Reduction Of Chloroplatinic Acid Research Articles

Pt catalysts supported on lignin-based carbon dots for methanol electro-oxidation

Pt catalysts supported on lignin-based carbon dots are successfully prepared, and their catalytic performances for methanol electro-oxidation are investigated. Firstly, lignin-based carbon dots (Lg-CDs) are prepared by the acid etching of lignin carbonization products. Then, Pt catalysts supported on lignin-based carbon dots (Pt/Lg-CDs) are synthesized by the reduction of chloroplatinic acid in carbon dots solution. Although Pt/Lg-CDs catalysts aggregate obviously due to the deposition of Pt catalysts on the surface of Lg-CDs, the activity and stability of an optimal Pt/Lg-CDs-800 catalyst are still more outstanding than commercial Pt/C (40%Pt) and PtRu/C (30%Pt+15%Ru) catalysts for methanol electro-oxidation reaction (MOR) in acidic solutions. A large number of oxygen-containing groups on the surface of Lg-CDs-800 facilitate the uniform and stable deposition of Pt catalysts, and make the surface of more Pt catalysts expose to reaction system, thereby improving catalytic performance.

Platinum loaded cyclomatrix polyphosphazene submicrospheres improve fire retardancy of epoxy with very low addition

Abstract Platinum nanoparticle loaded polyphosphaziene submicrosphere (Pt-PPS) was synthesized via the reduction of chloroplatinic acid on the surface of PPS microspheres . Pt nanoparticles were dispersed uniformly with an average particle size of 2 nm from the SEM and TEM investigation. The cone calorimeter tests showed that a very low Pt incorporation (0.15%) can significantly improve the flame retardancy of epoxy resin (EP). The heat release rate (HRR) and total heat release (THR) were reduced by 40.2% and 23.2%, respectively. The improvement in flame retardancy is contributed by the catalytic carbonization effect of Pt synergizing with PPS submicrospheres.

Ultrasensitive colorimetric determination of silver(I) based on the peroxidase mimicking activity of a hybrid material composed of graphitic carbon nitride and platinum nanoparticles.

A hybrid material composed of graphitic carbon nitride (g-C3N4) and platinum nanoparticles (PtNPs) with peroxidase mimicking activity was used to design a rapid, sensitive and low-cost colorimetric method for the determination of Ag(I). The g-C3N4-PtNPs hybrid was synthesized by reduction of chloroplatinic acid using sodium borohydride under ultrasonication and in the presence of g-C3N4. The hybrid can catalyze the oxidation 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue-colored product with an absorption maximum at 652nm. On addition of Ag(I) and in the presence of citric acid, it will be reduced to form Ag(0) under the catalytic action of PtNPs. Ag(0) is then adsorbed on the surface of the g-C3N4-PtNPs. This results in the inhibition of the enzyme mimetic activity of the hybrid. Hence, less blue product will be formed from TMB. Under optimum conditions, Ag(I) can be quantified in the 0.05-5.0nM concentration range with a 22 pM detection limit. This assay is rapid and reliable and was applied to the determination of Ag(I) in spiked real water samples. Graphical abstract A hybrid nanomaterial consisting of graphitic carbon nitride and platinum nanoparticles (g-C3N4-PtNPs) can catalyze the oxidation of tetramethylbenzidine (TMB) to produce a blue-colored product (TMBox). The enzyme mimetic activity of the hybrid is inhibited by Ag+, thereby decreasing the generation of blue product from TMB.

Preparation of highly dispersed CuPt nanoparticles on ionic-liquid-assisted graphene sheets for direct methanol fuel cell

In this work, CuPt nanocomposites were decorated on ionic-liquid-assisted graphene and their electrocatalytic activities for methanol oxidation were investigated. The procedure involved the synthesis of graphene by electro-oxidation of pure graphite in an ionic-liquid/water solution, followed by the deposition of Cu nanoparticles on graphene and their further reduction of chloroplatinic acid. The catalysts were characterized by using transmission electron microscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, Raman spectroscopy and X-ray diffraction. Subsequently, electrocatalytic activities of this catalyst for methanol oxidation were measured by cyclic voltammetry, chronoamperometry and CO-stripping voltammetry. Results showed that the electrocatalytic activity and stability of CuPt/ionic-liquid-assisted graphene for methanol oxidation was better than that on commercial carbon blacks, which was attributed to the increase of the graphene conductivity by ionic liquid and the facile removal of intermediate poisoning species with the aid of Cu, demonstrating that ionic-liquid-assisted graphene can be an alternative support for Pt immobilization in direct methanol fuel cells.

Electro-catalytic performance of Pt-supported poly (o-phenylenediamine) microrods for methanol oxidation reaction

Poly (o-phenylenediamine) (PoPD) microrods were obtained by interfacial polymerization using ferric chloride as oxidant and without any template or functional dopant. Pt/PoPD nanocatalysts were prepared by the reduction of chloroplatinic acid with sodium borohydride, and the composite catalysts formed were characterized by X-ray diffraction and electrochemical methods. The nanocomposite of Pt/PoPD microrods has been explored for their electro-catalytic performance towards oxidation of methanol. The electro-catalytic activity of Pt/PoPD was found to be much higher (current density 1.96 mA/cm2 at 0.70 V) in comparison to Pt/Vulcan electrodes (the current density values of 1.56 mA/cm2 at 0.71 V) which may be attributed to the microrod morphology of PoPD that facilitate the effective dispersion of Pt particles and easier access of methanol towards the catalytic sites.

Photocatalytic Properties of Pt/GaP Nanoparticles under Visible Light Irradiation

Gallium phosphide(GaP) nanoparticle was synthesized by the reaction of sodium phosphide and gallium chloride in dimethylbenzene.GaP-supported platinum photocatalysts,Pt(0.80wt%)/GaP and Pt(4.2wt%)/ GaP nanoparticles,were prepared by the simple reduction of chloroplatinic acid(H2PtCl6) with hydrazine hydrate(N2H4.H2O).The photocatalytic activities of GaP and Pt/GaP nanoparticles for the decomposition of crystal violet were investigated under visible light irradiation.The results indicate that GaP,Pt(0.80wt%)/GaP and Pt(4.2wt%)/GaP nanoparticles can harness visible light to decompose crystal violet in aqueous solution.The photocatalytic activity of Pt(0.80wt%)/GaP is better than that of GaP while the photocatalytic activity of GaP is better than that of Pt(4.2wt%)/GaP.The Pt coverage has an important effect on the photocatalytic activity of Pt/GaP nanoparticles.

Synthesis, characterization and electrocatalytic activity of Pt supported on poly (3,4-ethylenedioxythiophene)–V 2O 5 nanocomposites electrodes for methanol oxidation

Platinum nanoparticles have been supported on PEDOT–V 2O 5 nanocomposite through the reduction of chloroplatinic acid with formic acid. PEDOT–V 2O 5 hybrid nanocomposites are thus found to be a good support of Pt particles as catalysts for oxidation of methanol. Surface properties and morphology of the Pt deposit on nanocomposite were characterized using XRD, SEM, EDAX and TEM analysis. EDX mapping and TEM images show the fine dispersion of Pt nanoparticle on the nanocomposite support. TEM images show 4-nm Pt nanoparticles dispersed on the nanocomposite surfaces. The electrocatalytic activity of Pt/PEDOT–V 2O 5 nanocomposite catalysts toward methanol oxidation was investigated and compared with Pt/C. Pt/PEDOT–V 2O 5 nanocomposite catalysts exhibited enhanced electrocatalytic activity when compared with commercially available Pt/C catalysts and the chronoamperometric response revealed better activity and stability of the nanocomposite electrode when compared with the Pt/C electrode.

Synthesis and application in surface-enhanced Raman scattering property of fist-like platinum microparticles

Platinum microparticles with fist-like shape were synthesized through the reduction of chloroplatinic acid (H 2PtCl 6) with absolute ethanol under hydrothermal atmosphere, whose diameters and lengths can be effectively controlled by varying H 2PtCl 6 concentration. Unlike previous methods for only synthesizing platinum nanoparticles of about 10 nm or even smaller, the use of the hydrothermal and surfactant-free system provides a shortcut strategy to prepare micron-sized platinum particles. Surface-enhanced Raman scattering (SERS) investigation demonstrated that the microfists have SERS activity and similar SERS enhancement to an electrochemically roughened Pt electrode. We believe that the Pt microfists should be not only an ideal model to understand and calculate the SERS enhancement mechanism of electrochemically roughened transitional metal but also may find practical applications for electronics, photonics, and microdevices.

Electrochemical oxidation of methanol on Pt/V2O5–C composite catalysts

Platinum nanoparticles have been supported on V2O5–C composite through the reduction of chloroplatinic acid with formaldehyde. The catalyst was characterized by X-ray diffraction and transmission electron microscopy. Catalytic activity and stability for the oxidation of methanol were studied by using cyclic voltammetry and chronoamperometry. Pt/V2O5–C composite anode catalyst on glassy carbon electrode show higher electro-catalytic activity for the oxidation of methanol. High electro-catalytic activities and good stabilities could be attributed to the synergistic effect between Pt and V2O5, avoiding the electrodes being poisoned.

One-step synthesis of carbon-onion-supported platinum nanoparticles by arc discharge in an aqueous solution

Carbon-onion-supported platinum nanoparticles were synthesized using a simplified arc-discharge-in-solution method. Pt nanoparticles with diameters of 5nm were found to form during reduction of chloroplatinic acid and were simultaneously supported on carbon onions formed in the arc discharge process. X-ray powder diffraction, scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy were used to study the structural and morphological properties of the samples. The formation mechanism of the Pt/carbon onion hybrids was briefly discussed.

Preparation and the physical/electrochemical properties of a Pt/C nanocatalyst stabilized by citric acid for polymer electrolyte fuel cells

Pt/C nanocatalysts were prepared by the reduction of chloroplatinic acid with sodium borohydride, with citric acid as a stabilizing agent in ammonium hydroxide solution. These nanocatalysts were obtained by altering the molar ratio of citric acid to chloroplatinic acid (CA/Pt) from 1:1, 2:1, 3:1 to 4:1. Transmission electron microscopy and X-ray diffraction analyses indicated that the well-dispersed Pt nanoparticles of around 3.82 nm in size were obtained when the CA/Pt ratio was maintained at 2:1. X-ray photoelectron spectroscopy measurements revealed that the 2:1, 3:1 and 4:1 molar ratio catalysts had a relatively higher amount of Pt in their metallic state than did the 1:1 molar ratio catalyst. Cyclic voltammetry results demonstrated that the Pt/C nanocatalysts annealed at 400 °C in an N 2 atm provided higher electrocatalytic activity. Among all the molar ratio catalysts, the 2:1 molar ratio catalyst exhibited the largest electrochemical active surface (EAS) area, and its methanol oxidation reaction current was superior to the E-TEK catalyst. The oxygen reduction reaction of the catalysts studied by linear sweep voltammetry and tested in a fuel cell indicated that the catalytic activity of the 2:1 molar ratio catalyst was comparable to that of an E-TEK catalyst.

Synthesis and Characterization of Surfactant-Stabilized Pt/C Nanocatalysts for Fuel Cell Applications

Platinum nanocatalysts supported on Vulcan XC-72 carbon have been synthesized through the reduction of chloroplatinic acid with formic acid, using surfactant tetraoctylammonium bromide (TOAB) as the stabilizer in the solvent tetrahydrofuran (THF). These nanocatalysts are synthesized by changing the molar ratio of TOAB to chloroplatinic acid, i.e., N/Pt ratio of 0.76, 0.38, and 0.19. A control catalyst that does not contain TOAB is also synthesized by this method for comparison purposes. Comparison of the morphological properties of these catalysts by transmission electron microscopy (TEM) reveals that the N/Pt ratio of 0.76 catalyst has well-separated smaller particles (2.2 nm) than the other lower molar ratio and control catalysts. X-ray diffraction (XRD) analysis indicates the presence of platinum in the fcc phase and the average size of the particles calculated from the XRD peak widths agreed well with the TEM results. X-ray photoelectron spectroscopic (XPS) measurement of the 0.76 ratio catalyst reveals that a higher amount of Pt exists in its metallic state (73.64% of Pt(O) and 26.36% Pt(II)) and the data are on par with that of the E-TEK catalyst. Stabilization effect of the TOAB on the surface of platinum particles has been discussed with respect to the different N/Pt molar ratios. The XPS technique has been exploited to prove the presence of coverage of TOAB and its subsequent removal from the surface of the Pt particles, which is considered to be the crucial step prior to the electrochemical measurements. Electrochemical measurements have demonstrated that the surface area of the 0.76 ratio catalyst is higher than that of the lower molar ratios (0.38 and 0.19).

Synthesis of Thiolate-Stabilized Platinum Nanoparticles in Protolytic Solvents as Isolable Colloids

Water-dispersible, isolable thiolate-stabilized platinum nanoparticles are synthesized by two one-phase methods: one is conducted in water; another mainly in methanol, through the reduction of chloroplatinic acid with sodium borohydride, using mercaptosuccinic acid (MSA) as the stabilizer. The well-separated particles with mean diameter of 2.5 nm are obtained in water when the initial molar ratio of MSA to chloroplatinic acid (S/Pt) is 0.7. High-resolution transmission electron microscopy reveals that most particles are fcc single crystals of cuboctahedral or truncated octahedral morphology with cell parameter similar to that of bulk Pt. The average particle diameter increases from 2.5 nm to around 4.7 nm upon decreasing the S/Pt ratio from 0.7 to 0.1; at the same time, particle aggregation occurs due to the incomplete coverage of thiolate molecules on the particle surface. The particles with mean diameter of 2.3 nm are also obtained while using methanol as the solvent at an initial S/Pt ratio of 0.5. Ex...

ChemInform Abstract: Platinum Dispersed on Carbon Catalyst for a Fuel Cell: A Preparation with Sorbitan Monolaurate.

AbstractThe preparation of Pt/carbon catalysts by reduction of chloroplatinic acid with MeOH containing sorbitan monolaurate is found to yield highly dispersed Pt particles.

Platinum Dispersed on Carbon Catalyst for a Fuel Cell: A Preparation with Sorbitan Monolaurate

Platinum was highly dispersed on acetylene black by the reduction of chloroplatinic acid with methyl alcohol containing sorbitan monolaurate. When the preparation concentration of sorbitan monolaurate was 5.0 g/liter and the heat‐treatment temperature to decompose the residual sorbitan monolaurate in the catalyst was 500°C, the electrode fabricated with this catalyst showed the highest performance for oxygen reduction in phosphoric acid at 190°C. The residual surface‐active agent was carbonized on heat‐treatment and the pore distribution of the catalyst was changed. The time dependence of the change in platinum particle diameter was measured at 0.80V vs. RHE in phosphoric acid at 205°C. The particle diameter hardly changed during a period of about 400h.

Preparation of a platinum catalyst on charcoal by reduction of chloroplatinic acid with hydrogen

Preparation of a platinum catalyst on charcoal by reduction of chloroplatinic acid with hydrogen