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Surface templating by electrostatic surface potentials is the least invasive way to design large-scale artificial nanostructures. However, generating sufficiently large potential gradients remains challenging. Here, we lay the groundwork for significantly enhancing local electrostatic fields by chemical modification of the surface. We consider the hexagonal boron nitride (h-BN) nanomesh on Rh(111), which already exhibits small surface potential gradients between its pore and wire regions. Using photoemission spectroscopy, we show that adding Au atoms to the Rh(111) surface layer leads to a local migration of Au atoms below the wire regions of the nanomesh. This significantly increases the local work function difference between the pore and wire regions that can be quantified experimentally by the changes in the h-BN valence band structure. Using density functional theory, we identify an electron transfer from Rh to Au as the microscopic origin for the local enhancement of potential gradients within the h-BN nanomesh. [ABSTRACT FROM AUTHOR]

Auger electron spectroscopy, high-resolution electron energy loss spectroscopy and temperature programmed desorption methods have been used in order to investigate the adsorption properties and reactions of acetaldehyde on gold decorated rhodium and BN/Rh(111) surfaces. Scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements were carried out to characterize the gold nanoparticles on clean and hexagonal boron nitride (h-BN) covered Rh(111). The adsorption of acetaldehyde was not completely hindered by gold atoms; however, depending on the structure of the outermost bimetallic layer (surface alloy) the dissociation of the parent molecule was suppressed, namely the production of carbon monoxide was inhibited by the gold domains. Our measurements with acetaldehyde on Au/h-BN/Rh(111) confirmed the observation that the lack of suitable adsorption sites eliminates the formation of CO. Nevertheless, increased coverage of gold enhanced the amount of adsorbed aldehyde at low temperature. We may predict that the low reactivity of acetaldehyde on Au/h-BN/Rh(111) significantly determine the ethanol decomposition mechanism on this surface. [ABSTRACT FROM AUTHOR]