Electrochemical CO2 Reduction Using Electrons Generated from Photoelectrocatalytic Phenol Oxidation

Electrochemical CO 2 reduction (ECCO 2 R) requires electrons, for example, from oxygen evolution reaction (OER). However, such a multiple-electron-involved reaction is complicated and kinetically slow, leading to high overpotential. Herein, OER is replaced with photoelectrocatalytic phenol oxidation reaction (PECPOR) that provides electrons for ECCO 2 R. In an integrated cell, ECCO 2 R is conducted on the cathode of Cu nanowires and PECPOR is performed on the anode of SnO 2 and Sb coated TiO 2 nanotubes. Significant improvement of ECCO 2 R into CO and hydrocarbons is realized when PECPOR is conducted at a high current density. The use of this integrated system results in the reduction of the specific energy consumption by a factor of 51.33%, compared with the utilization of two half-cells for individual ECCO 2 R and PECPOR. This study thus proposes a novel strategy to couple ECCO 2 R with PECPOR and eventually to tackle the problems of environmental pollution and energy crisis.