Theoretical Insights into a CO Dimerization Mechanism in CO2 Electroreduction.
In this work, we present DFT simulations that demonstrate the ability of Cu to catalyze CO dimerization in CO2 and CO electroreduction. We describe a previously unreported CO dimer configuration that is uniquely stabilized by a charged water layer on both Cu(111) and Cu(100). Without this charged water layer at the metal surface, the formation of the CO dimer is prohibitively endergonic. Our calculations also demonstrate that dimerization should have a lower activation barrier on Cu(100) than Cu(111), which, along with a more exergonic adsorption energy and a corresponding higher coverage of *CO, is consistent with experimental observations that Cu(100) has a high activity for C-C coupling at low overpotentials. We also demonstrate that this effect is present with cations other than H(+), a finding that is consistent with the experimentally observed pH independence of C2 formation on Cu.
†SUNCAT Center for Catalysis and Interface Science Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States.
Joseph H
JH
Montoya
†SUNCAT Center for Catalysis and Interface Science Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States.
Chuan
C
Shi
†SUNCAT Center for Catalysis and Interface Science Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States.
Karen
K
Chan
†SUNCAT Center for Catalysis and Interface Science Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States.|‡SUNCAT Center for Catalysis and Interface Science, SLAC National Accelerator Laboratory, 2675 Sand Hill Road, Menlo Park, California 94025, United States.
Jens K
JK
Nørskov
CO2 electroreduction; density functional theory; electrocatalysis; solar fuels