CoS@TiO2 S-scheme heterojunction photocatalyst for hydrogen production from photoinduced water splitting. (15th October 2021)

• Record Type: Journal Article
• Authors: Park, Hyerim; Kim, Seyeon; Kim, Taeseong; Kim, Youngsoo; Joo, Sang Woo; Kang, Misook
• Is Part Of: Journal of cleaner production. Volume 319(2021)
• Publication Date: 2021-10-15
• Subjects: Core-shell shaped catalyst -- Hydrogen production -- Strong redox sites -- S-Scheme charge transfer; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2021.128819
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: To synthesize durable catalysts, cobalt sulfide (CoS) microsheet particles are woven into a polyhedral cage shape to prevent dissolution and light corrosion during photochemical reactions. Titanium dioxide (TiO2 ) nanoparticles with excellent stability against water and light are used to enclose the cage. The surface of the dodecahedral CoS particle is positively charged, and the surface of the spherical TiO2 particles is negatively charged, resulting in a core–shell shaped xCoS@yTiO2 heterojunction particle. The xCoS@yTiO2 heterojunction catalyst has a stronger ability to absorb visible light and greater photocatalytic hydrogen evolution activity than pure TiO2 or CoS catalysts: When lactic acid is used as an electronic sacrificial agent, the hydrogen production of 1CoS@2TiO2 reaches 1945 μmol g −1 for 10 h, and the catalytic activities are 114.4 and 13.2 times those of CoS and TiO2, respectively. Spin-trapping ESR results reveal that charge transfer in the core–shell shaped xCoS@yTiO2 heterojunction follows the S-scheme mechanism. The excellent catalytic activity of the core–shell shaped xCoS@yTiO2 heterojunction catalyst is because of its favorable bandgap location for water splitting, higher photocurrent density, lower photoluminescence, and having strong redox sites. These factors ultimately delay the recombination of photo-induced electron/hole pairs and, as a result, high catalytic efficiency is stably maintained up to the fifth recycling test. Graphical abstract: Image 1 Highlights: ► A highly stable core–shell shaped CoS@TiO2 heterojunction was formed. ► CoS@TiO2 heterojunction exhibited favorable bandgap location and higher photocurrent densities, and lower photoluminescence. ► Photogenerated e − /h + recombination was slow and charge separation was more effective. ► Hydrogen production in 1CoS@2TiO2 heterojunction was 13.2 times that in pure TiO2 . ► Charge transfer in core–shell CoS@TiO2 heterojunctions followed the S-scheme mechanism.