Tuning C₁/C₂ Selectivity of CO₂ Electrochemical Reduction over in‐Situ Evolved CuO/SnO₂ Heterostructure

Abstract

Heterostructured oxides with versatile active sites, as a class of efficient catalysts for CO2 electrochemical reduction (CO2ER), are prone to undergo structure reconstruction under working conditions, thus bringing challenges to understanding the reaction mechanism and rationally designing catalysts. Herein, we for the first time elucidate the structural reconstruction of CuO/SnO2 under electrochemical potentials and reveal the intrinsic relationship between CO2ER product selectivity and the in‐situ evolved heterostructures. At ‐0.85 VRHE, the CuO/SnO2 evolves to Cu2O/SnO2 with high selectivity to HCOOH (Faradaic efficiency of 54.81%). Mostly interestingly, it is reconstructed to Cu/SnO2‐x at ‐1.05 VRHE with significantly improved Faradaic efficiency to ethanol of 39.8%. In‐situ Raman spectra and density functional theory (DFT) calculations reveal that the synergetic absorption of *COOH and *CHOCO intermediates at the interface of Cu/SnO2‐x favors the formation of *CO and decreases the energy barrier of C‐C coupling, leading to high selectivity to ethanol.

Highly Efficient Electroreduction of CO2 to Ethanol via Asymmetric C–C Coupling by a Metal–Organic Framework with Heterodimetal Dual Sites

“…A plethora of copper-based catalytic sites, including homometallic Cu···Cu dual sites and multi-copper sites, have been devised to enhance the eCO 2 RR performance toward EtOH. − However, in most instances, the FE EtOH falls short of that achieved for another C 2 products, namely ethylene (C 2 H 4 ), , primarily due to the higher energy barrier associated with EtOH product . Specifically, in the eCO 2 RR process, both EtOH and C 2 H 4 products share a common key intermediate, denoted as *CO–*COH (* representing the adsorption site). − It should be emphasized that to yield EtOH, one of the two C–O bonds in the *CO–*COH intermediate must remain intact . However, during the eCO 2 RR process, the intermediate *CO–*COH coordinated to two copper sites, each with one of its C atoms.…”