Sol−Gel Prepared Pt-Modified Oxide Layers:  Synthesis, Characterization, and Electrocatalytic Activity

Abstract

Thin films of pure RuO2 and IrO2 and mixed Ru0.5Ir0.5O2 oxide modified with Pt particles were prepared by a sol−gel method in the form of thin films of ∼2 μm thickness on Ti substrates. Surface morphology of these Pt-modified oxides was examined by scanning electron microscopy and was found to exhibit a significant influence of the chemical composition of the oxide matrix. Element mapping showed homogeneous distribution of the metals. X-ray diffraction and X-ray photoelectron spectroscopy analyses showed that these films consist of metallic Pt particles dispersed in an oxide matrix. Cyclic voltammetry in acid solutions showed that the sol−gel prepared layers have relatively high Pt surface areas. The electrocatalytic activity of these materials toward the anodic oxidation of formaldehyde and methanol was compared in terms of onset potential and current density and was found to follow the sequence: Pt−Ru0.5Ir0.5O2/Ti > Pt−RuO2/Ti > Pt−IrO2/Ti.

Direct methanol oxidation at low overpotentials using Pt nanoparticles electrodeposited at ultrathin conductive RuO2 nanoskins

“…28 Carbon monoxide oxidation is also used to investigate the promotional effects of Ru in PtRu nanoparticle electrocatalysts, 29,30 as well as that of hydrated or hydrous RuO 2 toward electrocatalytic oxidation at ruthenium oxide-supported Pt nanoparticles. 9,31,32 The electrochemical oxidation of CO adsorbed at Pt nanoparticles presumably obeys the Langmuir-Hinshelwood reaction mechanism, 28 as proposed elsewhere for Pt surfaces:…”

“…3,5,6 The importance of hydrated RuO 2 in the activation of Pt electrocatalysts for direct methanol oxidation was demonstrated by Rolison and coworkers when they proved that the most active form of nanoscale, bimetallic PtRu is not the Pt a Ru b alloy, but a physicochemically complex, phase-separated mix of a metallic Pt core carpeted by hydrous ruthenium oxide, with some platinum oxides present and very little, if any, part being played by metallic ruthenium. 3,6,7 Subsequently, Villullas et al 8,9 and Suffredini et al 10 showed that sol-gel-derived RuO 2 activates the electrocatalytic oxidation of CH 3 OH at Pt nanoparticles (2-4 nm), while Profeti et al demonstrated similar activating effects for RuO 2 derived from polymeric precursors that featured a hydrated form of rutile RuO 2 . 11 The common thread among these forms of RuO 2 is that they all are hydrous or water-sorbing oxides, and are thus water-activating support materials.…”

Nano silver imprinted graphene oxide as catalyst in reduction of 4‐nitrophenol

“…Hence, the choosing of suitable nanocatalyst is necessary to achieve outstanding catalytic behaviour for conversion of 4‐NP to 4‐aminophenol. For this purpose, different metal nanoparticles are established that exhibit high catalytic activity due to small size . Among them, noble metal nanoparticle, especially silver nanoparticle, is used as an excellent catalyst for production of 4‐AP from 4‐NP along with other catalysed reactions such as oxidation of methanol and oxidation of D‐glucose due to their high reactivity .…”

Enhancement of ethanol oxidation on Pd nanoparticles supported on carbon-antimony tin oxide hybrids unveils the relevance of electronic effects

“…Numerous studies were dedicated to the search for more efficient catalysts over the last decades, mostly in acid environments and mainly involving alloying Pt with transition metals [2]. Some studies also demonstrated that transition-metal oxides as co-catalysts or supports can enhance the activity of Pt nanoparticles for the oxidation of small organic molecules in acid media [3][4][5][6]. These effects were often interpreted as associated with the presence of OH groups on the oxide surface [7], which would favor the bifunctional mechanism [5,6].…”