Hydrophobic surface efficiently boosting Cu2O nanowires photoelectrochemical CO2 reduction activity

The limited mass transfer of CO2 and the competitive hydrogen evolution reaction (HER) during photoelectrochemical (PEC) CO2 reduction usually result in low CO2 reduction activity. Here, we constructed a Cu2O/Sn/PTFE photocathode with a hydrophobic surface based on Cu2O by physical vapor deposition and a dipping method. The CO faradaic efficiency (FE) increased from 34.5% (Cu2O) to 95.1% (Cu2O/Sn/PTFE) at -0.7 V vs. RHE, and the FEH2 decreased from 27.9% (Cu2O) to 3.8% (Cu2O/Sn/PTFE). The introduction of the hydrophobic layer enhances the local CO2 concentration on the electrode surface and effectively isolates H+ from the aqueous electrolyte, thereby enhancing the CO2 reduction activity.

Automated summary

We constructed a Cu2O/Sn/PTFE photocathode with a hydrophobic surface to enhance the CO2 reduction activity in photoelectrochemical (PEC) CO2 reduction. Compared to the Cu2O photocathode, the Cu2O/Sn/PTFE photocathode showed an increase in CO faradaic efficiency from 34.5% to 95.1% at -0.7 V vs. RHE, while the FEH2 decreased from 27.9% to 3.8%. The introduction of the hydrophobic layer enhanced the local CO2 concentration on the electrode surface and effectively isolated H+ ions.