A sonochemical process was developed to treat carbon nanotubes in nitric and sulfuric acids create surface functional groups for metal nanoparticle deposition. Carbon treated the are shown lead deposition of uniformly dispersed high loading Pt nanoparticles, which have not been achieved with reflux processes. nanoparticles a size less than 5 nm up 30 wt % little aggregation were synthesized on sonochemically nanotubes. Cyclic voltammetry measurements 1.0 M H2SO4 showed that more 100% active...

Functionalization of carbon nanotubes (CNTs) is important for enhancing deposition metal nanoparticles in the fabrication supported catalysts. A facile approach oxidizing CNTs presented using a sonochemical method to promote density surface functional groups. This was successfully employed previous study [J. Phys. Chem. B 2004, 108, 19255] prepare highly dispersed, high-loading Pt on as fuel cell X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, cyclic voltammetry,...

To create new catalyst materials for fuel cell applications, multiwalled carbon nanotubes (CNTs) were functionalized with CO, COC, COO, and COH groups using a sonochemical treatment method under acidic aqueous solution (HNO3/H2SO4) conditions to make them amenable deposition of highly dispersed, ∼4 nm diameter Pt nanoparticles. The Pt−CNT interface was probed X-ray photoelectron spectroscopy (XPS), extended absorption fine structure (EXAFS), Raman attenuated total reflection infrared...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFractal Morphology Analysis of Combustion-Generated Aggregates Using Angular Light Scattering and Electron Microscope ImagesUemit Koeylue, Yangchuan Xing, Daniel E. RosnerCite this: Langmuir 1995, 11, 12, 4848–4854Publication Date (Print):December 1, 1995Publication History Published online1 May 2002Published inissue 1 December 1995https://pubs.acs.org/doi/10.1021/la00012a043https://doi.org/10.1021/la00012a043research-articleACS PublicationsRequest...

Bimetallic Pt−Ru alloy catalysts have been demonstrated to be more active than pure Pt in the electrooxidation of methanol. We report here a study on nanoparticle supported sonochemically functionalized carbon nanotubes. The were prepared by directly reducing corresponding salts, K2PtCl4 and K2RuCl5, an ethylene glycol aqueous solution containing dispersed Three different Ru atomic ratios, namely, Pt53Ru47, Pt69Ru31, Pt77Ru23, for investigation compositional effects. It was shown that highly...

New Pt monolayer electrocatalysts were prepared using galvanic displacement of a copper deposited at underpotentials on Pd core. By performing underpotential deposition twice, two monolayers deposited, forming core−shell structure with double shells. The shells consist an outermost shell and sublayer Pd−Au alloy. It was found that by adjusting the compositions alloy sublayer, it is possible to mediate oxygen reduction reaction (ORR) activity catalysts. An 10% (atomic) Au be most active among...

Abstract To evaluate the role of planar defects in lead‐halide perovskites—cheap, versatile semiconducting materials—it is critical to examine their structure, including defects, at atomic scale and develop a detailed understanding impact on electronic properties. In this study, postsynthesis nanocrystal fusion, aberration‐corrected scanning transmission electron microscopy, first‐principles calculations are combined study nature different formed CsPbBr 3 nanocrystals. Two types prevalent...

Noncatalyzed and catalyzed electrochemical oxidations of multiwalled carbon nanotubes (CNTs) were studied with the aim to understand their durability as catalyst support in polymer electrolyte membrane (PEM) fuel cells. Bare Pt-deposited CNTs investigated sulfuric acid at a constant potential . Carbon black (CB, Vulcan XC-72R) was also under same experimental conditions. The carbons oxidized room temperature form thin-film electrodes time durations up Cyclic voltammetry used monitor surface...

We report a conductive TiO2 nanocoating on carbon nanotubes (CNTs) as Pt electrocatalyst support that shows significant enhancement in catalyst activity and durability for the oxygen reduction reaction. By using CNTs substrate nanocoating, nanoscale morphology of oxide was retained during heat treatment. After doping X-ray photoelectron spectroscopy suggests shift binding energy Ti 2p, implying suboxide formation. The absorption near-edge structure showed mid-edge post-edge up to 5010 eV,...

Sparsely populated, vertically aligned nitrogen doped carbon nanotube arrays (CNTAs) with dislocated-graphene stacking were grown directly on fiber papers and investigated as hierarchical air cathodes in hybrid Li-air batteries aqueous catholytes. The CNTAs made electrodeposited Ni nanocatalysts, followed by plasma-enhanced chemical vapor deposition. thus obtained can reach a population number density low ∼107 per cm2 the fibers, achieving an extremely high porosity of over 99% for active...

Aluminosilicate zeolite nanoparticles were synthesized in a water-in-oil solvent and applied as an adsorbent for tetracycline (TC) removal from aqueous solutions. The large specific surface area at 495.8 m2 g–1 confirms that the have mesopores. show excellent efficiency TC, achieving over 97% pH range of 4.70–7.17. A fast adsorption kinetics was observed, reaching equilibrium only 20 min following pseudo-second-order kinetic model. isotherm found to follow Langmuir model, with maximum...

Lead–halide perovskite nanocrystals (PNCs) have attracted much attention in recent years due to their outstanding optical properties. We report here a new chemical route for triggering postsynthetic growth of CsPbBr3 PNCs at room temperature via intentional depletion stabilizing ligands, resulting an immediate fusion the as-synthesized PNCs. Upon fusion, can grow from ca. 8 nm 60 lateral dimensions 48 h, reaching about 14 thickness. More importantly, it was found that fused significantly...

Magnetic nanoparticles were used to support an ATRP catalyst for the polymerization of methyl methacrylate (MMA) minimized adverse effect and easy separation. The nanoparticle-supported mediated a living/controlled radical MMA as effectively unsupported catalysts. With addition 22 mol % CuBr2, polymer molecular weights well-controlled with initiator efficiency 0.85 polydispersity lower than 1.2. supported catalysts could be easily separated/isolated using external magnetic field reused...

Carbon nanotubes (CNTs) have been investigated in recent years as a catalyst support for proton exchange membrane fuel cells. Improved activities were observed and attributed to metal-support interactions. We report study on the kinetics of methanol electro-oxidation CNT supported Pt-Ru alloy nanoparticles. Alloy catalysts with different compositions, Pt53Ru47/CNT, Pt69Ru31/CNT Pt77Ru23/CNT, prepared detail. Experiments conducted at various temperatures, electrode potentials, concentrations....

Coupling Pt with metal oxides has been shown to be an effective approach for catalyst durability enhancement in the methanol oxidation reaction (MOR). Here, we report tuning valence niobium oxide (NbOx) as a support by tin (SnO2) promoter mediate electrocatalysis MOR. The was designed consist of supported on SnO2-modified NbOx coated carbon black (Pt-TNb/C), which shows significantly enhanced electrochemical and activity MOR that are better than without SnO2 modification (Pt-Nb/C) those...

The formation/growth/coagulation/sintering of flame-generated inorganic aggregates at low particle volume fractions (O(10−1ppm)) was investigated. Al2O3 particles synthesized in a Al(CH3)3 (TMA)-seeded atmospheric pressure counterflow diffusion flame (CDF) fueled with CH4/O2/N2 were used as the model material/combustion system. Experimental techniques included thermocouple, laser light scattering (LLS) and thermophoretic sampling/Transmission Electron Microscopy (TEM). Local aggregate...

A new method was developed to prepare highly dispersed Pt nanoparticles on carbon black use as proton exchange membrane (PEM) fuel cell catalysts. This involves using a polymer, poly(vinylpyrrolidone) (PVP), prevent particle aggregation and thereby reduce nanoparticle sizes achieve high dispersion. It found that mediated by PVP are smaller than those obtained without have narrower size distribution. Well-dispersed with metal loadings from 5 35 wt % were (Vulcan XC-72R). well-dispersed could...

We report an effective approach to synthesize nanoscale Nb2O5 coated on carbon nanotubes (CNTs) and transform it at low temperatures the conductive form of NbO2. The latter, when used as a Pt electrocatalyst support, shows significant enhancement in catalyst activity durability oxygen reduction reaction (ORR). Direct phase transformation NbO2 often requires above 1000 °C. Here we show that this can be achieved much lower temperature (e.g. 700 °C) if niobium oxide is first activated with...

Lead halide perovskites have a rich landscape of structural and optical properties, which can be explored possibly controlled by applying high pressure. Despite several reports on high-pressure studies CsPbBr3 nanocrystals (NCs), there so far been no under pressure that incorporate planar defects. NCs with Ruddlesden–Popper (RP) faults, formed via post-synthetic fusion growth, are significantly larger in size than as-synthesized display exceptional emission stability. Here, we compare...