Study on the redox performance of Cu and Ce‐doped CoFe 2 O 4 as oxygen carriers for chemical looping hydrogen generation

In the chemical looping hydrogen generation process, CoFe2O4 is regarded as one of the most excellent candidates for oxygen carriers (OCs). In this paper, the synergistic effect of Cu and Ce added to CoFe2O4 was studied. The doping of Cu and Ce improved the reactivity of CoFe2O4 with methane, and also increased the hydrogen yield and purity. The results indicated that the introduction of Cu and Ce facilitated the deep reduction of CoFe2O4, which was ascribed to the enhanced migration capacity of lattice oxygen. In addition, the addition of Cu inhibited the decomposition of CH4 and alleviated carbon deposition. The Cu4Ce4-CoFe had a suitable Cu/Ce mass ratio, which was more conducive to the formation of excellent synergistic effect to enhance hydrogen production and weaken carbon deposition. The Cu4Ce4-CoFe exhibited outstanding H2 yield (15.42 mmol·g−1) and H2 purity (99.13%). In addition, the reactivity of OC decreased to some extent with the cyclic experiment when the Cu4Ce4-CoFe was used, the H2 yield decreased from ∼15.21 to ∼10.86 mmol·g−1 over 10 experimental cycles. In conclusion, Cu and Ce co-doping is an effective strategy to obtain OCs with preeminent hydrogen production performance and anti-carbon deposition performance.