3D-Printed Plate-to-Plate Plasma Reactors for Hydrogen Peroxide Synthesis

Employing 3D printing technology, we fabricated five generations of plate-to-plate plasma reactors for the direct synthesis of hydrogen peroxide (H2O2). This iterative evolution revealed that primary macroscopic bottlenecks (thermal instability and inefficient fluid dynamics) intrinsically trigger secondary issues (electrode oxidation and discharge inhomogeneity). By fundamentally resolving these primary factors through structural and cooling optimizations, we completely suppressed the secondary limitations. The reaction performances of H2/O2 plasma for H2O2 synthesis have been evaluated, and the plasmas have been diagnosed. Based on the reaction performances and diagnostic results, an inverse correlation between H2O2 selectivity and mean electron energy has been established. Consequently, our final Dual-Cooled Reactor promoted uniform, weak discharges, achieving 42.4% selectivity, a space-time yield of 5.6 g/(L·h), and an energy yield of 5.4 g/kWh with excellent 72 h stability. Crucially, this peak performance corresponded to a minimized mean electron energy of 1.11 eV (reduced from >3 eV). This work demonstrates that the synergy between macroscopic structure optimization and microscopic electron energy modulation effectively minimizes product decomposition, providing a design paradigm for efficient plasma synthesis.