Perovskite materials for hydrogen production by thermochemical water splitting. (9th November 2016)

• Record Type: Journal Article
• Authors: Orfila, María; Linares, María; Molina, Raúl; Botas, Juan Ángel; Sanz, Raúl; Marugán, Javier
• Is Part Of: International journal of hydrogen energy. Volume 41:Number 42(2016)
• Page Start: 19329
• Page End: 19338
• Publication Date: 2016-11-09
• Subjects: Perovskites -- Solar hydrogen -- Thermochemical cycles -- Water splitting; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2016.07.041
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The performance of perovskites as redox materials for solar thermochemical hydrogen production and energy storage have been studied theoretically by several authors but there are only a few experimental studies about them. In this work, an evaluation of commercial perovskite materials La1−x Srx MeO3 (Me = Mn, Co and Fe) for thermochemical water splitting is presented. The studied perovskites showed suitable redox properties for energy storage in thermogravimetric analysis (TGA) in presence of air, although only the Co-perovskite material (LSC) exhibited cyclability capacity. Experiments of thermochemical water splitting revealed hydrogen production, with increasing yields for Mn-, Fe- and Co-substituted perovskites, respectively. La/Sr ratio in the range of x = 0.2 to 0.4 showed only a slight influence on the amount of hydrogen produced and on the temperature required for the processes. On the other hand, metal substitution type seems to be a critical factor for the thermal reduction of these perovskites, taking place at temperatures above 1000 °C for the Mn-perovskite, 800 °C for Co-material and 900 °C for Fe-material. These results experimentally demonstrate the suitability of solar hydrogen production based on La1−x Srx MeO3 thermochemical cycles. Moreover, the required temperatures for hydrogen production (230 °C) are lower than those commonly reported in literature for "pure" Men Oy oxide cycles (500 °C), making perovskite-based cycles a promising alternative. The cyclability studies with the LSC showed a slight decrease in the hydrogen production, derived from the segregation of metallic Co during the thermochemical cycle. This study confirmed the LSC perovskite as a promising material for hydrogen production by solar-driven thermochemical water splitting, although a further insight in the optimization of the operation under consecutive cycles is necessary in order to assess the material as alternative as redox material for a full-scale application. Graphical abstract: Highlights: Temperatures for reduction of substituted perovskites established by thermodynamic analysis. Increasing redox capacities in substituted perovskites with Mn > Fe > Co. The Co-perovskite shows the higher hydrogen production by thermal water splitting. The Co-perovskite shows a phase segregation after 4 consecutive cycles in the furnace.