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 comparement 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.

An Overview of Solar-Driven Photoelectrochemical CO2 Conversion to Chemical Fuels

“…In order to reduce the overpotential and overcome the mass-transfer limitation of the traditional H-type PEC CO 2 reduction cell, the gas diffusion electrode (GDE) and PEC CO 2 reduction in gas phase have been widely used. − For example, Kobayashi et al utilized the TiO 2 photoanode and GDE modified by phthalocyanine catalysts containing different metal ions (MPc, where M = Ni, Co, or Sn) for PEC CO 2 reduction . The result suggests that TiO 2 /NiPc-GDE cells show high FE and selectivity (98%) for reducing CO 2 to single product CO, while TiO 2 /SnPc-GDE exhibits high selectivity to HCOOH with FE of 48%.…”

The Future of Carbon Dioxide Chemistry

“…To avoid these drawbacks and increase the efficiency of the process a mixed-phase PEC was proposed, where gas-phase CO 2 is feed into the cathode compartment and an aqueous phase in the anode compartment. [47] Very interesting seems to be the integration of a PV cell with PEC cell, [48] as the photoabsorber in PV cells can continue to utilize the remaining photons that have passed the photoelectrode in PEC cell if the photoelectrode is transparent. This may allow the utilization of incident photons with high efficiency and may offer more energy (given by PV) for the photoelectrodes to reduce CO 2 .…”

Elucidation of the Roles of Ionic Liquid in CO2 Electrochemical Reduction to Value-Added Chemicals and Fuels

“…Carbon capture, storage, and utilization (CCSU) is a pivotal way for reducing emissions in industries. Several CO 2 -utilization technologies using biological and chemical methods such as thermal reduction [3], electrochemical reduction [4], and photoelectrochemical reduction [5] have been investigated. The thermal reduction of CO 2 thermal reduction is far from use in real-world applications because of the high threshold requirements for the temperature, the available materials, and the system configurations [6].…”