Electrocatalytic Oxidation Properties Research Articles

Platinum nanoflowers supported on graphene oxide nanosheets: their green synthesis, growth mechanism, and advanced electrocatalytic properties for methanol oxidation

This paper reports a nontoxic, rapid, one-pot and template-free synthesis of three-dimensional (3D) Pt nanoflowers (PtNFs) with high yield and good size monodispersity supported on graphene oxide (GO) nanosheets. The key synthesis strategy employed a low-cost, green solvent, ethanol as the reductant and an advanced, powerful 2D carbon material, GO nanosheets as the stabilizing material. The resulting PtNFs-GO nanosheets were characterized by transmission electron microscopy (TEM), high-resolution TEM, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and electrochemical techniques. It was found that the monodispersed, porous PtNFs supported on GO nanosheets were a uniform size of 30 nm and each was composed of numerous “clean” and small (4 nm) Pt nanoparticles, which revealed an unusually high activity for methanol oxidation reaction compared to commercial Pt black. Furthermore, based on a systematic study of the PtNFs growth conditions, a possible mechanism, and especially the importance of GO in the formation was proposed. Our study demonstrates that GO is a promising support material for developing next-generation advanced Pt based fuel cells and their relevant electrodes in the field of energy.

A novel dinuclear Schiff-base copper(ii) complex modified electrode for ascorbic acid catalytic oxidation and determination

A new dinuclear copper salicylaldehyde-glycine Schiff-base complex [Cu(2)(Sal-Gly)(2)(H(2)O)(2)] was synthesized and structurally characterized. [Cu(2)(Sal-Gly)(2)(H(2)O)(2)] crystallized in the monoclinic system in the P2(1)/c space group. The molecule is a dinuclear complex, formed by two [Cu(Sal-Gly)(H(2)O)] units. The electropolymerization properties of the copper complex on a glass carbon electrode were studied at different potential ranges. The electropolymerization occurred when the high scan potential reached 1.4 V. The modified electrode exhibited good electrocatalytic oxidation properties to ascorbic acid and showed a sensitivity of 22.9 nA μM(-1) (r(2) = 0.9998) and detection limit of 0.39 μM (S/N = 3) in the amperometric determination of ascorbic acid. The designed determination method can be used to analyze vitamin C tablets.

Platinum single crystal electrodes for the electrocatalysis of methane oxidation

The main objective of this paper is to characterize the voltammetric profiles of platinum single crystals of low Miller indexes Pt(100) and Pt(110) and study their catalytic activities on the oxidation of methane. In this way, it was developed a metallic surface modified by presence of other metal oxide, which presents catalytic activity for this reaction. It is well known that the electrooxidation of methane (CH4) leads mainly to the formation of CO2 and H2O, however, the oxidation can also lead to the formation of CO, a reaction intermediate that has strong interaction with metal surfaces, such as platinum. This molecule tends to accumulate on the platinum surface and to passive it, due to the self-poisoning, decreasing its catalytic activity. Therefore, the main aim of this work was the development of a platinum electrode modified by deposition of titanium oxide, which presented electrocatalytic properties for the oxidation of methane.

Gold–platinum yolk–shell structure: a facile galvanic displacement synthesis and highly active electrocatalytic properties for methanol oxidation with super CO-tolerance

In this communication, we prepare a Au-Pt yolk-shell structure through a galvanic displacement strategy and explore its electrocatalytic properties for methanol oxidation. It exhibits high electrocatalytic activity with notable CO-tolerance.

Synthesis and Durability of Highly Dispersed Platinum Nanoparticles Supported on Ordered Mesoporous Carbon and Their Electrocatalytic Properties for Ethanol Oxidation

National Natural Science Foundation of China [20833005, 20873116, 60936003]; State Key Laboratory of Supramolecular Structure and Materials of Jilin University [SKLSSM200910]

Study of zinc hexacyanoferrate—modified platinum electrodes using electrochemical quartz crystal microbalance

In this work, the electrochemical quartz crystal microbalance has been employed to monitor directly the in situ growth of the zinc hexacyanoferrate film during the electrodeposition. Mass changes of the platinum|crystal working electrode were correlated with cyclic voltammetry data. Effects of the sorption of counter-cations (K+, Na+, and $$ {\hbox{NH}}_4^{+} $$ and anions (Cl− and $$ {\hbox{SO}}_4^{2 - } $$ ) during redox reactions were studied. The electrocatalytic oxidation properties of procaine by the zinc hexacyanoferrate films were performed.

ChemInform Abstract: Preparation of Platinum Cluster-Derived Electrodes from Metal Carbonyl Complexes and Their Electrocatalytic Properties for Anodic Oxidation of Methanol.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nickel-borate oxygen-evolving catalyst that functions under benign conditions

Thin catalyst films with electrocatalytic water oxidation properties similar to those of a recently reported Co-based catalyst can be electrodeposited from dilute Ni2+solutions in borate electrolyte at pH 9.2 (Bi). The Ni-Bifilms can be prepared with precise thickness control and operate at modest overpotential providing an alternative to the Co catalyst for applications in solar energy conversion.

Bioinspired catalysis at the crossroads between biology and chemistry: A remarkable example of an electrocatalytic material mimicking hydrogenases

Abstract There is an increasing need for new, efficient and cheap chemical catalysts, as part of the emerging “green” chemistry field. Living organisms provide a wealth of fascinating enzymes, with exceptional catalytic efficiencies and selectivities, which can be either directly exploited in biotechnological synthetic systems or imitated by chemists. The bioinspired catalysis approach exploits the basic chemical principles on which a biological enzyme active site is built in order to generate original functional analogs of this site. This is illustrated here with a molecular electrode material inspired from hydrogenases, metalloenzymes involved in hydrogen metabolism, and displaying exceptional electrocatalytic properties for hydrogen production and oxidation, thus with potential applications for electrolyzer and fuel cell technologies.

A novel route for preparation of PtRuMe (Me = Fe, Co, Ni) and their catalytic performance for methanol electrooxidation

PtRuMe (Me = Fe, Co, Ni) catalysts dispersed on multi-wall carbon nanotubes (MWCNTs) were prepared by ultrasonic-assisted chemical reduction. X-ray diffraction (XRD) showed that Pt existed as face-centered cubic structure, while Ru and Me alloyed with Pt. The calculated particle sizes from XRD data are of 3.40, 3.40, 2.61 and 3.06 nm for PtRu, PtRuFe, PtRuCo and PtRuNi, respectively, and are consistent with TEM results. The electrochemical measurements showed that the addition of Me to PtRu enhances the electrocatalytic properties for methanol oxidation and PtRuNi has the best catalytic activity and stability.

Electrocatalytic Oxidation Properties of Ascorbic Acid at Poly(3,4-ethylenedioxythiophene) Films Studied by Electrochemical-Surface Plasmon Resonance Spectroscopy

In this report, we demonstrate electrocatalytic oxidation properties of ascorbic acid at poly(3, 4-ethylenedioxythiophene) (PEDOT) thin films in view of their potential application for bio-sensing devices. PEDOT thin films were deposited on gold thin films by electropolymerization of EDOT monomer in acetonitrile solvent. In-situ electrochemical-surface plasmon resonance spectroscopy (EC-SPR) was used to detect both electrochemical and optical signals upon an injection of ascorbic acid.

Preparation of SnO 2-CNTs supported Pt catalysts and their electrocatalytic properties for ethanol oxidation

SnO 2-carbon nanotubes (CNTs) composites were prepared by sol–gel method, and characterized by scanning electron microscopy and X-ray diffraction. Due to high stability in diluted acidic solution, SnO 2-CNTs composites were selected as the catalyst support and second catalyst for ethanol electrooxidation. The electrocatalytic properties of the SnO 2-CNTs supported platinum (Pt) catalyst (Pt/SnO 2-CNTs) for ethanol oxidation have been investigated by typical electrochemical methods. Under the same mass loading of Pt, the Pt/SnO 2-CNTs catalyst shows higher electrocatalytic activity and better long-term cycle stability than Pt/SnO 2 catalyst. Additionally, the effect of the mass ratio of CNTs to SnO 2 on the electrocatalytic activity of the electrode for ethanol oxidation was investigated, and the optimum mass ratio of CNTs to SnO 2 in the Pt/SnO 2-CNTs catalyst is 1/6.3.

Preparation of Ru-doped SnO 2-supported Pt catalysts and their electrocatalytic properties for methanol oxidation

Ru-doped SnO 2 nanoparticles were prepared by chemical precipitation and calcinations at 823 K. Due to high stability in diluted acidic solution, Ru-doped SnO 2 nanoparticles were selected as the catalyst support and second catalyst for methanol electrooxidation. The micrograph, elemental composition, and structure of the Ru-doped SnO 2 nanoparticles were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction, respectively. The electrocatalytic properties of the Ru-doped SnO 2-supported Pt catalyst (Pt/Ru-doped SnO 2) for methanol oxidation have been investigated by cyclic voltammetry. Under the same loading mass of Pt, the Pt/Ru-doped SnO 2 catalyst shows better electrocatalytic performance than the Pt/SnO 2 catalyst and the best atomic ratio of Ru to Sn in Ru-doped SnO 2 is 1/75. Additionally, the Pt/Ru-doped SnO 2 catalyst possesses good long-term cycle stability.

Preparation of Ferrocene Nanocrystals by the Ultrasonic‐Solvent‐Substitution Method and Their Electrochemical Properties

Ferrocene nanocrystals are successfully prepared by the ultrasonic-solvent-substitution method. Transmission electron microscopy images show that the average diameter of the nanocrystals is about (40+/-5) nm and X-ray diffraction analysis indicated that the products obtained have a high purity. The optical properties of the products are studied by IR and UV/Vis spectroscopy. UV/Vis spectra indicate that, compared with ferrocene bulk material, the nanospheres show an obvious blue shift. Cyclic voltammetry is used to test the electrocatalytic oxidation properties of the ferrocene nanospheres towards ascorbic acid on the glassy carbon electrode. The results show that the ferrocene-nanosphere-modified glassy carbon electrode exhibits a better electrocatalytic effect than that modified by the ferrocene bulk material in phosphate buffer (pH 5.00). The important factors in the preparation of and a possible mechanism for the formation of ferrocene nanospheres is also discussed. The method could potentially be applied to the preparation of nanomaterials of other organometallic compounds.

Electrocatalytic oxidation of methanol on carbon-nanotubes/graphite electrode modified with platinum and molybdenum oxide nanoparticles

Electrochemical codeposition and electrocatalytic properties of platinum and molybdenum oxide nanoparticles (Pt-MoO x) on carbon-nanotubes/graphite electrode for methanol oxidation were investigated. The micrograph and elemental composition of the resulting Pt-MoO x/CNTs/graphite electrode were characterized by scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS). The results show that the Pt-MoO x particles with the average size of about 50 nm are highly dispersed on the CNTs surface. The Pt-MoO x/CNTs/graphite electrode delivers excellent electrocatalytic properties for methanol oxidation. The highest mass activity( A m) reaches 264.8 A/g at the loading mass of 159.3 μg/cm 2. This may be attributed to the small particle size and high dispersion of Pt-MoO x catalysts deposited on the CNTs surface. The kinetic analysis from electrochemical impedance spectroscopy(EIS) reveals that the existed MoO x phase can improve the chemisorptive and catalytic properties for methanol oxidation.

Hydrothermal Synthesis of Pt-Ru/MWCNTs and its Electrocatalytic Properties for Oxidation of Methanol

Hydrothermal Synthesis of Pt-Ru/MWCNTs and its Electrocatalytic Properties for Oxidation of Methanol

Au@Pt nanoparticles prepared by one-phase protocol and their electrocatalytic properties for methanol oxidation

Au@Pt nanoparticles are prepared in this paper by successive reduction of HAuCl 4 and H 2PtCl 6 precursors. The morphology of Au@Pt nanoparticles is characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and core (Au)-shell (Pt) like structure is observed. The electrocatalytic property of Au@Pt catalyst for methanol oxidation is investigated by cyclic voltammetry (CV) in 1.0M CH 3OH + 0.1 M H 2SO 4 aqueous solution. The effects of atomic ratio of gold to platinum, methanol concentration and CV scan rate on the peak current density of methanol oxidation and long-term cycle stability of Au@Pt catalyst are also studied. The results show that the presence of Au improves the electrocatalytic activity of Pt catalyst for methanol oxidation, and the best atomic ratio of Au to Pt is 1/2.25. Moreover, Au@Pt catalyst shows good long-term cycle stability and 98.6% value of peak current density of methanol oxidation remains after 500 cycles.

Hydrodynamic effects on the performance of an electrochemical reactor for destruction of copper cyanide—Part 1: in situ formation of the electrocatalytic film

An electrochemical reactor with stainless-steel electrodes was used for cyanide destruction and copper electrodeposition from dilute wastewater. With mechanical stirring, pumping or gas sparging, in situ deposition of a Cu oxyhydroxide film occurred on the anode at potentials > 0.7 V vs. AgCl/Ag and had electrocatalytic properties for oxidation of cyanides. The Cu II / Cu I ratio in the electrocatalytic film was found to vary with the hydrodynamic conditions. The minimum mechanical energy dissipation, ranging from 1.5 to 7.2 W m - 3 , necessary to create sufficient turbulence for film formation, was of a similar order of magnitude for all three means of transport enhancement. However, shear rates > 410 s - 1 and shear stresses > 0.41 N m - 2 at the anode resulted in shearing of the film from the stainless-steel support.

Preparation and Properties of Composite Polypyrrole/Pt Catalyst Systems

Three different methods for the preparation and modification of conducting polymer/noble metal catalyst systems consisting of polypyrrole (PPy) and platinum (Pt) are described for the anodic oxidation of methanol. The first method consists of the electrochemical deposition of a thin PPy film on glassy carbon substrate, which is modified with Pt either by electroreduction of hexachloroplatinate, codeposition from a nanodispersed Pt solution, or incorporation of tetrachloroplatinate as counterion followed by cathodic reduction. A second method is based on the preparation of nanoscale PPy(PSS) particles by chemical polymerization with polystyrenesulfonate PSS– as the counterion. This material is a favorable catalyst support for nanodispersed Pt due to its mixed electronic and cationic conductivity. To study the electrochemical properties, the particulate system PPy(PSS)/Pt is fixed in a carbon fiber electrode. A third method was developed which brings the polypyrrole in close contact to a proton exchanger membrane (Nafion) using a special chemical deposition procedure. This method is useful for preparing a membrane electrode assembly (MEA) consisting of Nafion/PPy/Pt. The structural, morphological, and electrocatalytic properties for methanol oxidation were studied depending on the preparation method applied using surface analytical techniques (TEM, SEM, and EDX) and electrochemical measurements (cyclic voltammetry and transient techniques).

Characterization of copper hexabromoplatinate films and their electrocatalytic properties with dopamine, NADH, and S 2O 32−

Copper(II) hexabromoplatinate (CuPtBr 6) films have been prepared by mixing Cu 2+ and PtBr 6 2− ions in an aqueous KBr solution. An electrochemical quartz crystal microbalance (EQCM), a rotating ring-disk electrode, UV–visible absorption spectroscopy and cyclic voltammetry were used to study the deposition and growth mechanism of the copper(II) hexabromoplatinate films. The electrochemical and EQCM properties of the films indicate that a single redox process was confined to the immobilized copper(II) hexabromoplatinate films. The deposition of a copper hexabromoplatinate film occurs when Cu 2+ is reduced to Cu +. In the aqueous KBr solution, Pt IVBr 6 2− is reduced electrochemically to Pt IIBr 6 4−, and the Cu + reacts with the Pt IIBr 6 4− and Pt IVBr 6 2−species. The electrocatalytic oxidation properties of dopamine, NADH, and S 2O 3 2− were determined using the copper(II) hexabromoplatinate films. The electrocatalytic reaction of dopamine with a copper(II) hexabromoplatinate film was investigated using the rotating ring-disk electrode method.