Javier B. Giorgi

Study of CO adsorption on crystalline-silica-supported palladium particles

Supported palladium particles have been studied using a recently developed crystalline silica film. The SiO2 film, as seen for the first time by scanning tunnelling microscopy (STM), is sufficiently flat to be used for model catalyst studies. Palladium particles grown on silica at room temperature are round and somewhat disordered as seen by STM, suggesting a strong interaction between the Pd particles and the silica support. The structural properties of the palladium particles were probed by CO adsorption at 90 K, and monitored by IRAS. The same general adsorption sites are observed for the Pd particles grown on silica as have previously been observed for crystalline Pd particles on alumina, however a larger fraction of on-top sites was observed on silica, indicative of the smaller and more disordered particles. These first results obtained for the Pd/SiO2/Mo(1 1 2) system are encouraging for the use of the crystalline SiO2 substrate as a model-catalyst support.

The binding of alkyl chains to β-cyclodextrin and ‘hydroxypropyl-β-cyclodextrin’

The strength of binding of aliphatic alcohols, alkanesulfonate ions and aryl alkanoates to ‘hydroxypropyl-β-cyclodextrin’ is very similar to that to unmodified β-cyclodextrin (β-CD). The clear inference is that both forms of β-CD bind these guests to the wider opening of the CD cavity that is surrounded by secondary hydroxy groups.

Visible Light Production of Hydrogen by Ablated Graphene: Water Splitting or Carbon Gasification?

Reduced graphene oxide modified by pulsed laser ablation causes water splitting under visible light illumination (532 nm). When the light source is a pulsed laser, water splitting is accompanied by carbon gasification (CO formation); however, conventional (LED) light sources produce water splitting exclusively.