Promoting H2O2 Production via Molten-Salt-Engineered Carbon Nitride Photocatalyst in a Triphasic Membrane Reactor

Abstract

Scalable solar production of hydrogen peroxide (H2O2) is hampered by the sluggish diffusion kinetics and poor solubility of O2 in the aqueous solution. Herein, we integrate molten‑salt‑engineered carbon nitride (MS g‑CN) photocatalyst with a hydrophobic PTFE membrane to intensify H2O2 photosynthesis in a 9 cm2 triphasic membrane reactor. By directly feeding O2 to the catalytic sites by percolating through gas diffusional macropores, a remarkable H2O2 production rate of 50 mmol g-1 h-1 with robust stability of at least 20 hours could be achieved in the flow reactor. Computational fluid dynamics calculations reveal the relationship between the position of the triphasic interface and the liquid pressure. This material-reactor co‑design strategy reconciles intrinsic selectivity with mass‑transfer demands, enabling practical H2O2 photosynthesis.