Reversed Charge Transfer Enables Dual Active Sites on Ir/hBN for Synergistic N2O Valorization and Propane Selective Oxidation

Valorization of nitrous oxide (N₂O) as a mild oxygen source for light alkanes presents a promising and economical method for mitigating global warming. However, activating N₂O and alkane together often leads to overoxidation and poor selectivity of the products. To disentangle the trade-off between activity and selectivity, herein, an Ir-based hexagonal boron nitride (hBN) catalyst was synthesized to obtain a reversed charge transfer (RCT) from the support to metal centers, forming dual active sites on Ir clusters and the separation of redox centers, as determined via operando near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) and density functional theory (DFT) calculations. Ir/hBN demonstrated a high N₂O conversion (99.5%) and syngas yield (95.9 mol of CO kg_cat^–1 h^–1 and 41.9 mol of H₂ kg_cat^–1 h^–1) during the selective oxidation of propane (C₃H₈) at 450 °C. The electron-rich Ir interfacial perimeter sites (Ir^δ−) enhance N₂O adsorption and N–O bond dissociation to produce active O*; however, facial metallic Ir⁰ sites effectively facilitate C₃H₈ activation, including dehydrogenation and cracking. The separation of H* and O* intermediates, along with the frustrated H*/O* spillover, effectively facilitates the formation of H₂. The *CH₂ intermediate from C₃H₈ breakage migrates and reacts with O* bound to Ir interfacial sites, where it is oxidized to CO₃^2– and subsequently liberates CO. This study provides mechanistic insights into the O element valorization from N₂O with synergetic enhancement in selective oxidation of light alkanes.