Catalytic activity of Pd-Ag nanoparticles supported on carbon nanotubes for the electro-oxidation of ethanol and propanol

Effect of Anode Material on Electrochemical Oxidation of Low Molecular Weight Alcohols-A Review

The growing climate crisis inspires one of the greatest challenges of the 21st century-developing novel power sources. One of the concepts that offer clean, non-fossil electricity production is fuel cells, especially when the role of fuel is played by simple organic molecules, such as low molecular weight alcohols. The greatest drawback of this technology is the lack of electrocatalytic materials that would enhance reaction kinetics and good stability under process conditions. Currently, electrodes for direct alcohol fuel cells (DAFCs) are mainly based on platinum, which not only provides a poor reaction rate but also readily deactivates because of poisoning by reaction products. Because of these disadvantages, many researchers have focused on developing novel electrode materials with electrocatalytic properties towards the oxidation of simple alcohols, such as methanol, ethanol, ethylene glycol or propanol. This paper presents the development of electrode materials and addresses future challenges that still need to be overcome before direct alcohol fuel cells can be commercialized.

Fabrication of Composite Material with Pd Nanoparticles and Graphene on Nickel Foam for Its Excellent Electrocatalytic Performance

Incorporation of precious metallic nanoparticles onto a carbon support material is used to obtain an electrocatalyst for ethanol oxidation. A composite material of spherical palladium nanoparticles (Pd NPs), reduced graphene oxide (rGO), and polydopamine (PDA) on three-dimensional nickel foam (NF) substrate (Pd/rGO/PDA@NF) has been synthesized for ethanol electrocatalysis. The Pd nanoparticles were obtained via reduction of precursor K2PdCl4 using ascorbic acid at 60 °C for 80 min. The rGO with large specific surface area was used in catalysts to provide large amounts of active sites for Pd NPs. Meanwhile, Pd NPs as an effective ingredient in catalyst exhibited excellent electrochemical activity of ethanol oxidation. Local surface plasmon resonance was carried out to determine the optimal concentration of precursor K2PdCl4 aqueous solution, and the absorbance peak of Pd NPs was found at about 340–370 nm by UV-visible spectroscopy. An enhanced property of the composite material Pd/rGO/PDA@NF was demonstrated to catalyze the ethanol oxidation reaction in alkaline electrolyte solution. A higher ratio of forward scan peak current intensity (If) to reverse scan peak current intensity (Ib) was 1.59, which demonstrated the significant anti-poison effect to carbonaceous intermediates of the Pd/rGO/PDA@NF. The value of If can maintain 90.6% after 400 cycles, indicating the higher cycling stability and better electrocatalytic performance toward ethanol oxidation.

A review of recent developments on kinetics parameters for glycerol electrochemical conversion - A by-product of biodiesel

Glycerol is a by-product produced from biodiesel, fatty acid, soap and bioethanol industries. Today, the value of glycerol is decreasing in the global market due to glycerol surplus, which primarily resulted from the speedy expansion of biodiesel producers around the world. Numerous studies have proposed ways of managing and treating glycerol, as well as converting it into value-added compounds. The electrochemical conversion method is preferred for this transformation due to its simplicity and hence, it is discussed in detail. Additionally, the factors that could affect the process mechanisms and products distribution in the electrochemical process, including electrodes materials, pH of electrolyte, applied potential, current density, temperature and additives are also thoroughly explained. Value-added compounds that can be produced from the electrochemical conversion of glycerol include glyceraldehyde, dihydroxyacetone, glycolic acid, glyceric acid, lactic acid, 1,2-propanediol, 1,3-propanediol, tartronic acid and mesoxalic acid. These compounds are found to have broad applications in cosmetics, pharmaceutical, food and polymer industries are also described. This review will be devoted to a comprehensive overview of the current scenario in the glycerol electrochemical conversion, the factors affecting the mechanism pathways, reaction rates, product selectivity and yield. Possible outcomes obtained from the process and their benefits to the industries are discussed. The utilization of solid acid catalysts as additives for future studies is also suggested.

Template synthesis of the Cu2O nanoparticle-doped hollow carbon nanofibres and their application as non-enzymatic glucose biosensors

The cuprous oxide nanoparticle (Cu₂O NP)-doped hollow carbon nanofibres (Cu₂O/HCFs) were directly synthesized by the anodic aluminium oxide (AAO) template. The doped Cu₂O NPs were formed by in situ deposition by direct reduction reaction of precursor carbonization in thermal decomposition and could act as functionalized nanoparticles. The synthesized Cu₂O/HCFs were characterized in detail by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS). The results reveal that Cu₂O/HCFs have a tubular structure with an average diameter of approximately 60 nm. The shape of the Cu₂O/HCFs is straight and Cu₂O NPs are uniformly distributed and highly dispersed in HCFs. Cu₂O/HCFs have good dispersibility. The electrochemical activity of Cu₂O/HCFs was investigated by cyclic voltammetry (CV), the glucose sensors display high electrochemical activity towards the oxidation of glucose. Cu₂O/HCFs can effectively accelerate the transmission of electrons on the electrode surface. Cu₂O/HCFs are applied in the detection of glucose with a detection limit of 0.48 µM, a linear detection range from 7.99 to 33.33 µM and with a high sensitivity of 1218.3 µA cm^-2 mM^-1. Moreover, the experimental results demonstrate that Cu₂O/HCFs have good stability, reproducibility and selectivity. Our results suggest that Cu₂O/HCFs could be a promising candidate for the construction of non-enzymatic sensor.