In this work, four
different 4 cm2-sized nanostructured
Cu-based electrocatalysts have been designed by a one-step electrodeposition
process of Cu metal on a three-dimensional carbonaceous membrane.
One consisted of Cu0, and the other three were obtained
by further simple oxidative treatments. Morphological, structural,
and electrochemical investigations on the four materials were carried
out by scanning electron microscopy, Raman spectroscopy, X-ray diffraction,
linear sweep voltammetry, and potential-controlled electrolysis. All
the electrocatalysts showed promising catalytic activities toward
CO2 electroreduction in liquid phase, with a remarkable
selectivity toward acetic acid achieved when using the oxidized materials.
In particular, the best electrocatalytic activity was observed for
the Cu2O-Cu0 catalyst, working at a relatively
low potential (−0.4 V vs RHE), which exhibited a stable and
low current density of 0.46 mA cm–2 and a productivity
of 308 μmol gcat
–1 h–1. These results were attributed to the nanostructured morphology
that is characterized by many void spaces and by a high surface area,
which should guarantee a large number of CuI and Cu0 catalytic active sites. Moreover, kinetic analyses and preliminary
studies about catalyst regeneration highlighted the stability of the
best-performing catalyst.