High performance long-afterglow phosphor-based ZnIn2S4/Sr2MgSi2O7:Eu2+,Dy3+ photocatalyst capable of dark state long-term application for photocatalytic sterilization

• Published in: Journal of alloys and compounds 2025-01, Vol.1010, p.176711, Article 176711
• Main Authors: Zhang, Hui, Sun, Mengmeng, Zhang, Jie, Zuo, Zeyu, Zhang, Ruiyong, Duan, Jizhou, Hou, Baorong
• Format: Article
• Language: English
• Subjects: Long afterglow luminescent materials; Marine sterilization materials; Photocatalytic sterilization; S-scheme heterojunction; Sustained sterilization
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.176711

Eco-friendly photocatalytic sterilization utilizing solar energy via the generation of reactive radicals excited by light irradiation devastating bacterial cells and mineralizing organic pollutants effectively exhibits vast application potential in marine biofouling prevention due to the abundant solar energy available in the ocean. Focusing on the issue of the cessation of photocatalytic processes in the absence of light, in this study, we selected the long afterglow material Sr2MgSi2O7:Eu2+,Dy3+ (SMSO), which exhibits persistent sky-blue luminescence after brief illumination, as the substrate for in situ compositing with the visible-light-responsive ZnIn2S4 (ZIS). The emission spectrum of SMSO partially overlaps with the absorption spectrum of ZIS, and their energy bands were well-matched. Consequently, the ZIS/SMSO=1:0.5 (mass ratio) exhibited the synergistic degradation and bactericidal performance under both light and dark conditions. ZIS/SMSO=1:0.5 exhibited the degradation rate of methyl orange (MO) of 72.4 % when exposed to 5 minutes of simulated sunlight, 2.6-fold increase compared to ZIS, and especially, it exhibited the sustained degradation rate of 38.7 % after 5 h in darkness. Besides, ZIS/SMSO=1:0.5 exhibited the bactericidal rate of 28.9 % under simulated visible light of 1 h, which was 2.9 and 2.5 times the bactericidal rate of ZIS and SMSO, respectively; and especially, after 6 h in darkness, it reached 64.4 %, which was 2.8 and 1.9 times the bactericidal rate of ZIS and SMSO, respectively. The Electron Spin Resonance (ESR) test validated the notably higher ·OH and ·O2- signals of the ZIS/SMSO=1:0.5 complex than those of individual components when exposed to light, and the sustained existence of ·OH signal even in darkness, revealing that the continuously generation of active free radicals even in the absence of light due to that the SMSO can continuously excite the ZIS. Combining with the in situ XPS analysis and the density functional theory calculations, an S-scheme heterojunction between ZIS and SMSO is formed which contribute to the higher yield of ·OH for ZIS/SMSO=1:0.5 under both light and dark conditions. And the calculation of the adsorption energies of ZIS and SMSO for O2 and OH- in the composite revealed that the ZIS component is more favorable for adsorbing O2, while the SMSO component is more favorable for adsorbing OH-. These analyses manifested the S-scheme electron transfer of the system. Finally, the ZIS/SMSO=1:0.5 composi