Photoelectrocatalytic reduction of CO₂ on titania nanotube arrays modified by Pd and RGO

Photoelectrocatalytic reduction of CO₂ was investigated over Pd nanoparticles (NPs) and reduced graphene oxide (RGO) co-modified anodic TiO₂ nanotubes arrays (TNTs) which were grown on a soft Ti wire. Under irradiation, aligned TNTs grown around Ti wire provide orientated pathways for electron transferring to Pd/RGO layers where Pd NPs act as electrons trapping centers and RGO layers function as storage interface with rich electrons for reducing CO₂. It is proposed that the ionization of CO₂ to CO₃^2– in aqueous system is the vital process for the following reduction of CO₂. Moreover, the integrity enables the resulting Pd/RGO/TNTs/Ti wire a superior cathode in an electrochemical cell, improving the efficiency in CO₂ conversion assisted by external potential. The highest yields of methanol and ethanol were 1624 and 536 nmol/cm² h, respectively.