Anti-sintering non-stoichiometric nickel ferrite for highly efficient and thermal-stable thermochemical CO2 splitting

Abstract

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.