Selective CO₂ Reduction Electrocatalysis Using AgCu Nanoalloys Prepared by a “Host–Guest” Method

Abstract

Multimetallic nanoalloy catalysts have attracted considerable interest for enhancing the efficiency and selectivity of many electrochemically driven chemical processes. However, the preparation of homogeneous bimetallic alloy nanoparticles remains a challenge. Here, we present a room-temperature and scalable, host–guest approach for synthesis of dilute Cu in Ag alloy nanoparticles. In this approach, an ionic silver bromide precursor harboring exogenous Cu cations is reduced to yield ∼20 nm diameter AgCu alloy nanoparticles wherein the % Cu loading can be tuned precisely. AgCu nanoparticles with a 5% nominal loading of Cu exhibit peak activity (−0.23 mA/cm 2 normalized partial current density) and selectivity (83.2% faradaic efficiency) for CO product formation from electrocatalytic reduction of CO 2 at mild overpotentials. These AgCu nanoalloys exhibit a higher mass activity compared to Ag- and Cu-containing nanomaterials used for similar electrocatalytic transformations. Our host–guest synthesis platform holds promise for production of other nanoalloys with relevance in electrocatalysis and optics.