Copper ferrite and cobalt oxide two-layer coated macroporous SiC substrate for efficient CO-splitting and thermochemical energy conversion.

CO-splitting and thermochemical energy conversion effectiveness are still challenged by the selectivity of metal/metal oxide-based redox materials and associated chemical reaction constraints. This study proposed an interface/substrate engineering approach for improving CO-splitting and thermochemical energy conversion through CuFeO and CoO two-layer coating SiC. The newly prepared material reactive surface area available for gas-solid reactions is characterized by micro-pores CuFeO alloy easing inter-layer oxygen micro mass exchanges across a highly stable SiC-CoO layer. Through a thermogravimetry analysis, oxidation of the thermally activated oxygen carriers exhibited remarkably CO-splitting capacities with a total CO yield of 1919.33 µmol/g at 1300 °C. The further analysis of the material CO-splitting performance at the reactor scale resulted in 919.04 mL (788.94 µmol/g) of CO yield with an instantaneous CO production rate of 22.52 mL/min and chemical energy density of 223.37 kJ/kg at 1000 °C isothermal redox cycles. The reaction kinetic behavior indicated activation energy of 30.65 kJ/mol, which suggested faster CO activation and oxidation kinetic on SiC-CoO-CuFeO O-deficit surfaces. The underlying mechanism for the remarkable thermochemical performances was analyzed by combining experiment and density functional theory (DFT) calculations. The significance of exploiting the synergy between CuFeO and CoO layers and stoichiometric reaction characteristics provided fundamental insights useful for the theoretical modeling and practical application of the solar thermochemical process.