Photothermal catalytic CO2 oxidative dehydrogenation of propane 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 utilization of CO₂. To overcome the dual challenges associated with 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 g_cat⁻¹ h⁻¹ at 300 °C, respectively, outperforming previously reported catalysts 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 revealed that propane mainly undergoes dehydrogenation via a direct pathway, while CO₂ is converted into 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 OV 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.