Engaging the flux-grown La1−xSrxFe1−yTiyO3 crystals in visible-light-driven photocatalytic hydrogen generation. (2nd November 2017)

• Record Type: Journal Article
• Authors: Hojamberdiev, Mirabbos; Kawashima, Kenta; Kumar, Mahesh; Yamakata, Akira; Yubuta, Kunio; Gurlo, Aleksander; Hasegawa, Masashi; Domen, Kazunari; Teshima, Katsuya
• Is Part Of: International journal of hydrogen energy. Volume 42:Number 44(2017)
• Page Start: 27024
• Page End: 27033
• Publication Date: 2017-11-02
• Subjects: LaFeO3 -- Perovskite -- Flux growth -- Photocatalyst -- Water splitting -- Hydrogen; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.09.036
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Perovskite LaFeO3 is regarded as one of the promising photocatalysts for solar splitting of water to hydrogen and oxygen due to its suitable band edge positions, visible light absorbance, and high chemical stability. To further improve its photocatalytic performance of LaFeO3, the effects of solute concentration in the KCl-flux growth and partial A – and B –site substitution are investigated in this work. Controlling the solute concentration in the range of 1–20 mol% is crucial to grow phase-pure LaFeO3 crystals with idiomorphic shape. With increasing the solute concentration, the flux-based growth route gradually changes to a solid state-based growth route because of a decrease in solubility and an increase in the crystallization core number. The La1− x Sr x Fe1− y Ti y O3 ( x, y = 0, 0; 0, 0.15; 0.15, 0; 0.1125, 0.0375; 0.0375, 0.1125; and 0.075, 0.075) crystals were also synthesized by a KCl-flux method to explore the effect of partial Sr 2+ -to-La 3+ and/or Ti 4+ -to-Fe 2−4+ substitution on photocatalytic performance of LaFeO3 . The Sr 2+ –Ti 4+ co-substitution is found to enhance the photocatalytic performance of LaFeO3 as compared with the corresponding individual substitution (Sr 2+ or Ti 4+ ). The highest photocatalytic hydrogen generation rate (83.2 μmol h −1 ) was observed for Pt-photodeposited La0.925 Sr0.075 Fe0.925 Ti0.075 O3 crystals in 5-h reaction due to the improvement of both bulk properties and photoactivity and the reduction in both grain boundaries and lattice defects stemmed from the Sr 2+ –Ti 4+ co-substitution and KCl flux growth. Graphical abstract: Highlights: Effects of solute concentration and partial A – and B –site substitution are studied. 1–20 mol% solute concentration is essential for flux growth of phase-pure LaFeO3 . Flux-based growth route is gradually dominated by a solid state-based growth route. Sr 2+ –Ti 4+ co-substitution greatly enhanced the photocatalytic activity of LaFeO3 . Bulk properties and photoactivity are enhanced, and grain boundaries and lattice defects are reduced.