# Carbon Dioxide Electroreduction on Gold without Metal or Organic Cations

## TL;DR

This study shows that CO2 can be converted into CO on gold surfaces without using metal or organic cations, which could help in developing sustainable carbon conversion methods.

## Contribution

The paper demonstrates CO2 electroreduction on gold without metal or organic cations and proposes a new mechanism for this process.

## Key findings

- CO2 is electrochemically reduced to CO on gold in acidic electrolytes without metal or organic cations.
- H3O+ stabilizes *CO2– formation but requires more negative potentials than alkali metal cations.
- Reduced electric field at the interface increases the overpotential needed for CO2RR.

## Abstract

Extensive research efforts have been concentrated into
the conversion
of CO2 into value-added chemicals as it provides a route
to a circular carbon economy. Electroreduction of CO2 on
Au surfaces allows for the selective transformation of CO2 into CO via carbon dioxide reduction reaction (CO2RR),
and the catalytic activity depends on the concentration and identity
of cations present at the electrode–electrolyte interface.
Experimental reports performed under typical CO2RR-operating
conditions have widely shown that the CO2RR is enabled
by the presence of metal or organic cations in the cathodic interfacial
microenvironment. A remaining question is to address if CO2RR can occur in the absence of metal or organic cations and, if so,
what the mechanism may be. Here, we show that CO2 can be
electrochemically reduced to CO on Au in acidic electrolytes rigorously
controlled to avoid the presence of metal and organic cations and
systematically suggest the important contributions allowing this reaction
to proceed. The formation of CO is confirmed by both qualitative and
quantitative methods using potentiodynamic CO-stripping scans and
chromatography-assisted constant potential electrolysis. Calculations
indicate that H3O+ is able to stabilize the
formation of *CO2
–, albeit at more negative
potentials than when an alkali metal cation is present. Spectroelectrochemical
experiments show that the electric field at the interface is reduced
when metal cations are not added, indicating that the decreased field
stabilization of intermediates could play an important role in increased
overpotential required for the CO2RR to occur.