CO2 Synergistic Reduction in a Photoanode-Driven Photoelectrochemical Cell with a Pt-Modified TiO2 Nanotube Photoanode and a Pt Reduced Graphene Oxide Electrocathode

摘要

CO2 synergistic reduction in a photoanodedriven photoelectrocatalytic (PEC) cell was conducted with a Pt-modified TiO2 nanotube (Pt-TNT) photoanode and a Ptmodified reduced graphene oxide (Pt-RGO) electrocathode to reduce energy consumption and increase CO2 PEC reduction efficiency. The carbon atom conversion rate of CO2 reduction under PEC conditions was 2.3 times higher than that of the total rate under photocatalytic and electrocatalytic conditions. Synergistic CO2 reduction in the PEC cell was mainly due to the use of the photoanode, which played a dual role during CO2 reduction: (1) anode photovoltage compensated and conferred more negative cathode potential for CO2 reduction and (2) anode water decomposition provided protons and electrons for cathode CO2 reduction. System current density, product generation rate of CO2 reduction, and carbon atom conversion rate increased first and then decreased with increasing deposition amount of Pt on TNT. The optimal photocatalytic activity of the Pt-TNT anode was obtained with a Pt loading amount of 5%, which resulted in the highest system current density of 4 mA/cm~2 and carbon atom conversion rate of 1250 nmol/(h cm~2) under the catalysis of the Pt-RGO cathode.