d-Band Center Tuning of Isolated Bimetallic Sites for Synergistic Catalytic Abatement of N2O and NO.

Ammonia combustion unavoidably produces nitrogen oxides (NOx) and nitrous oxide (N2O), which impose severe environmental and climatic concerns. Here we demonstrate that tuning the d-band center of isolated Fe and Co bimetallic sites confined within the channels of BEA zeolite enables the synergistic catalytic abatement of N2O and NO via the N2O-NO-SCR pathway. Electronic coupling between the isolated sites, mediated through the zeolite framework, redistributes charge and shifts the Fe d-band center by ∼0.25 eV toward the Fermi level. This d-band tuning enhances the redox flexibility of Fe while introducing a parallel Co-assisted NO oxidation channel, establishing a dual-site, dual-pathway mechanism, thereby creating favorable synergistic conditions for N2O activation and NO oxidation. As a result, FeCo-BEA achieves nearly complete elimination of both pollutants with remarkable selectivity and long-term stability, with the T90 of N2O lowered by 20 °C and the NO conversion consistently maintained at 100%. This study establishes d-band center regulation of isolated single sites as a powerful design principle for multifunctional zeolite catalysts, offering new opportunities for clean and sustainable NH3-based energy systems.