Anion exchange membrane water electrolyzers (AEMWEs) offer a cost-effective technology for producing green hydrogen. Here, an AEMWE with atmospheric plasma spray non-precious metal electrodes was tested in 0.1 to 1.0 M KOH solution, correlating performance with KOH concentration systematically. The highest cell performance was achieved at 1.0 M KOH (ca. 0.4 A cm À 2 at 1.80 V), which was close to a traditional alkaline electrolysis cell with � 6.0 M KOH. The cell exhibited 0.13 V improvement in the performance in 0.30 M KOH compared with 0.10 M KOH at 0.5 A cm À 2. However, this improvement becomes more limited when further increasing the KOH concentration. Electrochemical impedance and numerical simulation results show that the ohmic resistance from the membrane was the most notable limiting factor to operate in low KOH concentration and the most sensitive to the changes in KOH concentration at 0.5 A cm À 2. It is suggested that the effect of activation loss is more dominant at lower current densities; however, the ohmic loss is the most limiting factor at higher current densities, which is a current range of interest for industrial applications.

Chemical looping technologies are identified as to have a great potential for CO2 capture and fuels synthesis. Oxygen carriers are the fundamental component of a chemical looping process, and the choice of stable and efficient carriers with fast redox kinetics is the key for the successful design of the process. Hence, understanding the reaction kinetics is of paramount importance for the selection of an appropriate oxygen carrier material. This work provides a method for kinetic model selection based on statistical approach to identify the reaction mechanism. The study experimentally investigates the oxidation kinetics of CeO2- by CO2 and applies a statistical method for the selection of the best-fitting kinetic model for the reaction. The kinetic study is performed in the temperature range of 700-1000 o C with CO2 concentration between 20-40% in the feed. The measured peak rates of CO production on ceria were influenced both by temperature and concentration of reactant, showing a marked increase with the temperature and CO2 fraction, from 13.25 ml/min/g at 700 o C and 20% CO2 in feed to 46.08 ml/min/g for 40% CO2 and 1000 o C. The total CO production showed more influence of temperature than CO2 concentration, with a maximum CO yield of 33.66 ml/g at 1000 o C and 40% CO2. The identification of the oxidation kinetic model is performed by fitting different reactions models to the measured reaction rates and statistically comparing them using Residual sum of squares (RSS), Akaike information criterion (AICc) and the F-test for the selection of the best-fitting one. Models corresponding to the nucleation and grain growth reaction mechanism provided a good fit of the data, with the Sestak-Berggren (SB) model showing the best approximation of the measured rate of reaction with evaluated activation energy of 78.5 kJ/mol for the CO2 oxidation.

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