A novel carbon cycle process assisted by Ni/La2O3 catalyst for enhanced thermochemical CO2 splitting

Thermochemical two-step CO 2 splitting is a potential approach that fixes the sustainable resource into transportable liquid fuels. However, the harsh CO 2 splitting conditions, the limited oxygen release kinetics and capacity of metal oxides block further promoted the CO yield and solar-to-fuel energy efficiency. Here, we propose a different carbon cycle assisted by Ni/La 2 O 3 via coupling methane decomposition with thermochemical CO 2 splitting, replacing conventional metal oxides cycle. Superior performance was demonstrated with methane conversion reached around 94% with almost pure H 2 generation. Encouragingly, CO 2 conversion of 98% and CO yield of 6.9 mmol g −1 derived from CO 2 were achieved, with peak CO evolution rate (402 mL min −1  g −1 ) of orders of magnitude higher than that in metal oxide process and outstanding thermodynamic solar-to-fuel energy efficiency (55.5% vs. 18.5%). This was relevant to the synergistic activation of La 2 O 3 and Ni for CO 2 in carbon cycle, thus improving CO 2 splitting reaction with carbon species.