Photoelectrocatalytic Reduction of CO2 to CO via Cu2O/C/PTFE Nanowires Photocathodes

The consumption of fossil fuels releases large amounts of carbon dioxide (CO₂) in the atmosphere, causing a serious greenhouse effect. Photoelectrochemical (PEC) reduction of CO₂ to chemical fuels is an effective way to alleviate the current energy and environmental crisis. However, it is still difficult to rationally design efficient PEC CO₂ reduction photocathodes. Cuprous oxide (Cu₂O) is a promising photocathode material, but its surface is susceptible to the accumulation of photogenerated electrons leading to corrosion and activity reduction, and is accompanied by hydrogen evolution reaction (HER), both of which lead to the overall low conversion efficiency of CO₂ reduction by Cu₂O. In this study, the PEC CO₂ conversion efficiency was improved by the synergistic effect of the C electron transport layer to accelerate the electron transfer to alleviate the Cu₂O corrosion problem and the polytetrafluoroethylene (PTFE) hydrophobic layer to inhibit the HER. The test showed that the CO yield of Cu₂O/C/PTFE at the optimum potential (−0.7 V vs. RHE) was 54.6 μmol cm⁻² h⁻¹, which was 3.2 times higher than that of pure Cu₂O. This study provides a facile strategy for constructing an efficient photocathode with great potential for CO₂ reduction.