| dc.description.abstract | Electrochemical reduction of CO2 using renewable electricity is a promising strategy
to produce fuels and chemical feedstocks while simultaneously decreasing greenhouse
gas emissions. Porous Ag catalysts are reported to have a high CO selectivity and
activity, but the complex combination of porosity and morphology makes it hard
to gain a full understanding of CO2 reduction in porous metals. In order to study
the effect of morphology variations in porous Ag, a template-based electrodeposition
route was developed. In addition, the effect of porosity was established by comparing
porous Ag to non-porous Ag.
Electrodeposition parameters were varied to control the morphology of porous
and non-porous Ag. Porous Ag consistently reached higher CO partial current density
values, 3.45 - 4.25 mA/cm2, compared to non-porous Ag, 2.21 - 2.97 mA/cm2,
at -1.4 V vs RHE. We demonstrated that only for certain Ag morphologies, porous
samples reached higher CO and lower H2 faradaic efficiencies compared to their
non-porous counterpart. In combination with the absence of porosity-induced suppression
of the hydrogen evolution reaction in coral-like porous structures, this indicated
that the morphology surrounding porosity contributes significantly to the
catalytic performance. Therefore, this study establishes that porosity enhances CO2
to CO conversion, while simultaneously highlighting the importance of additional
morphological considerations. | |
