Hydrogen production by thermochemical water splitting with La0.8Al0.2MeO3-δ (Me= Fe, Co, Ni and Cu) perovskites prepared under controlled pH

Compositionally Complex Perovskite Oxides for Solar Thermochemical Water Splitting

“…The XRD patterns for LS_MFC x A before and after the TGA measurements were compared (Figure c,d). A Co-enriched Ruddlesden–Popper (RP) La 2 CoO 4 secondary phase was formed in LS_MFC 0.61 A, LS_MFC 0.79 A, and LSC, consistent with the reported poor phase stability of La 1– x Sr x CoO 3 . ,,, In addition, many other perovskite oxides have been reported to demonstrate phase transformation and even serious decomposition after a thermochemical redox process, including BaCe 0.25 Mn 0.75 O 3 , ,, Gd 0.5 La 0.5 Co 0.5 Fe 0.5 O 3 , La 0.8 Sr 0.2 MeO 3 (Me = Co, Ni, and Cu), La 0.6 Ca 0.4 CoO 3 , Y 0.8 Sr 0.2 Mn 0.6 Al 0.4 O 3 and Y 0.8 Sr 0.2 MnO 3 , LaGa 1– y Co y O 3−δ ( y ≥ 0.1) and La 1– x Sr x Ga 0.5 Co 0.5 O 3−δ ( x = 0–0.5) . In contrast, LS_MFC x A ( x ≤ 0.52) showed no detectable secondary phase in the XRD patterns and displayed rapid and complete reoxidation.…”

“…A Co-enriched Ruddlesden−Popper (RP) La 2 CoO 4 secondary phase was formed in LS_MFC 0.61 A, LS_MFC 0.79 A, and LSC, consistent w i t h t h e r e p o r t e d p o o r p h a s e s t a b i l i t y o f La 1−x Sr x CoO 3 . 26,27,29,30 In addition, many other perovskite oxides have been reported to demonstrate phase transformation and even serious decomposition after a thermochemical redox process, including BaCe 0.25 Mn 0.75 O 3 , 24,30,34 Gd 0.5 La 0.5 Co 0.5 Fe 0.5 O 3 , 25 La 0.8 Sr 0.2 MeO 3 (Me = Co, Ni, and Cu), 28 21 In contrast, LS_MFC x A (x ≤ 0.52) showed no detectable secondary phase in the XRD patterns and displayed rapid and complete reoxidation. Therefore, the phase stability and redox reversibility of LS_MFC x A (x ≤ 0.52) make them suitable for STCH.…”

“…Even though perovskites can have much larger redox capacities (Δδ > 0.15), a longer reaction time (total dwell time for reduction and oxidation steps >2 h) is usually required to reach a fair H 2 production in the reports. − An understanding of the tradeoff between thermodynamic and kinetics properties is needed to optimize the perovskite composition to achieve high H 2 production within a short time (≤1 h). Additionally, many reported perovskite oxides were found to show gradual phase transformation forming secondary phases with reduced or little redox capability in short-term cycles, ,− which is detrimental to H 2 production cycling stability. Therefore, it is desirable to enhance the phase stability of perovskite oxides against thermochemical redox cycles.…”

Hydrogen production, transportation, utilization, and storage: Recent advances towards sustainable energy

“…Thermochemical water splitting (TWS) is a promising and attractive technology for hydrogen production via the splitting of water to form H2 and O2. TWS involves repeated two-step thermochemical reactions involving a series of exothermic and endothermic reactions whereby a metallic oxide is either oxidized or reduced, resulting in the thermal dissociation of water into H2 and O2 [42]. On reduction, the metal oxide reacts with steam and eventually reoxidizes back taking oxygen away from steam and releasing H2 gas in the process [43].…”

Solvent Etching Process for Graphitic Carbon Nitride Photocatalysts Containing Platinum Cocatalyst: Effects of Water Hydrolysis on Photocatalytic Properties and Hydrogen Evolution Behaviors

“…As a renewable energy resource, hydrogen from photocatalytic water-splitting based on semiconductors has the potential to meet the green energy mandate of little or no CO 2 emissions [ 2 , 3 , 4 ]. To date, a variety of semiconductor materials have been employed to simultaneously drive water oxidation and reduction [ 5 , 6 , 7 , 8 , 9 ]. Among a vast number of semiconductor photocatalysts, graphitic carbon nitride (g-C 3 N 4 ), a metal-free organic polymerized material, has been widely utilized in interdisciplinary hydrogen evolution, owing to its excellent photocatalytic characteristics, including low-cost precursors, chemical stability in the ambient environment, sufficient band gap for solar light usage, and ecological friendliness [ 10 , 11 ].…”