparticles (NPs) have been synthesized as a promising material for photoelectrochemical water splitting (PEC), using the co-precipitation method. PEC properties of Mn-doped zinc sulfde NPs were considered under the correlation between Mn-doping level and their particle size. The highest photocurrent density (8.03 mA cm 2 ) and largest photoconversion effciency (0.63%) (at 0.4 V vs. RHE) were reached at 6 mol% Mn. Based on the results of used various materials characterization techniques, including transmission electron microscopy (TEM), X-ray diffraction, photoluminescence spectrum, and absor- bance spectrum, it can be assessed that the outstanding PEC characteristics of Mn:ZnS photoanode are attributed to the narrow bandgap of Mn:ZnS nanoparticles and their notably small particle size, which is originated from the Mn-doping. For application, the stability and the effect of various electrolytes were also investigated. * Corresponding author. Duy Tan University, Viet Nam. E-mail address: nguyentiendai@duytan.edu.vn (T.D. Nguyen). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys https://doi.org/10.1016/j.matchemphys.2023.128081 Received 6 April 2023; Received in revised form 6 June 2023; Accepted 16 June 2023