Porous Cu1/TiO2–x Catalytic Binding Pocket for Near-Unity Nitrate-to-Ammonia Conversion

Abstract

Electrocatalytic nitrate reduction reaction (NO₃RR) provides unique opportunities to mitigate nitrate wastewater pollution and green ammonia production, yet the sluggish kinetics regarding 8e^– transfer and collective activation of multiple reactants and intermediates remain a fundamental challenge. In this study, we present a cooperative catalyst design of atomically dispersed Cu₁ species embedding onto reduced anatase TiO_2–x with rich multistage pores and oxygen vacancies (POVs), affording the target POVs-Cu^δ+-TiO₂ with a multisite nature. Particularly, the oxygen vacancies and Cu₁ sites in proximity feature a conformational enzyme-mimicking nanopocket, which essentially governs the binding fit of mutative nitrogenate intermediates in the context of synergistic catalysis. The POVs-Cu^δ+-TiO₂ delivers a near-unity Faradaic efficiency (product basis 95.0%) and remarkable ammonia yield rate up to 1321.2 μmol h^–1 mg_cat^–1 at −0.7 V vs RHE. This study underscores the surface topography engineering on reduced metal oxides and the promising synergistic effects over the NO₃RR electrocatalysis, providing a better alternative for nitrate wastewater pollution treatment and ammonia production.