Catalytic Shunt for Sustainable Photosynthesis of Hydrogen Peroxide from Hypersaline Organic Wastewater

Abstract Photosynthetic hydrogen peroxide (H2O2) production from organic wastewater offers a sustainable alternative to the energy-intensive anthraquinone process, yet it is severely hindered by rapid quenching of reactive precursors by concentrated salts in hypersaline organic wastewater. Inspired by biological metabolic shunts, we propose a catalytic shunt strategy that spatially and functionally separates salts and organic contaminants through dynamic modulation of the catalyst electronic structure. Using an unsaturated Cr single-atom model catalyst, chloride ions (Cl–) are preferentially adsorbed onto active sites to enhance electron enrichment, while organic contaminants serve as proton donors. This system achieves a H2O2 production rate of 1.81 mM g–1 h–1, 172.3-fold higher than that of a representative photocatalytic system in pure water, and complete degradation of bisphenol A within 15 min, without external reagents. Mechanistic studies reveal that Cl– adsorption weakens *OOH binding to promote a two-electron oxygen reduction pathway, while contaminant protonation facilitates interfacial proton-coupled electron transfer. Life cycle assessment demonstrates substantially lower environmental burdens across 17 impact categories and a levelized H2O2 cost of $70.6 per ton, well below the commercial price ($140 per ton). This catalytic shunt paradigm transforms waste into a resource, enabling carbon-minimal, decentralized H2O2 production and sustainable remediation of hypersaline organic wastewater.