jp400937e_si_001.pdf (1.57 MB)
Electroreduction of Carbon Dioxide to Methane on Copper, Copper–Silver, and Copper–Gold Catalysts: A DFT Study
journal contribution
posted on 2013-04-25, 00:00 authored by Pussana HirunsitThe
electrochemical reduction of CO2 is a promising
process capable of efficiently recycling CO2 waste and
converting it into hydrocarbon fuel. To date, copper is the best metal
catalyst; however the overpotential to achieve this reaction on Cu
is excessively high. It follows that the development of a catalyst
to efficiently catalyze the conversion with a low overpotential at
a reasonable current density is needed. Many aspects of the molecular
details of the reaction are still unclear. In this work, DFT calculations
are applied to investigate CO2 electroreduction to CH4 over Cu3Ag and Cu3Au stepped surfaces
(211) compared to that over Cu(211). In the resulting analysis, the
Cu3Ag surface shows a slightly lower overpotential and
suppresses OH poisoning compared to the Cu surface, yet the selectivity
toward H2 increases. The Cu3Au is not a good
candidate due to higher overpotential and a relatively weak CO adsorption
resulting in CO desorption rather than further reduction. The CO desorption
can also be problematic on Cu3Ag as well. The thermodynamics
and kinetics of the nonelectrochemical hydrogenations are also examined
to explore alternative paths which
might result in an absence of formaldehyde intermediate production
during CO2 reduction on Cu.