Achieving
Selective and Efficient Electrocatalytic
Activity for CO<sub>2</sub> Reduction Using Immobilized Silver Nanoparticles
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Abstract
Selective
electrochemical reduction of CO<sub>2</sub> is one of
the most sought-after processes because of the potential to convert
a harmful greenhouse gas to a useful chemical. We have discovered
that immobilized Ag nanoparticles supported on carbon exhibit enhanced
Faradaic efficiency and a lower overpotential for selective reduction
of CO<sub>2</sub> to CO. These electrocatalysts were synthesized directly
on the carbon support by a facile one-pot method using a cysteamine
anchoring agent resulting in controlled monodispersed particle sizes.
These synthesized Ag/C electrodes showed improved activities, specifically
decrease of the overpotential by 300 mV at 1 mA/cm<sup>2</sup>, and
4-fold enhanced CO Faradaic efficiency at −0.75 V vs RHE with
the optimal particle size of 5 nm compared to polycrystalline Ag foil.
DFT calculations enlightened that the specific interaction between
Ag nanoparticle and the anchoring agents modified the catalyst surface
to have a selectively higher affinity to the intermediate COOH over
CO, which effectively lowers the overpotential