Electrochemical reduction of carbon dioxide (CO2) is
a promising route to up-convert this industrial byproduct. However,
to perform this reaction with a small-molecule catalyst, the catalyst
must be proximal to an electrode surface. Efforts to immobilize molecular
catalysts on electrodes have been stymied by the need to optimize
the immobilization chemistries on a case-by-case basis. Taking inspiration
from nature, we applied DNA as a molecular-scale “Velcro”
to investigate the tethering of three porphyrin-based catalysts to
electrodes. This tethering strategy improved both the stability of
the catalysts and their Faradaic efficiencies (FEs). DNA-catalyst
conjugates were immobilized on screen-printed carbon and carbon paper
electrodes via DNA hybridization with nearly 100% efficiency. Following
immobilization, a higher catalyst stability at relevant potentials
is observed. Additionally, lower overpotentials are required for the
generation of carbon monoxide (CO). Finally, high FE for CO generation
was observed with the DNA-immobilized catalysts as compared to the
unmodified small-molecule systems, as high as 79.1% FE for CO at −0.95
V vs SHE using a DNA-tethered catalyst. This work demonstrates the
potential of DNA “Velcro” as a powerful strategy for
catalyst immobilization. Here, we demonstrated improved catalytic
characteristics of molecular catalysts for CO2 valorization,
but this strategy is anticipated to be generalizable to any reaction
that proceeds in aqueous solutions.