
36 Electrochemically Enabled Sustainability
reduction coupled with a protonation, to yield formic acid (Equation 1.30).
On p-GaP photoelectrochemical electrodes, the same end product, formic
acid, is obtained by the direct reduction of the pyridinium radical–CO
2
complex [149].
As revealed by Figure 1.11, the pyridinium radical can further react with
the previously obtained formic acid (Equation 1.31), and the resulting pyri-
dinium–formyl radical adduct may interact with another pyridinium radi-
cal, yielding one molecule of formaldehyde and two molecules of pyridine
(Equation 1.32). On its turn, formaldehyde may further react with a pyridin-
ium ...