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

Abstract

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 (CoII Pc) 2.5-folds for CO production than bare CoII Pc 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.