Au Nanocrystals Modified Holey PtTeAu Metallene Heteronanostructures for Plasmon‐Enhanced Nitrate Electroreduction

Abstract Ammonia (NH₃) is an essential chemical for agricultural production and a promising next‐generation hydrogen‐rich fuel. The electrocatalytic nitrate (NO₃⁻) reduction reaction (NO₃RR) to NH₃ provides a sustainable and low‐energy method to replace industrial NH₃ synthesis. However, the NO₃⁻ to NH₃ conversion is limited by the complex eight‐electron and nine‐proton reduction processes, thus it is highly desirable to develop efficient electrocatalytic materials to overcome the kinetic barrier of NO₃RR. Herein, Au nanocrystals (Au‐NCs) modified holey PtTeAu metallene (PtTeAu‐ML) heteronanostructures (Au‐NCs/PtTeAu‐MLs) are designed through phase and interface engineering, which achieve the high NH₃ yield (3.499 mg h⁻¹ mg_cat⁻¹) and Faradaic efficiency of 96.3% for NO₃RR at −0.03 V versus RHE. Detailed investigations reveal that the introduction of Te atoms significantly inhibits the high activity of Pt atoms for hydrogen evolution reaction that competes with NO₃RR. Density functional theory results demonstrate that Au atoms further modulate the electronic structure of Pt in PtTe‐MLs, resulting in the upward shifted d band center of Pt and in turn the optimized NO₃RR process on PtTeAu‐MLs. Furthermore, Au‐NCs allows the sustainable sunlight energy to accelerate the NO₃RR kinetics at PtTeAu‐MLs because of the localized surface plasmon resonance of Au, inducing a higher NH₃ yield of 4.684 mg h⁻¹ mg_cat⁻¹ under light irradiation condition.