Synchrotron XPS was used to investigate a series of chemically synthesised, atomically precise gold clusters Au(n)(PPh3)y (n = 8, 9 and 101, y depending on the cluster size) immobilized on anatase (titania) nanoparticles. Effects of post-deposition treatments were investigated by comparison of untreated samples with analogues that have been heat treated at 200 °C in O2, or in O2 followed by H2 atmosphere. XPS data shows that the phosphine ligands are oxidised upon heat treatment in O2. From the position of the Au 4f(7/2) peak it can be concluded that the clusters partially agglomerate immediately upon deposition. Heating in oxygen, and subsequently in hydrogen, leads to further agglomeration of the gold clusters. It is found that the pre-treatment plays a crucial role in the removal of ligands and agglomeration of the clusters.

Well-definedAu−TiO 2 materials were synthesized by deposition of triphenylphosphine-protected Au 9 clusters on TiO 2 (Aeroxide P-25), pre-treated in eight different ways and subsequently exposed to two post-treatments. X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy studies showed that in most cases the PPh 3 ligand shell was removed upon deposition even before post-treatment, coinciding with some cluster aggregation. However, clusters deposited on TiO 2 treated using H 2 SO 4 and H 2 O 2 showed remarkable resistance to aggregation, even after high-temperature calcination, while clusters on H 2 -treated TiO 2 showed the greatest resistance to aggregation under ozonolysis.

Crystalline titanium dioxide was synthesised under mild conditions by the thermal degradation of peroxotitanic acid in the presence of a number of fluoride-containing surface modifying agents (NH 4 F, NH 4 BF 4 , NH 4 PF 6 , NBu 4 F, NBu 4 BF 4 , NBu 4 PF 6). The resulting materials were characterised by PXRD, SEM, HRTEM, XPS and NEXAFS. Particle phase, size, and surface area were noticeably affected by the choice of surface modifying agent. Both the cation and anion comprising the modifying agent affect the surface Ti 3+ population of the materials, with two apparent trends observed: F À > BF 4 À > PF 6 À and NBu 4 + > NH 4 +. All materials displayed evidence of fluorine doping on their surfaces, although no evidence of bulk doping was observed.

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The photocatalytic decolorization and degradation of an anthraquinone-based reactive dye, C.I. Reactive Blue 19, was carried out in laboratory-scale experiments with the systematic variation of several operational parameters, including electron acceptor (hydrogen peroxide) concentration, initial pH, use of buffer solution, aeration, and the specific chemical nature of the buffer solution. Photodegradation was performed under simulated natural light, and conditions were chosen to mimic those found in industry. Mineralization and decolorization were monitored by UV-vis spectroscopy and total organic carbon analysis, and kinetics were modelled using an in-series first-order combination mechanism. Reaction products were examined and monitored by high-resolution mass spectrometry. Under the conditions explored, the reaction rate was found to depend not only on pH and electron acceptor concentration, but also on the specific chemical nature of the buffer used.

The polymer cell method (MPC) ‐ a new method to determine solubility o f disperse dyes, applicable between 80° and 140°C is described. This method is compared to the pressure filtration method. The results obtained using the two methods were found to be in good agreement. The application of the MPC method for determining solubility was investigated in the presence of levelling agents (Palegal A, B, HT, Sandogen PES, Invalon HTB) and was used to study the dyeing equilibria of a two‐step mechanism of disperse dyeing, i.e. dissolution of the dye dispersion and sorption of it by the substrate.

Bimetallic metal nanoparticles are often more catalytically active than their monometallic counterparts, due to a so-called ‘synergistic effect’. Atomically precise ruthenium-platinum clusters have been shown to be active in the hydrogenation of phenylacetylene to styrene (a reaction of importance to the polymer industry). However, the synthesis of these clusters is generally complex, and cannot be modified to produce clusters with differing metal compositions or ratios. Hence, any truly systematic study of compositional effects using such clusters is hindered by the inaccessibility of certain metal ratios. In this study, a series of larger bimetallic ruthenium-platinum colloids of varying metal ratios was synthesised in solution and immobilised on silica. Catalytic activity was evaluated by hydrogenation of phenylacetylene to styrene. Both bimetallic and monometallic colloids were active catalysts for the hydrogenation of phenylacetylene to styrene and further to ethylbenzene. Of those studied, a catalyst composed of 73 % platinum-27 % ruthenium (by moles) showed the highest activity. This suggests that synergistic effects play an important role in the catalysis of this reaction. To our knowledge this is the first systematic study of ruthenium-platinum nanoparticle catalytic activity on this reaction.

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