Photothermal catalytic CO2 oxidative propane dehydrogenation over an oxygen-vacancy-rich perovskite-type CeNiO3 catalyst

Abstract

Carbon dioxide oxidative dehydrogenation of propane (CO2-ODHP) offers a promising route for the simultaneous production of propylene and the utilization of CO2. To overcome the dual challenges in activating the stable CO2 molecule and the inert C-H bonds of propane, in the present work, we developed a perovskite-type CeNiO3 catalyst rich in oxygen vacancies (OVs) for photothermally promoted CO2-ODHP. Under optimal conditions, the catalyst delivered propylene and CO production rates of 1229.7 and 876.9 μmol·gcat-1·h-1 at 300 °C, respectively, outperforming previously reported results under comparable photothermal conditions. The abundant OVs in CeNiO3 originate from the cooperative interplay between the Ce3+/Ce4+ redox pair and lattice distortion induced by Ni incorporation. The balanced active lattice oxygen-oxygen vacancy (LO-OV) pairs emerge as a critical factor governing catalytic performance. Combined catalytic evaluations and in-situ DRIFTS studies reveal that propane mainly undergoes dehydrogenation via a direct pathway, while CO2 is converted to CO through the reverse water-gas shift (RWGS) mechanism. This CO2-mediated hydrogen consumption shifts the reaction equilibrium toward propylene and CO formation. Moreover, the synergistic Ce3+/Ce4+ and Ni2+/Ni3+ redox cycles facilitate OVs generation; these vacancies, in turn, activate CO2 to regenerate LOs, which subsequently participate in propane activation. By elucidating the pivotal role of OV modulation in enhancing CO2 activation, this work underscores the importance of bifunctional catalyst design for efficient photothermal CO2-ODHP performance.