Electrocatalytic Oxidation Of Ethylene Glycol Research Articles

Selective Electrocatalytic Oxidation of Ethylene Glycol into Glycolic Acid at Coin-Group Electrodes: An Investigation on Catalytic Activity and Selectivity

Selective Electrocatalytic Oxidation of Ethylene Glycol into Glycolic Acid at Coin-Group Electrodes: An Investigation on Catalytic Activity and Selectivity

Steering the Selective Production of Glycolic Acid by Electrocatalytic Oxidation of Ethylene Glycol with Nanoengineered PdBi-Based Heterodimers.

Heterodimers of metal nanocrystals (NCs) with tailored elemental distribution have emerged as promising candidates in the field of electrocatalysis, owing to their unique structures featuring heterogeneous interfaces with distinct components. Despite this, the rational synthesis of heterodimer NCs with similar elemental composition remains a formidable challenge, and their impact on electrocatalysis has remained largely elusive. In this study, Pd@Bi-PdBi heterodimer NCs are synthesized through an underpotential deposition (UPD)-directed growth pathway. In this pathway, the UPD of Bi promotes a Volmer-Weber growth mode, allowing for judicious modulation of core-satellite to heterodimer structures through careful control of supersaturation and growth kinetics. Significantly, the heterodimer NCs are employed in the electrocatalytic process of ethylene glycol (EG) with high activity and selectivity. Compared with pristine Pd octahedra and common PdBi alloy NC, the unique heterodimer structure of the Pd@Bi-PdBi heterodimer NCs endows them with the highest electrocatalytic performance of EG and the best selectivity (≈93%) in oxidizing EG to glycolic acid (GA). Taken together, this work not only heralds a new strategy for UPD-directed synthesis of bimetallic NCs, but also provides a new design paradigm for steering the selectivity of electrocatalysts.

Cu2+-regulated one-pot wet-chemical synthesis of uniform PdCu nanostars for electrocatalytic oxidation of ethylene glycol and glycerol

The fabrication of effective and stable electrocatalysts is crucial for practical applications of direct alcohol fuel cells (DAFCs). In this study, bimetallic PdCu nanostars (PdCu NSs) were fabricated by a Cu2+-modulated one-pot wet-chemical method, where cetyltrimethyl ammonium bromide (CTAB) worked as a structure-regulating reagent. The morphology, compositions, crystal structures and formation mechanism of the as-prepared PdCu NSs were investigated by a series of techniques. The unique architectures created abundant active sites, which resulted in a large electrochemical active surface area (9.5 m2 g−1). The PdCu NSs showed negative shifts in the onset potentials and large forward peak current densities by contrast with those of commercial Pd black for the catalytic ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR). It revealed that the PdCu NSs outperformed Pd black in the similar surroundings. This work provides a constructive strategy for fabrication of high-efficiency electrocatalysts for alcohol fuel cells.

Novel electrocatalysts for ethylene glycol oxidation based on functionalized phosphates of bimetals Mn/Ni: Morphology, crystallinity, and electrocatalytic performance

Novel bimetallic phosphates of Mn&Ni were investigated in this study as low-cost phosphate electrodes for ethylene glycol (EG) electrooxidation at high pH (2.0 M NaOH aqueous medium). The investigated electrocatalyst was chemically prepared by two preparation methods: reflux (MnNiPh-Re) and sol-gel (MnNiPh-SG). The as-designed MnNiPh-Re and MnNiPh-SG materials were physiochemically investigated by different techniques to describe the morphology and the impact of the preparation method on its morphology besides crystallinity and chemistry. Interestingly, the preparation method significantly affects the observed morphology. In the case of the sol-gel method, the MnNiPh-SG material has nanocubes characteristics with heterogeneous orientation and exhibits micro sheets in case of reflux strategy made up of super-thin sheets having nanoscale in their thickness and connected to create a different thickness sheet. The electrocatalytic performance of MnNiPh-Re and MnNiPh-SG as working electrodes for EG oxidation was investigated in terms of anodic current density and charge transfer resistance. Interestingly, the anodic current density of the suggested phosphate electrode was increased from 0.018 mA/cm2 to 5.73 mA/cm2 because of only introducing EG to the supporting electrolyte. The fabricated MnNiPh-SG has better EG oxidation if compared with MnNiPh-Re at different EG contents from 0.0 M to 1.0 M Additionally, the improvement of the charge transfer resistances and anodic current density confirms the successful electrocatalytic oxidation of EG over the presented MnNiPh-SG.

Influence of urea on electrocatalytic oxidation of ethylene glycol on porous CuOx/Cu foam anode in alkaline medium

Influence of urea on electrocatalytic oxidation of ethylene glycol on porous CuOx/Cu foam anode in alkaline medium

Oxidative calcination of PdCo with unexpected electrocatalytic performance for ethylene glycol oxidation

Pd-based catalysts have been widely used in alkaline fuel cells. However, up to now, the effects of oxidation treatment of Pd-based catalysts on their application in alkaline fuel cells have been rarely reported. In this paper, PdCo nano-metal catalyst was prepared by calcination-oxidation treatment. It was found that the mass specific activity and area specific activity of the resulting PdO-Co3O4 nano-composite for electrocatalytic oxidation of ethylene glycol in alkaline solution were 3.8 and 2.4 times that of commercial Pt/C, respectively. Compared with PdCo nanometals, the mass specific activity and area specific activity of the PdO-Co3O4 nanocomposite for the electrocatalytic oxidation of ethylene glycol in the alkaline solution increased by 1.6 and 1.2 times, respectively. The experimental and calculated results showed that the surface morphology and active center of the catalyst changed after calcination and oxidation treatment. The adsorption energies of O2 and OH on the Co doped PdO (101) surface decreased, which was beneficial to stabilize the intermediate C2H4OHO*. As a result, the energy barrier for the O−H dissociation on the Co-doped surface was reduced. The strong binding of Co doped PdO (101) with ethylene glycol and its intermediate species led to different electrochemical kinetics and reaction path to produce excellent electric catalytic activity. The synergistic effect of PdO and Co3O4 significantly enhanced the interaction between active oxygen and catalyst surface, which not only facilitates the formation of superoxide species on the catalyst surface, but also improves the redox properties of the catalyst and promotes the electrocatalytic oxidation activity of ethylene glycol. The strategy of bi/multi-metallic oxidation proposed in this paper provides a general methodology for the construction of other catalysts.

Synergistic effects of nanozeolite beta-MWCNTs on the electrocatalytic oxidation of ethylene glycol: Experimental design by response surface methodology

In this work, the electrocatalytic oxidation of ethylene glycol (EG) in the alkaline medium was investigated by the modified carbon paste electrode (CPE) with nanozeolite beta(NZB) and multi-walled carbon nanotubes (MWCNTs) ion-exchanged with Ni(II) cations. The oxidation peak current of EG was increased dramatically at the Ni(OH)2-NZB-MW/CPE surface against Ni(OH)2/CPE, Ni(OH)2-NZB/CPE and Ni(OH)2-MW/CPE. The effects of NZB%, MWCNTs%, NaOH concentration and Ni(II) loading time were considered on the electrochemical response of EG electro-oxidation based on response surface methodology. Results from this method indicated that 10.2% of NZB, 10.2% of MWCNTs in the matrix of fabricated NZB-MW/CPE, 1.6 M NaOH as supporting electrolyte and 16 min loading time of Ni(II) results in the maximum current density. The results indicate that Ni(OH)2-NZB-MW/CPE reveals good electrocatalytic activity toward EG oxidation displaying a suitable stability.

Efficient electro-catalytic oxidation of ethylene glycol using flower-like graphitic carbon nitride/iron oxide/palladium nanocomposite for fuel cell application

The design and development of highly efficient and environmental-friendly methods for the synthesis of electro-catalysts are highly significant for fuel cell applications. Herein, we demonstrate a facile technique for the synthesis of graphitic carbon nitride/iron oxide/palladium nanoparticles (g-C3N4/Fe2O3/PdNPs) composite towards efficient electro-catalytic oxidation of ethylene glycol. g-C3N4/Fe2O3/PdNPs nanocomposite was prepared using a one-step simultaneous electrochemical co-deposition process. The electro-deposition was performed on a single-disk carbon screen-printed electrode (SPE) under acidic electrolyte solution containing g-C3N4 nanosheets, Fe2O3 nanoparticles, and palladium chloride as precursors. The structural and elemental composition of the electrochemically fabricated g-C3N4/Fe2O3/PdNPs nanocomposites modified SPE was investigated using fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy techniques and the results indicated that three-dimensional nanoflower-like Fe2O3 and spherical shaped PdNPs were electro-deposited on the g-C3N4 nanosheets to form the nanocomposite. The voltammetric behavior of the developed g-C3N4/Fe2O3/PdNPs/SPE showed excellent electro-catalytic response towards ethylene glycol and superior electro-oxidation with high durability when compared to commercial Pd/C and other recently reported electro-catalyst materials. Therefore, the proposed g-C3N4/Fe2O3/PdNPs nanocomposite is proved to be an efficient electro-catalyst and can be highly suitable for direct alcohol fuel cell applications.

One-Pot Synthesis of Highly Active Dendritic Platinum-Nickel Nanoalloys for Efficient Electrocatalytic Oxidation of Ethylene Glycol and Glycerol

One-Pot Synthesis of Highly Active Dendritic Platinum-Nickel Nanoalloys for Efficient Electrocatalytic Oxidation of Ethylene Glycol and Glycerol

Particle size effects of PtAg nanoparticles on the catalytic electrooxidation of liquid fuels

The electrocatalytic oxidation of ethylene glycol and glycerol in the presence of PtAg NPs catalyst showed a linear decrease with the increasing particle sizes, providing new clues and hypotheses on how quantum confinement phenomena affect the electrocatalytic performances.

Fabrication of Trimetallic Pt−Pd−Co Porous Nanostructures on Reduced Graphene Oxide by Galvanic Replacement: Application to Electrocatalytic Oxidation of Ethylene Glycol

AbstractIn present work, reduced graphene oxide nanosheets (rGO) decorated with trimetallic three‐dimensional (3D) Pt−Pd−Co porous nanostructures was fabricated on glassy carbon electrode (Pt−Pd−Co/rGO/GCE). First, GO suspension was drop‐casted on the electrode surface, then GO film reduction was carried out by cycling the potential in negative direction to form the rGO film modified GCE (rGO/GCE). Then, electrodeposition of the cobalt nanoparticles (CoNPs) as sacrificial seeds was performed onto the rGO/GCE by using cyclic voltammetry. Afterward, Pt−Pd−Co 3D porous nanostructures fabrication occurs through galvanic replacement (GR) method based on a spontaneous redox process between PtCl2, PdCl2, and CoNPs. The morphology and structure of the Pt−Pd−Co/rGO porous nanostructure film was characterized by scanning electron microscopy, energy dispersive spectroscopy and X‐ray diffraction method. The performance of the prepared electrode was investigated by various electrochemical methods including, cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalytic activity of the as‐prepared modified electrode with high surface areas was evaluated in anodic oxidation of ethylene glycol. The study on electrocatalytic performances revealed that, in comparison to various metal combinations in modified electrodes, trimetallic Pt−Pd−Co/rGO/GCE exhibit a lower onset potential, significantly higher peak current density, high durability and stability for the anodic oxidation of ethylene glycol. The excellent performances are attributed to the rGO as catalysts support and resulting synergistic effects of the trimetallic and appropriate characteristics of the resulted 3D porous nanostructures. Moreover, the influence of various concentrations of ethylene glycol, the potential scan rate and switching potential on the electrode reaction, in addition, long‐term stability have been studied by chronoamperometric and cyclic voltammetric methods.

Shape-controlled electrochemical synthesis of Au nanocrystals in reline: control conditions and electrocatalytic oxidation of ethylene glycol

Gold nanocrystals (NCs) as advanced catalysts towards ethylene glycol (EG) electrooxidation in direct alcohol fuel cells (DAFCs) have some advantages, such as good poisoning-resistance and high electrocatalytic activity. The shape and size control of Au NCs are crucial to their electrocatalytic activity. In this work, the control of morphologies and sizes of prepared Au NCs in reline are systematically investigated by changing electrodeposition conditions: the applied potential, electrodeposition temperature, HAuCl4 concentration and electrodeposition time. Results show that reline (a deep eutectic solvent (DES), a mixture of choline chloride and urea at the molar ratio of 1 : 2) plays an important part in the nucleation and growth of the star-like Au NCs. This approach for preparing star-like Au NCs in reline does not need any supporting electrolyte and organic solvent, and thus is more environmentally friendly than water as a medium. The electrode modified by the as-prepared Au nanostars (NSs) exhibits a good poisoning-resistance ability and electrocatalytic activity for EG electrooxidation in alkaline media. This strategy is a significant way for shape-controlled synthesis of noble metal nanomaterials in DESs that may have potential applications in fields of electrochemical sensors, electrocatalysis and fuel cells.

2,2,6,6-Tetramethyl piperidine-1-oxyl mediated electrocatalytic oxidation of ethylene glycol in water and dichloromethane

2,2,6,6-Tetramethylpiperidinyl-N-oxyl (TEMPO) mediated electrocatalytic oxidation toward ethylene glycol was investigated as a function of electrolyte (aqueous carbonate buffer solution of pH 9.6 and dichloromethane solution with 2,6-lutidine as the base) by cyclic voltammetry and chronoamperometry. Both half-wave potentials and potential separations of electrochemical oxidation of TEMPO in these two electrolytes show differently. Electrocatalytic oxidation of ethylene glycol mediated by TEMPO was firstly reported here, it was observed the onset potential of this electrocatalytic oxidation reaction in dichloromethane solution is larger than that in carbonate buffer solution, moreover, electrocatalytic oxidation rate constant is calculated from chronoamperograms to be 1.63 × 103 L·mol−1·s−1 in carbonate aqueous buffer solution, which is forty times as large as that in dichloromethane solution.

Preparation of NiO nanofibers by electrospinning and their application for electro-catalytic oxidation of ethylene glycol

In this work, nickel oxide nanofibers (NiO-NFs) are produced by electrospinning method and calcination in air for 5 h. The thermal gravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), fourier transform infrared (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and electrochemical impedance spectroscopy (EIS) are used for characterization of the NiO-NFs. The FE-SEM images of the precursor indicate that a large quantity of nanofibers with diameters ranging from 100 to 150 nm with tens of micrometers in length can be acquired. Also, the results show that rough NiO-NFs having large specific surface area are composed of the small nanoparticles. After calcination, the nanofibers are composed of cubic structure. The EIS study shows that the value of charge-transfer resistance of the NiO-NFs modified carbon paste electrode (NiO-NFs/CPE) is much smaller than that CPE, indicating a faster electron-transfer process. The NiO-NFs are used as potential catalysts for electro-catalytic oxidation of ethylene glycol (EG) in 0.2 M NaOH solution. The results demonstrate that the NiO-NFs/CPE reveals good electro-catalytic activity towards EG oxidation, showing a suitable stability and robustness.

Electrocatalytic oxidation of ethylene glycol on palladium coated on 3D reduced graphene oxide aerogel paper in alkali media: Effects of carbon supports and hydrodynamic diffusion

To enhance Pd electro-catalysts in their electro-catalytic activity for C-C bond breaking and tolerance stability, Pd was electrodeposited on high-porosity 3D reduced graphene oxide (rGO) aerogel paper. For comparison, the Pd was also coated on other three different carbon material surfaces: bare carbon fiber paper (CFP), and CFP modified with either 2D graphene oxide (GO) and 2D rGO nanosheets. The Pd/3D rGO aerogel paper exhibits higher catalytic activity toward the electro-oxidation of ethylene glycol in alkaline media and higher excellent tolerance stability than other electrodes due to ultra-high porosity of the 3D rGO support leading to high active electrochemical surface area of the as-fabricated Pd catalyst electrode. In addition, the hydrodynamic diffusion of ethylene glycol to the cayalyst surface investigated in this work plays a major role to the catalytic activity of the as-prepared electrocatalyst. The Pd/3D rGO aerogel rotating disk electrode exhibits a high anodic current density of 267.8mAcm−2 at 3000rpm. This high-performance Pd/3D rGO aerogel may be practically used as the high-efficiency anode of direct ethylene glycol and other related alcohol fuel cells.

Development of ternary hexafluoroisopropylidenedianiline/cyclophosphazene/benzidine- disulfonic acid-carbon nanotubes (HFPA/CP/BZD-CNT) composite as a catalyst support for high performance alcohol fuel cell applications

This work describes the development of a ternary hexafluoroisopropylidene- dianiline/Cyclophosphazene/benzidinedisulfonic acid-carbon nanotubes (HFPA/CP/BZD-CNT) composite as a novel support for the electrooxidation of ethylene glycol. Pt and Pt-Sn nanoparticles were coated on HFPA/CP/BZD-CNT composite through chemical reduction method. The electrocatalysts were characterized by X-ray diffraction, transmission electron microscopy and energy dispersive X-ray analysis. The above results confirm that the Pt and Pt-Sn nanoparticles were uniformly deposited on tri-function groups (-NH, -HSO3 and –CF3 groups) of HFPA/CP/BZD in CNT with an average particle size of ∼2.0nm. The obtained Pt/HFPA/CP/BZD-CNT and Pt-Sn/HFPA/CP/BZD-CNT catalysts were utilized as an anode material for electrocatalytic oxidation of ethylene glycol by using cyclic voltammetry and chronoamperometric analysis in alkaline medium. The ethylene glycol electrooxidation have low onset potential and higher oxidation peak current on Pt/HFPA/CP/BZD-CNT and Pt-Sn/HFPA/CP/BZD-CNT when compared to that of the Pt/CNT and Pt/C catalysts, respectively. Hence, the HFPA/CP/BZD-CNT composite can be used as a potent and promising supporting material for fuel cell applications.

Facile green synthesis of palladium quantum dots@carbon on mixed valence cerium oxide/graphene hybrid nanostructured bifunctional catalyst for electrocatalysis of alcohol and water

Electrocatalytic oxidation of ethylene glycol at Pd quantum dots@C–CeOx/RGO electrode.

PtAg nanotubes for electrooxidation of ethylene glycol and glycerol in alkaline media

We report the electrocatalytic oxidation of ethylene glycol and glycerol in alkaline media over PtAg nanotubes (PtAgNTs), which were prepared through the partial galvanic exchange of Pt on Ag nanowires. The PtAgNTs demonstrated substantially enhanced electrocatalytic performance compared with Pt nanotubes and commercial Pt black and Pt/C catalysts as evidenced by their higher peak current densities, lower onset potentials and better anti-poisoning properties, which originated from the tailored geometric and electronic structures of the PtAgNTs.

PtIr-WO3 nanostructured alloy for electrocatalytic oxidation of ethylene glycol and ethanol.

In this article, we characterized tungsten oxide-decorated carbon-supported PtIr nanoparticles and tested it for the electrooxidation reactions of ethylene glycol and ethanol. Phase and morphological evaluation of the proposed electrocatalytic materials are investigated employing various characterization techniques including X-ray diffraction (XRD) and transmission electron microscopy (TEM). Electrochemical diagnostic measurements such as cyclic voltammetry, chronoamperometry, and linear sweep voltammetry revealed that the tungsten oxide-modified PtIr/Vulcan nanoparticles have higher catalytic activity for ethylene glycol and ethanol electrooxidation than that of PtIr/Vulcan. A significant enhancement for electrooxidation of CO-adsorbate monolayers occurred in the presence of a transition metal oxide relative to that of pure PtIr/Vulcan electrocatalyst. The likely reasons for this are modification on the Pt center electronic structure and/or increasing the population of reactive oxo groups at the PtIr/Vulcan electrocatalytic interface in different potential regions.

High electrocatalysis of ethylene glycol oxidation based on nickel particles electrodeposited into poly (m-toluidine)/Triton X-100 composite

Poly (m-toluidine) (PMT) was formed by successive cyclic voltammetry in a monomer solution containing Triton X-100 (TX-100) at the surface of carbon paste electrode (CPE). Nickel was then incorporated into the polymer by electrodeposition of Ni(II) from NiSO4 acidic solution. The electrochemical behavior of this modified electrode (Ni/PMT(TX-100)/MCPE) was investigated in the electrooxidation of ethylene glycol (EG) using cyclic voltammetry and chronoamperometry techniques. Among the electrodes [Ni/PMT(TX-100)/MCPE, Ni/PMT/MCPE, Ni/MCPE, PMT(TX-100)/MCPE, and CPE] used in this study, Ni/PMT(TX-100)/MCPE showed the most effective catalytic activity. The effects of various parameters such as film thickness, electrodepositing time, TX-100 concentration, MT concentration, and EG concentration were investigated on the electrocatalytic oxidation of EG at the surface of Ni/PMT(TX-100)/MCPE. The catalytic rate constant (k) for EG oxidation was also calculated to be 2.1 × 106 cm3 mol−1 s−1 using a chronoamperometric method.