Lux-Flood Basicity of Mixed La2O3-Alkali Molten Carbonates Determined by Analysis of their Oxygen Solubility Properties

Abstract

Abstract:The Lux-Flood basicity of La 2 O 3 -containing alkali molten carbonate mixtures has been quantitatively estimated by a gas solubility method based on the use of acidic gaseous O 2 for the titration of the oxide concentration in the melt. The amount of gaseous oxygen dissolved in the melt in form of peroxide ion has been taken as a quantitative probe for the carbonate basicity. Results demonstrate that addition of a 0.5 mol % of La 2 O 3 to alkali carbonates is able to dramatically increase the melt basicity and that the degree of this basicity change mostly depends on the melt composition in terms of the average cation size of the alkali carbonate mixture. Plausible dissolution paths of La 2 O 3 in molten carbonates under both acidic and basic regimes are also discussed.

Insight into CO selective chemisorption from syngas mixtures through Li2MnO3; a new H2enrichment material

“…44 Since the lithium precursor for the manganate synthesis was Li 2 O, the presence of the carbonate bands suggests the material reacts with CO 2 from the environment at room temperature, forming the lithium carbonate, in agreement with Lux and Flood acid–base theory. 45 Finally, the broad vibration band centred at 3424 cm −1 is related to the stretching mode ν (OH) of adsorbed hydroxyl species, which are also coming from the humidity of the ambient.…”

Enhanced CO capture properties of Li2MnO3via inducing layered to spinel transition by cation doping with Fe, Co, Ni and Cu

“…Li 2 O (s) + 0.9MnO (s) + 0.1CuO (s) + 0.45O 2(g) → Li 2 (Mn 0.9 Cu 0.1 )O 2.9(s) (5) Li 2 O (s) + 0.9MnO (s) + 0.05Fe 2 O 3(s) + 0.45O 2(g) → Li 2 (Mn 0.9 Fe 0.1 )O 2.95(s) (6) Based on these proposed reactions, each Li 2 MnO 3 solid solution was labeled TM-Li 2 MnO 3 , where TM = Fe, Co, Ni or Cu.…”

“…This kind of ceramic possesses high capture capabilities, in addition to other important physicochemical properties, such as sorptiondesorption kinetics, their capability to operate in high thermal ranges and cyclability. 3,4 Chemically speaking, according to the Lux and Flood acid-base theory, 5 alkaline materials have strong basic characteristics, favoring their interaction with CO and CO 2 , two acid molecules, forming alkaline carbonates. The first work reported in the literature about the carbon dioxide chemisorption process on alkaline ceramics was published by Nakagawa and Ohashi in 1998, using lithium metazirconate (reaction (1)).…”

Oxygen Reduction Reaction at LaNiO3 Supported by Au Ring in Li/Na Eutectic Carbonate with La2O3

“…The ORR mechanisms in molten carbonates have been proposed mainly in three paths that are peroxide mechanism (POP), superoxide mechanism (SOP), and percarbonate mechanism (PCP). (32)(33)(34)(35)(36)(37)(38)(39) Each mechanism of POP, SOP, or PCP was expressed as follows:…”

“…Several reports for the cathodic reaction of MCFC which evaluated the effect of rare-earth oxide addition to molten carbonate (25)(26)(27)(28)(29)(30)(31)(32) were carried out mainly in Li/K or Li/Na/K eutectic carbonate. The catalytic activity of ORR on LaNiO 3 in Li/Na carbonate with La 2 O 3 addition has not been studied.…”