Chemically made, atomically precise phosphine-stabilized clusters Au9(PPh3)8(NO3)3 were deposited on titania and silica from solutions at various concentrations and the samples heated under vacuum to remove the ligands. Metastable induced electron spectroscopy was used to determine the density of states at the surface, and X-ray photoelectron spectroscopy for analysing the composition of the surface. It was found for the Au9 cluster deposited on titania that the ligands react with the titania substrate. Based on analysis using the singular value decomposition algorithm, the series of MIE spectra can be described as a linear combination of 3 base spectra that are assigned to the spectra of the substrate, the phosphine ligands on the substrate, and the Au clusters anchored to titania after removal of the ligands. On silica, the Au clusters show significant agglomeration after heat treatment and no interaction of the ligands with the substrate can be identified.

Triphenylphosphine ligand-protected Au9 clusters deposited onto titania nanosheets show three different atomic configurations as observed by scanning transmission electron microscopy. The configurations observed are a 3-dimensional structure, corresponding to the previously proposed Au9 core of the clusters, and two pseudo-2-dimensional (pseudo-2D) structures, newly found by this work. With the help of density functional theory (DFT) calculations, the observed pseudo-2D structures are attributed to the low energy, de-ligated structures formed through interaction with the substrate. The combination of scanning transmission electron microscopy with DFT calculations thus allows identifying whether or not the deposited Au9 clusters have been de-ligated in the deposition process.

The far infra-red absorption spectra of a series of chemically synthesised, atomically precise phosphinestabilised gold cluster compounds have been recorded using synchrotron light for the first time. Far-IR spectra of the Au 6 (Ph 2 P(CH 2 ) 3 PPh 2 ) 4 (NO 3 ) 2 , Au 8 (PPh 3 ) 8 (NO 3 ) 2 , Au 9 (PPh 3 ) 8 (NO 3 ) 3 , and Pd(PPh 3 ) Au 6 (PPh 3 ) 6 (NO 3 ) 2 clusters reveal a complex series of peaks between 80 and 475 cm À1 , for which all significant peaks can be unambiguously assigned by comparison with Density Functional Theory (DFT) geometry optimisations and frequency calculation. Strong absorptions in all spectra near 420 cm À1 are assigned to the P-Ph 3 stretching vibrations. Distinct peaks within the spectrum of each specific cluster are assigned to the cluster core vibrations: 80.4 and 84.1 cm À1 (Au 6 ) 165.1 and 166.4 cm À1 (Au 8 ), 170.1 and 185.2 cm À1 (Au 9 ), and 158.9, 195.2, and 206.7 cm À1 (Au 6 Pd). The positions of these peaks are similar to those observed to occur for the neutral Au 7 cluster in the gas phase (Science, 2008, 321, 674-676). Au-P stretching vibrations only occur for Au 6 near 420 cm À1 , although they appear near 180 cm À1 for Au 6 Pd and involve gold core vibrations.

High-quality far-IR absorption spectra for a series of ligated atomically precise clusters containing Ru3, Ru4, and AuRu3 metal cores have been observed using synchrotron radiation, the latter two for the first time. The experimental spectra are compared with predicted IR spectra obtained following complete geometric optimization of the full cluster, including all ligands, using DFT. We find strong correlations between the experimental and predicted transitions for the low-frequency, low-intensity metal core vibrations as well as the higher frequency and intensity metal-ligand vibrations. The metal core vibrational bands appear at 150 cm(-1) for Ru3(CO)12, and 153 and 170 cm(-1) for H4Ru4(CO)12, while for the bimetallic Ru3(μ-AuPPh3)(μ-Cl)(CO)10 cluster these are shifted to 177 and 299 cm(-1) as a result of significant restructuring of the metal core and changes in chemical composition. The computationally predicted IR spectra also reveal the expected atomic motions giving rise to the intense peaks of metal-ligand vibrations at ca. 590 cm(-1) for Ru3, 580 cm(-1) for Ru4, and 560 cm(-1) for AuRu3. The obtained correlations allow an unambiguous identification of the key vibrational modes in the experimental far-IR spectra of these clusters for the first time.

Indium-tin-oxide (ITO) electrode surfaces were modified using thin polymeric films of ethoxylated polyethylenimine (PEIE) and poly(3,3′-([(9′,9′-dioctyl-9H,9′H-[2,2′-bifluorene]-9,9-diyl)bis(4,1-phenylene)]bis(oxy))bis(N,N-dimethylpropan-1-amine)) (PFPA-1) to investigate the resultant work function and its stability in ambient atmosphere. Both PEIE and PFPA-1 were found to significantly reduce the ITO work function, as a result of a surface dipole at the ITO–polymer interface. After aging for two weeks in ambient air atmosphere, the N-side groups and OH groups in PEIE-modified ITO were found to realign themselves away from the polymer surface, resulting in an orientation more parallel to the surface normal and thus in an increase in work function from 3.5 to 3.8 eV. The work function of PFPA-1-modified ITO was found to increase from 3.65 to 4.1 eV after two weeks of aging in air due to a complete re-orientation of the polar side chains away from the surface, aligning the dipoles more parallel to the surface normal. In both PEIE and PFPA-1 samples, the hydrophobic aliphatic carbon was found to dominate the polymer surface, after aging.

Bubbles have been formed from solutions of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) in formamide. The bubbles were transferred onto a hydrophobic substrate after drainage time of 0−20 min. Drainage time of 20 min is sufficient to generate fully drained bubbles. The structure of the transferred films was investigated with X-ray photoelectron spectroscopy and metastable induced electron spectroscopy. Films transferred after a drainage time of 5 min or less show random orientation of the molecules in the films. Films transferred after a drainage time of 10 min or longer result in films forming a mixture of two different types of structures. The smaller fraction of the transferred film shows random orientation of the molecules. The larger fraction shows preferred orientation of the POPC molecules. In the fraction with preferred orientation the polar part of the POPC molecules forms to a large degree the outermost layer which is different to surfaces of surfactant solutions and to the surface of foam films formed by surfactant molecules. A surface formed by polar groups has a higher surface energy than a film formed by nonpolar groups. The possible reasons for the orientation of the molecules with the polar group pointing to the surface are discussed.

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A high-temperature, high-pressure, pulsed-gas sampling and detection system has been developed for testing new catalytic and photocatalytic materials for the production of solar fuels. The reactor is fitted with a sapphire window to allow the irradiation of photocatalytic samples from a lamp or solar simulator light source. The reactor has a volume of only 3.80 ml allowing for the investigation of very small quantities of a catalytic material, down to 1 mg. The stainless steel construction allows the cell to be heated to 350 °C and can withstand pressures up to 27 bar, limited only by the sapphire window. High-pressure sampling is made possible by a computer controlled pulsed valve that delivers precise gas flow, enabling catalytic reactions to be monitored across a wide range of pressures. A residual gas analyser mass spectrometer forms a part of the detection system, which is able to provide a rapid, real-time analysis of the gas composition within the photocatalytic reaction chamber. This apparatus is ideal for investigating a number of industrially relevant reactions including photocatalytic water splitting and CO reduction. Initial catalytic results using Pt-doped and Ru nanoparticle-doped TiO as benchmark experiments are presented.