Molecular Engineering of Wastewater Nickel into Single‐Site Electrocatalysts for Hydrogen Peroxide Production with Industrial Level Current

Abstract The persistent environmental threat posed by nickel‐laden industrial wastewater demands advanced strategies beyond conventional treatment‐and‐dispose methods. Here, we propose a coordination chemistry‐guided approach to molecularly engineer nickel complexes from wastewater into single‐site electrocatalysts for the two‐electron oxygen reduction reaction (2e − ORR). By precisely tailoring the ligand fields using sodium dimethyl dithiocarbamate (SDD), the derived SDD‐Ni catalyst exhibits >95% Faradaic efficiency for H 2 O 2 synthesis across industrial‐level current densities (200–800 mA cm −2 ) in flow‐cell. Notably, at 781 mA cm −2 , the catalyst delivers a record H 2 O 2 productivity of 70.75 mol g cat −1 h −1 . Real‐wastewater‐derived SDD‐Ni catalysts showed similar performance and sustained >450 h stability in continuous flow‐cell operation, underscoring their practical feasibility. Mechanistic studies reveal that the square‐planar Ni–S 4 coordination structure enables end‐on O 2 adsorption and optimal *OOH intermediates binding, ensuring exceptional 2e − ORR selectivity. This work provides a molecular‐level solution for decentralized H 2 O 2 production by repurposing hazardous Ni wastes into high‐value electrocatalytic systems.