Enhanced oxygen migration in tailored lanthanum-based perovskite for solar-driven dry reforming of methane

CO 2 and methane are the first and second most important greenhouse gases (GHGs). Solar thermal chemical looping dry reforming of methane (STCL-DRM) is a promising route to reduce methane/CO 2 emissions and achieve solar-to-chemical production. However, the lack of suitable oxygen carrier (OC) catalysts impedes the development. In this study, the tailored lanthanum-based perovskite by Cu and Ni substitution was synthesized as the OC catalyst. In the partial oxidation of methane, the tailored perovskite LaCu 0.5 Ni 0.5 O 3 can be reduced at the temperature of 450 °C–750 °C, and later the consumed lattice oxygen was supplemented through CO 2 reduction. Based on the DFT calculations, LaCu 0.5 Ni 0.5 O 3 exhibited a lower oxygen vacancy formation energy of 0.78 eV and a lower energy barrier of 0.32 eV for the oxygen migration from the second to the first layer. Compared to the undoped lanthanum-nickel perovskite and ceria, LaCu 0.5 Ni 0.5 O 3 shows superior oxygen migration ability. The enhanced oxygen migration and synergistic effect of Cu and Ni substitution were identified and unveiled through thermodynamic and computational study. The fixed-bed reactor tests yielded outstanding results with methane conversion >83 %, CO selectivity >97 %, and near-complete CO 2 conversion at 650 °C. Furthermore, we evaluated two pathways, STCL-DRM using LaCu 0.5 Ni 0.5 O 3 and traditional steam methane reforming (SMR), for methanol/acetic acid production. The proposed STCL-DRM process using LaCu 0.5 Ni 0.5 O 3 demonstrated ∼86 % reduction in energy demand compared to SMR while enabling negative CO 2 production. This process showed a carbon efficiency of roughly 81.9 %, which was 5 % higher than traditional SMR. These results show that the STCL-DRM can provide a competitive route for realizing solar thermochemical CO 2 reduction, clean conversion of methane, and efficient solar-to-chemical production.