Photoelectrochemical reduction of CO2 with TiNT

Abstract

In order to reduce CO2 emissions and utilise CO2 as a useful by-product, artificial photosynthesis is being explored for carbon capture and utilisation. Semiconductor photocatalysts excited by solar energy may be used to convert CO2 to fuels or useful chemicals, e.g. CO, CH4, CH3OH. The photocatalytic reduction of CO2 to useful products has been widely studied in order to overcome the greenhouse effect and the current energy necessities. However, this reaction has proved to be extremely low efficiency when compared to other processes. In order to improve these yields, photoelectrochemical reduction of CO2 has been considered, since it combines photocatalysis and electrocatalysis. To this end, a two compartment photoelectrochemical cell (PEC) has been designed and fabricated for the reduction of CO2. This custom built reactor consists of dual phases, where gas phase CO2 is feed into the cathode compartment and an aqueous phase in the anode compartment. The anode and cathodes for a sandwich were the anode perforated foil on exposing aligned titania nanotubes to electrolyte bonded to nafion; which forms a bridge to Pt deposited carbon cloth cathode electrode in gas phase compartment. CO2 reduction products were detected with GC connected to the reactor. The PEC reactor improved the yield and the formal quantum efficiency compared to our previous studies using photocatalytic reactors.