Graphdiyne supported Ag–Cu tandem catalytic scheme for electrocatalytic reduction of CO2 to C2+ products

Abstract

The electrochemical CO₂ reduction reaction (CO₂RR) to added-value C₂₊ products is a worthy way to effectively reduce CO₂ levels in the atmosphere. Cu nanomaterials have been proposed as efficient CO₂RR catalysts for producing C₂₊ products; however, the difficulties in controlling their efficiency and selectivity hinder their applications. Herein, we propose a simple routine to construct a graphdiyne (GDY) supported Ag–Cu nanocluster as a C₂₊ product-selective electrocatalyst and optimize the composition by electrochemical performance screening. The synthesized Ag–Cu nanoclusters are uniformly distributed on the surface of GDY with particle sizes constricted to 3.7 nm due to the strong diyne–Cu interaction. Compared to Cu/GDY, Ag–Cu/GDY tandem schemes exhibited superior CO₂RR to C₂₊ performance with a Faraday efficiency (FE) of up to 55.1% and a current density of 48.6 mA cm⁻² which remain stable for more than 33 hours. Theoretical calculations show that the adsorption energy of CO is much higher on Cu (−1.066 eV) than on Ag (−0.615 eV), thus promoting the drift of *CO from Ag to Cu. Moreover, the calculations indicate that the key C–C coupling reaction of *CO with *COH is more favored on Ag–Cu/GDY than on the original Cu/GDY which contributes to the formation of C₂₊ products. Our findings shed light on a new strategy of combining a GDY support with a tandem catalytic scheme for developing new CO₂RR catalysts with superior selectivity and activity for C₂₊ products.