Valorizing N2O Exhaust via Cascade Reforming Enables Efficient Hydrogen Production on Concerted Single-Atom and Nanoparticle 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.