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.
Highlights
The conversion of CO2 to useful fuels as a carbon source has attracted much attention due to its greenhouse effect and fossil shortage [1]
As showed in the Fourier transform infrared spectroscopy (FTIR) spectra of MWNTs pretreated with mixed acid, the introduction of −COOH could be observed from the peak 1732 cm−1 that corresponded to the –C=O stretching frequencies
The cyclic voltammetry (CV) behaviors showed that the Pd-MWNTs catalysts promoted the reduction by lowering the reduction potential and increasing the reduction current
Summary
The conversion of CO2 to useful fuels as a carbon source has attracted much attention due to its greenhouse effect and fossil shortage [1]. Electrochemical reduction can decrease CO2 release and produce a variety of valuable compounds with high current efficiency The products such as formic acid, CO, methane, ethylene, methanol, and ethanol can further be used as feedstock for chemical industry [6,7,8,9]. The electric power can be supplied by solar, wind, and geothermal energy, which are regarded as renewable sources [10]. It can replace a part of fossil fuel consumption, which can further decrease the CO2 emission [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
