31Electroreduction of Carbon Dioxide
Subramanian and co-workers [137] performed the two-electron electrore-
duction of CO
2
to formate ions in an electrochemical membrane reactor, in
mildly alkaline KHCO
3
buffer solutions (pH 7.5–8.5). Typically, the carbon-
ate concentration was only 0.5 mol/dm
3
; therefore, in order to avoid signi-
cant ohmic voltage drops through the cell, the conductivity of the electrolyte
was augmented by the addition of K
2
SO
4
. One used a divided lter-press
type electrochemical ow reactor, equipped with a composite peruorinated
cation-exchange membrane (Naon 961 or Naon 430); the reduction of dis-
solved CO
2
was conducted at ambient conditions. This ow reactor enhanced
the mass transfer of CO
2
, as compared to a batc ...