H2 production by the water splitting reaction using photocatalysts derived from calcined ZnAl LDH. (15th March 2019)

• Record Type: Journal Article
• Authors: Suárez-Quezada, M.; Romero-Ortiz, G.; Samaniego-Benítez, J.E.; Suárez, V.; Mantilla, A.
• Is Part Of: Fuel. Volume 240(2019)
• Page Start: 262
• Page End: 269
• Publication Date: 2019-03-15
• Subjects: Hydrogen -- Water splitting -- Calcined LDH -- ZnAl mixed oxides -- Heterojunction -- Photocatalyst; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2018.11.155
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: ZnAl LDH synthesized by coprecipitation was calcined at different temperature. Crystallinity of the material improved as higher calcination temperature. ZnO/Zn6 Al2 O9 heterojunction was observed in the sample calcined at 600 °C. ZnO/ZnAl2 O4 heterojunction was found in the sample calcined at 700 °C. Due to heterojunction effect the highest yield of H2 was reached with LDH 600. Abstract: Photocatalysts based on calcined ZnAl layered double hydroxides were obtained by coprecipitation and the subsequent thermal treatments at different temperatures. The calcined materials were characterized and its photocatalytic behavior was evaluated in the water splitting reaction in presence of UV irradiation. According to the XRD analysis, there was detected the presence of Zn as hexagonal ZnO in all the samples, as well as Al forming ZnAl2 O4 and Zn6 Al2 O9, depending on the temperature of calcination employed. H2 yield was higher as the annealing temperature was increased due to the formation of the heterojunctions of ZnO with the Zn6 Al2 O9 and ZnAl2 O4 oxides, reaching the maximum value in the sample annealed at 600 °C. Some decay in the activity was observed in the sample calcined at 700 °C, probably due to the higher recombination rate of the photogenerated charge carriers in that heterojunction in comparison with that obtained at 600 °C.