Modeling Thermochemical Solar‐to‐Fuel Conversion: CALPHAD for Thermodynamic Assessment Studies of Perovskites, Exemplified for (La,Sr)MnO₃

Abstract

Two‐step solar thermochemical fuel production has the potential to reduce global greenhouse gas emissions and replace fossil fuels. The success of the technology relies on the development of materials with high thermochemical efficiency. Perovskites with the general structure ABO3 have received much attention recently due to impressive fuel productivity and their amenability of substituting and doping both A‐ and B‐site. Despite the potential of perovskites for solar‐to‐fuel conversion, literature on their solar thermochemical efficiency is scarce and finding the best chemical composition and optimum operation conditions is unknown. For this purpose, this study suggests to use Computer Coupling of Phase Diagrams and Thermochemistry (CALPHAD) data libraries to access the relevant thermodynamic properties of perovskites. This work demonstrates the usefulness of employing CALPHAD data by a full thermodynamic study of the model case compositions of La1–xSrxMnO3–δ. This study uses data on oxygen‐nonstoichiometry and heat capacity in the temperature range of 1073–1873 K relevant for solar‐to‐fuel. Unlike earlier thermodynamic assessments of perovskites that rely on a single literature source and a limited temperature range, the CALPHAD approach takes all available data in literature into consideration. Thermochemical equilibrium models of fuel yields are accompanied by validations toward experimental results in literature, and this study highlights the effects of strontium doping level on the efficiency.

Thermodynamics of paired charge-compensating doped ceria with superior redox performance for solar thermochemical splitting of H2O and CO2

“…This is true not only for the experimental data gathered in this work but also for data extracted from Panlener et al, 37 which indicates the sensitivity of the slope of a constant d line in the Van't Hoff plot when there are few data points for the linear regression. The benecial inuence of a wider temperature range on the extracted thermodynamic properties was also pointed out by Bork et al 49 who uses a database including a wide range of literature data to obtain a higher statistically accuracy.…”

Modifying La0.6Sr0.4MnO3 Perovskites with Cr Incorporation for Fast Isothermal CO2‐Splitting Kinetics in Solar‐Driven Thermochemical Cycles

“…In addition, the oxide should show favorable thermodynamics toward splitting of CO 2 and H 2 O. [10,11] High CO yields were obtained for La 1−x Sr x MnO 3 perovskites (x = 0.4), but the decrease in enthalpy of reduction with increasing Sr content [12] also leads to a lower thermodynamic driving force for fuel production resulting in slower splitting kinetics. Recently, ceria was reported to attain solar-to-fuel efficiencies as high as 5.25%.…”

Experimental Analyses on Feasibility of Chemical‐Looping CoO/CoAl2O4 with Additive for Solar Thermal Fuel Production

“…The second category for solar thermal fuel production is the use of concentrated solar heat to drive endothermic decarbonization reactions directly, which include solar reformation, solar gasification, and solar cracking. The solar reformation is the solar‐heat‐driven steam‐reformation of hydrocarbons, solar gasification refers to the solar‐heat‐driven steam‐gasification of carbonaceous materials, and solar cracking refers to the solar‐heat‐driven decomposition of natural gas and heavy oils, for example . The use of this route to produce solar thermal fuels requires that the concentrating temperature is reduced to 800–1400 °C; therefore, this route is more attractive in the short and medium term .…”

“…The solar reformation is the solar‐heat‐driven steam‐reformation of hydrocarbons, solar gasification refers to the solar‐heat‐driven steam‐gasification of carbonaceous materials, and solar cracking refers to the solar‐heat‐driven decomposition of natural gas and heavy oils, for example . The use of this route to produce solar thermal fuels requires that the concentrating temperature is reduced to 800–1400 °C; therefore, this route is more attractive in the short and medium term . Solar‐driven chemical‐looping combustion (S‐CLC) for solar thermal fuel production is a typical solar reformation candidate, and a schematic for the combination of S‐CLC with power cycles is shown in Scheme …”

“…The use of this route to produce solar thermal fuels requires that the concentrating temperature is reduced to 800–1400 °C; therefore, this route is more attractive in the short and medium term . Solar‐driven chemical‐looping combustion (S‐CLC) for solar thermal fuel production is a typical solar reformation candidate, and a schematic for the combination of S‐CLC with power cycles is shown in Scheme …”