Preparation of FTO/CU2O Electrode Protected by PEDOT:PSS and Its Better Performance in the Photoelectrocatalytic Reduction of CO2 to Methanol

Copper(I) oxide (Cu ₂O) was electrochemically deposited on fluorine-doped tin oxide (FTO) glass electrode and covered with a thin layer of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The electrode was studied in the photoelectrocatalytic reduction of CO ₂. Methanol was obtained as the major product with a concentration of 460 μmol L ⁻¹ with a photoconversion yield of 12% after 60 min of reaction under the conditions of UV-Vis (125 W Hg high pressure lamp) and application of 0.0 V vs Ag/AgCl in 3.0 mol L ⁻¹ KCl in buffer sodium carbonate/sodium bicarbonate 0.1 mol L ⁻¹ saturated with CO ₂ gas. The PEDOT:PSS has led to a significant improvement in CO ₂ conversion due to rapid transfer of photogenerated holes. Consequently, the thin layer of PEDOT:PSS also reduces the photooxidation of Cu ₂O to CuO. The Cu ₂O/PEDOT:PSS photocatalytic system was found to have excellent photostability. Similar yield of alcohol was observed after reusing the catalyst six times. [Figure not available: see fulltext.].