ValorizingN2O Exhaust via Cascade ReformingEnables Efficient Hydrogen Production on Concerted Single-Atom andNanoparticle Ru Sites

Valorization of nitrous oxide (N2O), a potent greenhouse gas, through cooperative reforming with light alkanes offers a promising route toward carbon-negative hydrogen production. Here, we report a Ru1+n/ZnO catalyst that integrates isolated ruthenium single atoms (Ru1) with subnanometre ruthenium nanoparticles (Run), enabling cascade N2O valorization coupled with propane dry reforming. The catalyst reduces noble-metal cost by ∼70% compared with Ir-based benchmarks while delivering markedly enhanced hydrogen production (145.1 mol H2 kgcat–1 h–1) together with stable operation for at least 72 h. Mechanistic studies reveal that densely anchored Ru1 sites in close proximity to Run electronically modulate the nanoparticles toward a more metallic state, promoting hydrocarbon activation. Meanwhile, CHx* intermediates formed on Run are rapidly consumed through reforming with O* species generated on satellite Ru1 via N2O activation, enabling an efficient cascade reaction pathway that suppresses side reactions and enhances hydrogen generation. This work demonstrates a cooperative single-atom–nanoparticle catalytic strategy for greenhouse-gas valorization and efficient hydrogen production, providing insights into the rational design of multifunctional reforming catalysts.