Photoelectrocatalytic reduction of CO 2 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 CO32– 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.