Anti-Sintering Non-Stoichiometric Nickel Ferrite For Highly Efficient And Thermal-Stable Thermochemical Co2 Splitting

The thermochemical splitting of CO2 into CO based on redox reaction demonstrates great promising for clean energy production. However, the redox material inevitably suffers from high-temperature sintering, leading to an increased ion diffusion barrier that deactivates the bulk phase. In this study, a distinct strategy is demonstrated to neutralize the adverse effect of sintering by engineering a non-stoichiometric nickel ferrite for the CO2 splitting. It maintains a very high CO yield over multiple consecutive cycles, performing better than state-of-the-art redox materials. Extensive characterizations and first principles calculations reveal that the bulk cation diffusion boosts the splitting reaction. Such cation diffusion mode in the non-stoichiometric ferrite provides a more accessible diffusion path for the bulk reaction, leading to accelerated CO2 splitting kinetics. Meanwhile, high stability is demonstrated for the non-stoichiometric nickel ferrite with 100% of the initial reactivity maintaining often 20 redox cycles. Our findings guide to design newly anti-sintering redox materials toward highly efficient energy conversion and production.