Pt38 cluster on OH- and COOH-functionalised graphene as a model for Pt/C-catalysts.

The binding of a Pt38-cluster on pristine graphene, mono-vacancy graphene, OH- and COOH-functionalised graphene has been investigated using DFT-calculations. Graphene containing a mono-vacancy site or OH and COOH functional groups on graphene anchor the Pt38-cluster more strongly than pristine graphene. The most favoured adsorption geometry for the cluster depends on the number of Pt-C bonds generated and the required distortion of the interacting facet. Adsorption of the cluster is associated with charge transfer between (functionalised) graphene and the Pt38-cluster, a localised charge re-distribution within the cluster and shift in the d-band centre. The modified electronic properties of the supported Pt38-cluster would imply a change in the reactivity of these supported Pt38-clusters towards adsorbates depending on the type of defect present in the support.

Recent advances in the development of multiplexed nanophotonic biosensors.

The field of nanophotonics has advanced and can be utilized as a method to detect different infectious diseases. The introduction of multiplex nanophotonic diagnostics has enabled the speedy and simultaneous detection of viral infections and specific biomarkers. The quick reaction times, high sensitivity, and specificity of multiplex nanophotonic diagnostics enable real-time identification of viruses without the need for nucleic acid amplification. This review presents an overview of nanophotonic tools used to identify diseases and particular biomarkers. The paper also examines possible research areas for the development of unique, cutting-edge multiplex nanophotonic diagnostics capable of concurrently detecting various diseases or biomarkers/biomolecules. Furthermore, it discusses barriers to further advancement and offers insight into anticipated trends.

Interaction of graphene with FCC-Co(111).

One of the possible catalyst deactivation mechanisms in the Fischer-Tropsch synthesis is carbon deposition in the form of a graphene overlayer. Currently no information is available on the nature of the interaction of these layers with the surface. The adsorption of graphene on the FCC-Co(111) surface was therefore studied. A chemical interaction between the graphene sheet and the cobalt surface was observed as evidenced by the partial DOS and Bader charge analysis. The adsorption energy was found to be small when normalized per carbon atom, but becoming large for extended graphene sheets. Graphene removal from the surface via lifting or sliding was considered. The energy barrier for sliding a graphene sheet is lower than the barrier for lifting, but the energy barriers become significant when placed into the context of realistic catalytic surfaces in the nanometer range.

The nature of the oxidation states of gold on ZnO.

The interaction between gold in the 0, i, ii and iii oxidation states and the zinc-terminated ZnO(0001) surface is studied via the QM/MM electronic embedding method using density functional theory. The surface sites considered are the vacant zinc interstitial surface site (VZISS) and the bulk-terminated island site (BTIS). We find that on the VZISS, only Au(0) and Au(i) are stable oxidation states. However, all clusters of i to iii oxidation states are stable as substitutionals for Zn2+ in the bulk terminated island site. Au(OH)(x) complexes (x= 1-3) can adsorb exothermically onto the VZISS, indicating that higher oxidation states of gold can be stabilised at this site in the presence of hydroxyl groups. CO is used as a probe molecule to study the reactivity of Au in different oxidation states in VZISS and BTIS. In all cases, we find that the strongest binding of CO is to surface Au(i). Furthermore, CO binding onto Au(0) is stronger when the gold atom is adsorbed onto the VZISS compared to CO binding onto a gas phase neutral gold atom. These results indicate that the nature of the oxidation states of Au on ZnO(0001) will depend on the type of adsorption site. The role of ZnO in Au/ZnO catalysts is not, therefore, merely to disperse gold atoms/particles, but to also modify their electronic properties.