Reactant Enrichment for Aqueous Electrocatalysis

Abstract Electrocatalysis is fundamental to modern energy conversion, driving essential processes like water splitting, CO ₂ reduction, nitrogen fixation, and biomass transformation. These reactions are pivotal for advancing sustainable energy solutions, enabling clean hydrogen production, efficient carbon recycling, and valueadded chemical synthesis. However, most studies currently struggle to achieve the industrially‐relevant current densities (>300 mA cm ⁻² ), alongside challenges in maintaining high product selectivity. Reactant enrichment strategies, which enhance the local concentration of reactants at active sites, have emerged as a powerful solution to these challenges. By optimizing reactant adsorption, these strategies significantly reduce overpotentials while improving current density and selectivity. This review highlights the recent advancements of reactant enrichment strategies in electrooxidation (e.g., OER, electrocatalytic organic oxidation), as well as their application in electroreduction (e.g., CO ₂ /NO ₃ ⁻ reduction, electrocatalytic organic reduction). The integration of multiple enrichment techniques, alongside advanced operando methods, offers a promising path toward achieving industrially relevant efficiencies and selectivity, paving the way for the next generation of sustainable energy conversion technologies.