Growth of silver nanodendrites on titania nanotubes array for photoanode driven photoelectrocatalytic reduction of carbon dioxide

Abstract

Photoanode based CO2 reduction has two major advantages- water oxidation provides required electron-hole pairs and photogenerated anode current compensates the negative cathodic potential required for CO2 reduction. Generally, silver dendrites in combination with copper based substrates have been reported as electrocathodes for electrochemical CO2 reduction. Whereas, in this work, silver nanodendrites decorated titania nanotubes array (Ag-TNT) was used as a photoanode and prepared via simple sodium citrate assisted electrodeposition. Silver dendrites have influenced in light absorption, charge separation efficiency. Ag-TNT employed in photoanode for photoelectrocatalytic reduction of CO2 into CO under the optimized condition with a photocurrent density of 0.29 mA cm−2 at 1.23 V (vs. RHE). This system yielded CO of 61 μmol cm2/h and the design paves the way to facilitate photoelectrocatalytic CO2 reduction through water oxidation.