Insights into the catalytic valorization of industrial high-concentration nitrous oxide for propylene synthesis

Abstract

Industrial nitrous oxide (N₂O) emissions at high concentrations pose a significant challenge to climate change, while the oxidative dehydrogenation of propane (ODHP) with N₂O presents a promising strategy for N₂O valorization. However, the activity-selectivity trade-off and rapid deactivation by coke deposition present challenges for future applications. Herein, we select Pd/TiO₂ as a model catalyst and design spatially separated redox centers on the rutile phase catalyst (Pd/R-TiO₂), which enable parallel adsorption and independent activation of C₃H₈ on metallic Pd sites and N₂O on oxygen vacancies. Furthermore, the catalyst suppresses product overoxidation by reducing reactive oxygen species concentration near C₃ intermediates, enhancing C₃H₆ selectivity while inhibiting enolic intermediate and coke formation to ensure catalyst stability. Hydrogen spillover from Pd sites to the TiO₂ surface connects the separated redox reactions, completing the catalytic cycle. This work presents a rational strategy for catalyst design in N₂O-ODHP, contributing to the sustainable mitigation of non-CO₂ greenhouse gases.