Advancing bidirectional hydrogen spillover in heterostructure catalysts for electrocatalytic antimony removal and...

Conventional antimony (Sb) removal from wastewater via adsorption or membrane filtration generates hazardous Sb-contaminated residues, posing significant secondary contamination risks. To overcome these challenges, we introduced an electroreduction strategy using a heterostructured catalyst, Cu nanoparticles on Ti₄O₇ supported by a porous carbon (CuNPs@Ti₄O₇@PC), for the simultaneous Sb(III) reduction and metallic Sb⁰ recovery. This system achieved ≥ 99.9 % Sb(III) removal, reducing residual concentrations to ≤ 5 μg/L across a wide pH range while depositing recoverable Sb⁰ onto the carbon substrate. Integrated experimental and computational studies revealed that the CuNPs@Ti₄O₇ heterostructure optimized the generation and utilization of atomic hydrogen (H*) via bidirectional spillover: alkaline conditions drive reverse H* spillover from Ti₄O₇ interface to the CuNPs sites, while acidic conditions promote H* spillover from CuO sites to the Ti₄O₇ interface, collectively maximizing reactive H* availability for efficient Sb(III) reduction. Further, technoeconomic analysis and life-cycle assessment demonstrated the economic feasibility and environmental benefits compared to the conventional flocculation-sedimentation. By engineering bidirectional H* spillover over metal-support oxide heterostructures, this work advances a sustainable paradigm for simultaneous recalcitrant pollutant removal and resource reclamation from wastewater.