Harnessing Microexplosions for Rapid Pd-N Single-Atom Catalyst Formation

The scalable and energy-efficient synthesis of single-atom catalysts (SACs) is critically challenged by the trade-off between high energy consumption and metal aggregation in conventional thermal activation. Herein, a microexplosive synthesis reactor (MER) is proposed that leverages spatially confined acetylacetonate deflagration within micron-channels (800 µm) to achieve ultrafast atomic dispersion (<20 ms) of palladium. This design decouples metal anchoring thermodynamics from aggregation kinetics by generating localized ultrahigh temperatures (>1500 K, heating rate 10⁵ K s^-1) while maintaining the bulk reactor temperature below 200 °C, thereby suppressing atomic migration and agglomeration. Through synchrotron characterization and multiscale simulations, a three-step mechanism encompassing precursor sublimation-induced spatial confinement, non-equilibrium combustion waves, and N-coordination stabilization is identified. The resulting Pd─N₄ SACs demonstrate exceptional activity and stability (>200 h) in the hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF), outperforming nanoparticle benchmarks by 2-3 orders of magnitude due to optimized electronic structure and maximized active site accessibility. Remarkably, the MER process reduces energy consumption by 98% compared to pyrolysis methods and enables scalable production (kilogram-level) with batch-to-batch consistency. This strategy is universally applicable to 8 metals (e.g., Pd, Pt, Co), establishing a fundamental and practical platform for sustainable SAC manufacturing with minimized carbon footprint.