CommunicationsPseudomorphic monolayers can be formed on single-crystal substrates by the deposition of palladium. Depending on the lattice parameters of the substrate, the palladium monolayer is compressed or dilated, effects which alter its properties, for example, the adsorption of hydrogen or the electrooxidation of formic acid. The changes in these properties can be studied electrochemically. For more information see the Communication by L. A. Kibler et al. on the following pages.
A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures (<500 °C) and exploited to enhance the catalytic activity of Pt/CeO -based exhaust gas catalysts. Redispersion of platinum in an oxidizing atmosphere already occurred at 400 °C. A protocol with reducing pulses at 250-400 °C was applied in a subsequent step for controlled Pt-particle formation. Operando X-ray absorption spectroscopy unraveled the different extent of reduction and sintering of Pt particles: The choice of the reductant allowed the tuning of the reduction degree/particle size and thus the catalytic activity (CO>H >C H ). This dynamic nature of Pt on ceria at such low temperatures (250-500 °C) was additionally confirmed by in situ environmental transmission electron microscopy. A general concept is proposed to adjust the noble metal dispersion (size, structure), for example, during operation of an exhaust gas catalyst.
A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures (<500 °C) and exploited to enhance the catalytic activity of Pt/CeO2‐based exhaust gas catalysts. Redispersion of platinum in an oxidizing atmosphere already occurred at 400 °C. A protocol with reducing pulses at 250–400 °C was applied in a subsequent step for controlled Pt‐particle formation. Operando X‐ray absorption spectroscopy unraveled the different extent of reduction and sintering of Pt particles: The choice of the reductant allowed the tuning of the reduction degree/particle size and thus the catalytic activity (CO>H2>C3H6). This dynamic nature of Pt on ceria at such low temperatures (250–500 °C) was additionally confirmed by in situ environmental transmission electron microscopy. A general concept is proposed to adjust the noble metal dispersion (size, structure), for example, during operation of an exhaust gas catalyst.
Polycrystalline Pt electrodes have been faceted by fast periodic potential scans. The electrocatalytic behavior of preferentially oriented ''Pt͑111͒'', ''Pt͑110͒'', and ''Pt͑100͒'' surfaces modified by Ru submonolayers was examined by cyclic voltammetry and chronoamperometry. The enhancement factor for methanol electro-oxidation depends on the surface crystallography and on the Ru coverage. The optimum Ru coverage at room temperature was found to be 30-40% of a monolayer for all electrodes under study. The catalytic activity of the Ru/''Pt͑hkl͒'', electrodes for methanol oxidation was compared with that of Ru/Pt͑111͒. The catalytic activity at optimum Ru coverage decreases in the following order: ''Pt͑111͒'' Ͼ ''Pt͑110͒'' Ͼ Pt͑111͒ Ͼ ''Pt͑100͒''. The reactivity of the Ru/''Pt͑hkl͒'' electrodes for methanol oxidation can be attributed to the high number of steps and defect sites on their surfaces.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.