3.3 Copper based
Deng et al. synthesized a Cu2O photocathode coated with
a metal-organic framework (MOF) material,
Cu3(BTC)2, which could protect the
underlying Cu2O from undesirable photocorrosion,
facilitate charge separation and electron transfer to active sites, and
provide abundant active sites for catalytic CO2reduction.[97] The obtained
Cu3(BTC)2/Cu2O
photocathode with abundant active sites exhibited a maximum CO
selectivity of up to 95 % and STC efficiency of 0.83 % at −2.07 (V vs.
Fc/Fc+), surpassing those of a bare Cu2O electrode. Zhao
et al. reported a Cu-decorated Co3O nanotube electrode
for PEC CO2 reduction to
formate.[98] Co3O4NTs were first constructed on Co foil by anodization, and Cu
electrodeposition was subsequently performed to synthesize metallic
Cu-loaded Co3O4 nanotube array
electrodes. Because Cu NPs are positively charged due to their
interaction with Co3O4,
CO2 adsorption on Cu NPs occurs in the form of O-Cu,
promoting the protonation of the carbon atom, resulting in the formation
of formate. This synergistic effect between
Co3O4 NTs and metallic Cu NPs results in
remarkable PEC CO2 reduction performance with nearly 100
% selectivity and a maximum production rate of 6.75
mmol·L–1·cm–2 in 8 h PEC process,
which is superior to Co3O4 NTs without
metallic Cu NPs (Figure 4(I) and (J)). Table 2 summarizes the
PEC-CO2RR performance of the co-catalysts.