Electrochemical Reduction of CO₂ to Organic Acids by a Pd‐MWNTs Gas‐Diffusion Electrode in Aqueous Medium

Abstract

Pd-multiwalled carbon nanotubes (Pd-MWNTs) catalysts for the conversion of CO2 to organic acids were prepared by the ethylene glycol reduction and fully characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) technologies. The amorphous Pd particles with an average size of 5.7 nm were highly dispersed on the surface of carbon nanotubes. Functional groups of the MWNTs played a key role in the palladium deposition. The results indicated that Pd-MWNTs could transform CO2 into organic acid with high catalytic activity and CO2 could take part in the reduction reaction directly. Additionally, the electrochemical reduction of CO2 was investigated by a diaphragm electrolysis device, using a Pd-MWNTs gas-diffusion electrode as a cathode and a Ti/RuO2 net as an anode. The main products in present system were formic acid and acetic acid identified by ion chromatograph. The selectivity of the products could be achieved by reaction conditions changing. The optimum faraday efficiencies of formic and acetic acids formed on the Pd-MWNTs gas-diffusion electrode at 4 V electrode voltages under 1 atm CO2 were 34.5% and 52.3%, respectively.

A polymerized ionic liquid functionalized cathode catalyst support for a proton exchange membrane CO2conversion cell

“…24,32 Similar reduction potentials were reported by Lu et al, for Pd-MWNTs system. 33 Moreover, the peak current is signicantly improved upon PIL functionalization due to the accumulation of CO 2 at the conversion site, as we observed in our previous study. 22 It has to be noted that Pt/MWNTs-PIL shows a slight positive shi in reduction peak at À0.6 V, which may be attributed to the local PIL moieties.…”

Carbon-Based Materials for Electrochemical Reduction of CO2 to C2+ Oxygenates: Recent Progress and Remaining Challenges

“…The detected liquid products are HCOOH and CH 3 COOH. The optimal FE of CH 3 COOH production on Pd-MWNTs achieves 52.3% at electrode voltages of 4 V, which is considerably higher than that the FE of HCOOH (34.5%) under the same condition . Du et al prepared a CoO-loaded N-doped carbon material (MC–CNT/Co) by coating CoO nanoparticles on a carbon nanotube and mesoporous carbon hybrid material .…”

Carbon Solving Carbon's Problems: Recent Progress of Nanostructured Carbon‐Based Catalysts for the Electrochemical Reduction of CO2

“…[72][73][74] Recently, CNTs have been used to support nanoparticles of Pd and Cu and have reduced CO 2 to acetic acid and methanol, respectively. [73,74] With an average particle size of 5.7 nm, Pd NPs supported on MWCNTs (Pd-MWCNTs) were able to produce formic and acetic acid with at maximum FE of 34.5% and 52.3%, respectively. However, these maximum efficiencies occurred at relatively high cell potentials (-4 V), did not occur concurrently and were dependent on electrolyte concentration.…”