The decomposition of methanol catalyzed with Rh nanoclusters supported on an ordered thin film of Al2O3/NiAl­(100) became enhanced on decreasing the size of the clusters. The decomposition of methanol (and methanol-d 4) proceeded through dehydrogenation; the formation thereby of CO became evident above 200 K, depending little on the cluster size. In contrast, the production of CO and hydrogen (deuterium) from the reaction varied notably with the cluster size. The quantity of either CO or hydrogen produced per Rh surface site was unaltered on clusters of diameter >1.5 nm and height >0.6 nm, corresponding to about 65% of methanol undergoing decomposition on adsorption in a monolayer on the clusters. For clusters of diameter <1.5 nm and height <0.6 nm, the production per Rh surface site increased with decreasing size, up to 4 times that on the large clusters or Rh(100) single-crystal surface. The reactivity was enhanced largely because, with decreasing cluster size, the activation energy for the scission of the O–H bond in the initial dehydrogenation became smaller than the activation energy for the competing desorption. The property was associated with the edge Rh atoms at the surface of small clusters.

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The adsorption and lateral interactions of CO molecules on Rh nanoclusters supported on an ordered thin film of Al2O3/NiAl(100) altered with the size of the Rh clusters.

The dissociation of water molecules absorbed on a cleaved non-polar GaN(11[combining macron]00) surface was studied primarily with synchrotron-based photoemission spectra and density-functional-theory calculations. The adsorbed water molecules are spontaneously dissociated into hydrogen atoms and hydroxyl groups at either 300 or 130 K, which implies a negligible activation energy (<11 meV) for the dissociation. The produced H and OH were bound to the surface nitrogen and gallium on GaN(11[combining macron]00) respectively. These results highlight the promising applications of the non-polar GaN(11[combining macron]00) surface in water dissociation and hydrogen generation.

Pt and Rh nanoclusters, grown on deposition of Pt and Rh vapors onto graphene/Pt(111), show separate reactivity toward the decomposition of methanol-d4. The Pt (Rh) clusters had a mean diameter 2.0–3.5 nm (2.1–4.0 nm) and height 0.45–0.94 nm (0.41–0.9 nm) evolving with the coverage; they were structurally ordered, having an fcc phase and growing in (111) orientation, and had lattice constants similar to their bulk values. Methanol-d4 on the Pt clusters did not decompose but desorbed mostly, disparate from that on Pt(111) surface; the disparity arose as the adsorption energies of methanol-d4 on most surface sites of the Pt clusters became smaller than their single crystal counterpart. This size effect, nevertheless, did not apply on the Rh clusters, despite their similar atomic stacking; the Rh clusters showed a reactivity similar to that of the Rh(111) surface because the adsorption energies of methanol-d4 on both Rh clusters and Rh(111) are comparable. The distinct size dependence was rationalized through their electronic structures and charge distribution of Fukui function mapping. Our results suggest that reactive transition metals do not necessarily become more reactive while they are scaled down to nanoscale; their reactivity evolves with their size in a manner largely dependent on their electronic nature.

Impregnation of ILs on SBA-15 was successfully prepared in supercritical CO2. It was superior to the sample prepared using impregnation method.

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Atomic structures of Pt nanoclusters on graphene/Pt(111) were investigated with various techniques to probe the surface under ultrahighvacuum conditions and with calculations based on density-functional theory. Monolayer graphene was grown on thermal decomposition of ethylene on Pt(111) at 950 K and Pt clusters on the deposition of Pt vapor onto graphene/ Pt(111) at 300 K. The graphene had two predominant domains: one had a small angle of rotation between the graphene and the underlying Pt lattice, structurally commensurate with the Pt( 111) lattice (G 0°) , and the other was rotated about 30°with respect to the Pt lattice (G 30°) . G 0°h ad a slightly corrugated structure, involving tetrahedral hybridization, and a stronger adsorption on Pt(111); in contrast, G 30°w as flat and weakly bound to Pt(111) via a van der Waals interaction. The grown Pt clusters were structurally ordered, having a face-centered cubic phase and growing in a (111) orientation, whereas they had correspondingly disparate nucleation modes and rotational configurations on the two major graphene domains. On G 0°, the clusters were smaller and had a narrow size distribution and greater cluster density; they were structurally commensurate with the G 0°l attice (with their [−110] (or [0− 11]) axes along direction [1−100] of G 0°) . In contrast, on G 30°, the clusters were larger and had an evidently broader size distribution and smaller cluster density; they preferred to rotate by 30°relative to the underlying G 30°l attice. The former is attributed to a strong Pt−G 0°i nteraction, whereas the latter is only partly attributed to a weak Pt−G 30°i nteraction; the preferential rotation of Pt clusters on G 30°i s governed not only by the graphene lattice, but largely by an indirect interaction between the Pt substrate and the clusters, likely through the charge transferred from the Pt substrate to graphene.