Transient Pulsed Discharge Preparation of Graphene Aerogel Supported Asymmetric Cu Cluster Catalysts Promote CO2 Reduction to Ethanol

Abstract

Precisely designing asymmetrical structure is an efficient strategy to optimize the performance of metallic catalysts for electrochemical carbon dioxide reduction reactions. Herein, a transient high-density current induced by pulsed discharge is used to rapidly construct graphene aerogel (GAs) supported asymmetric Cu cluster catalysts. Cu atoms decomposed by CuCl2 are converged on graphene surfaces in GAs together with oxygen originating from the intense current and instantaneous high temperature. The atomic and electronic structures of Cu nanoclusters exhibit asymmetric distribution due to lattice distortion and O-doping in Cu crystals. Typically, in CO2 reduction reactions, the selectivity and activity of ethanol are related to the asymmetric structure and strong interfacial interaction of Cu-O/C moieties, exhibiting an ideal Faradaic efficiency (ethanol 75.3% and C2+ products 90.5%) at -1.1 V vs reversible hydrogen electrode (RHE). Meanwhile, the benefit of the strong interaction between Cu nanoclusters and GA supports, the catalyst exhibits long-term stability. In situ XAFS reveals that the Cu4-Cu/C2O1 interaction displays the effective active sites in CO2RR. The pathways of corresponding products and the reaction mechanism on Cu4-Cu/C2O1 moieties are revealed through the in situ attenuated total reflectance Fourier transform infrared spectroscopy and the calculation of density functional theory. This work gives a new solution to solve the challenge for balancing the activity and stability of asymmetric-structure catalysts toward energy conversion reactions.