G-quadruplex Nanowires To Direct the Efficiency and Selectivity of Electrocatalytic CO₂ Reduction

DNA as a medium for electron transfer has been widely used in photolytic processes but is seldom applied to dark reaction of CO₂ reduction. A G-quadruplex nanowire (tsGQwire) assembled by guanine tetranucleotides was used to host several metal complexes and further to mediate electron transfer processes in the electrochemical reduction of CO₂ catalyzed by these complexes. The tsGQwire modified electrode increased the Faradaic efficiency of cobalt(II) phthalocyanine (Co^IIPc) 2.5-folds for CO production than bare Co^IIPc electrode, with a total current density of 11.5 mA cm⁻². Comparable Faradaic efficiency of HCOOH production was achieved on tsGQwire electrode when the catalytic center was switched to a GQ targeting Ru complex. The high efficiency and selectivity of electrocatalytic CO₂ reduction was attributed to the unique binding of metal complexes on G-quadruplex and electron transfer mediated by GQ nanowire to achieve efficient redox cycling of catalytic centers on the electrode.