Topic
Platinum
About: Platinum is a research topic. Over the lifetime, 49675 publications have been published within this topic receiving 1150035 citations. The topic is also known as: Pt & element 78.
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TL;DR: In this paper, the effects of electrode surface oxide on the oxidation reactions of phenol and on electrode passivation by reaction products were investigated using cyclic voltammetry and chronoamperometry.
Abstract: The oxidation of phenol at the platinum electrode was studied in aqueous acidic solutions. The effects of electrode surface oxide on the oxidation reactions of phenol and on electrode passivation by reaction products were investigated using cyclic voltammetry and chronoamperometry. X‐ray photoelectron spectrometry was used to detect changes in the nature of the passive film. Phenol reacted at both the inner and outer Helmholtz layers at platinum metal electrodes. Phenol in the inner Helmholtz layer is adsorbed irreversibly and is conductive. Its oxidation involves ring cleavage with a greater than 18 eq/mol. The outer Helmholtz layer reactions are characterized by rapid simple oxidations involving minimal rearrangement of the reactant molecule. This implies that once stable oxidized products such as benzoquinone and polymers with quinone or ether structures are formed they must move from the outer to the inner Helmholtz layer to be oxidized further by ring‐cleavage reactions. We postulate that the bulk of the initial current flow during phenol oxidation is due to the simple fast outer Helmholtz reactions. This initial current continues until the buildup of unreactive products blocks further outer Helmholtz reactions and the slower inner layer reactions predominate. This electrode behavior changed if the electrode was preoxidized producing a platinum oxide coating. The inner layer reactions were greatly reduced at a platinum oxide coated electrode resulting in lower passivated electrode current flow. The onset of passivation however was delayed at the oxide coated electrode. This is attributed to a weaker adsorption of reaction products at the electrode surface requiring additional reaction to produce a stable passive film. The final resulting passive films at platinum and platinum oxide electrodes were chemically similar based on x‐ray photoelectron spectrometric analysis but differed in thickness indicating that the electrode passivation is not due simply to the thickness of the passive film.
217 citations
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TL;DR: In this article, the thermal decomposition behavior of poly(N-vinyl-2-pyrrolidone) (PVP) on platinum (Pt) is investigated.
Abstract: TG-DTA, TEM, and IR were used to investigate the thermal decomposition behavior of poly(N-vinyl-2-pyrrolidone) (PVP). The TG-DTA results show that the thermal decomposition behavior of PVP on platinum (Pt) is quite different from that of pure PVP. For pure PVP, 95.25% is decomposed when the temperature is increased up to 500°C; while under the same experimental condition, PVP coated on the Pt nanoparticles is only 66.7% decomposed. This is further supported by IR measurement. TEM results exhibited that the partially decomposed PVP still plays a role in stabilizing Pt nanoparticles: after heating treatment at 500°C for half an hour, the platinum nanoparticles did not aggregate heavily. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 23–26, 2006
217 citations
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TL;DR: In this article, a polypyrrole containing the toluenesulphonate counter-ion has been electrochemically polymerized on a wide range of metallic electrodes, including platinum, titanium, aluminium, mild steel and brass.
217 citations
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TL;DR: The results show that the NCNTs intrinsically display excellent catalytic activity for oxygen reduction in fuel cells, comparable to traditional platinum-based catalysts, and exhibit outstanding stability, selectivity, and resistance to CO poisoning, much superior to the platinum- based catalysts.
Abstract: Nitrogen atoms were found to exhibit a strong ability to promote the self-assembly of nitrogen-doped carbon nanotubes (NCNTs) from gaseous carbons, without an assistance of metal atoms. On the basis of this discovery, pure metal-free CNTs with a nitrogen-doping level as high as 20 atom % can be directly synthesized using melamine as a C/N precursor. This offers a novel pathway for carbon nanotube synthesis. Furthermore, the metal-free and intact characteristics of the NCNT samples facilitate a clear verification of the intrinsic catalytic ability of NCNTs. The results show that the NCNTs intrinsically display excellent catalytic activity for oxygen reduction in fuel cells, comparable to traditional platinum-based catalysts. More notably, they exhibit outstanding stability, selectivity, and resistance to CO poisoning, much superior to the platinum-based catalysts.
217 citations
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TL;DR: In this article, a photochemical solid-phase reduction method was proposed to fabricate well-defined isolated Pt atoms on a nitrogen-doped porous carbon (Pt1/NPC).
Abstract: Currently, Pt single atoms as promising electrocatalysts have been applied to electrocatalysis aiming to significantly improve performance and remarkably lower usage of the noble metal. Herein, we propose a photochemical solid-phase reduction method to fabricate well-defined isolated Pt atoms on a nitrogen-doped porous carbon (Pt1/NPC). Using this simple and fast synthesis strategy, the formed Pt atoms are well-dispersed on the carbon without clusters or nanoparticles. The loading of the Pt is up to 3.8 wt % relative to the carbon. The Pt1/NPC catalyst displays an ultrahigh electrocatalytic activity for hydrogen evolution reaction with an overpotential of 25 mV at the current density of 10 mA cm–2 and mass activity of 2.86 A mg–1 Pt (24-times higher than a commercial Pt/C). Moreover, the catalyst also presents efficient catalytic activity for the oxygen reduction reaction. Its mass activity is 4.3-times that obtained by a commercial Pt (20 wt %). The improved electrocatalytic activities of the Pt1/NPC cat...
217 citations