TY - CONF

T1 - Monodisperse tungsten oxide cluster deposition from solution

T2 - 66th Annual Meeting of the Austrian Physical Society

AU - Müllner, Matthias

AU - Balajka, Jan

AU - Schmid, Michael

AU - Diebold, Ulrike

AU - Mertens, Stijn F. L.

AU - Hemmi, Adrian

N1 - Conference code: 66

PY - 2016/9/26

Y1 - 2016/9/26

N2 - Perfectly monodisperse clusters of oxides are critically importantmodel systems for catalysis studies because they allow the rigorousanalysis of reaction mechanisms, and variations at the single-atomlevel can already be reflected in their reactivity. The generation andintact immobilisation on a suitable substrate of such clusters is quitechallenging, and usually requires mass spectrometric size selection and sophisticated soft landing protocols to make such studies successful.Tungsten (VI) oxide in particular holds promise as a visible-light photocatalyst, but is quite reactive and can be challenging to immobilise ina well-defined manner in vacuum [1].Here, we present a solution-based protocol for the preparation ofmonodisperse cyclic tris (tungsten (VI) trioxide) clusters, (WO3) 3. Theclusters can be harvested efficiently on the boron nitride nanomesh[2], an atomically thin layer of hexagonal boron nitride on Rh (111) withstrong corrugation, and a promising platform for self-assembly [3] andelectrochemical functionality [4]. The triangular (WO3) 3 clusters adsorbin the ‚pores‘ of the nanomesh, where they were imaged with submolecular resolution using electrochemical scanning tunnelling microscopy.The decorated surface was transferred to vacuum where the chemicalidentity of the clusters was confirmed with XPS. To our knowledge, this is the first successful example of self-assembly on the nanomesh fromsolution. We expect that proper control over deposition conditions willallow tuning of the number of clusters per pore, making this a promising model system for on-surface catalysis studies.We contrast this finding with deposition of the same source materialon rutile TiO2 (110) in liquid, on which the clusters appear to react andform chains, akin to some observations of sublimated WO3 in vacuum[5]. Even though the clusters are likely hydroxylated in aqueous solution, this behaviour indicates surprising parallels with UHV and suggeststhat, in many cases, solution-based procedures complement vacuummethods.

AB - Perfectly monodisperse clusters of oxides are critically importantmodel systems for catalysis studies because they allow the rigorousanalysis of reaction mechanisms, and variations at the single-atomlevel can already be reflected in their reactivity. The generation andintact immobilisation on a suitable substrate of such clusters is quitechallenging, and usually requires mass spectrometric size selection and sophisticated soft landing protocols to make such studies successful.Tungsten (VI) oxide in particular holds promise as a visible-light photocatalyst, but is quite reactive and can be challenging to immobilise ina well-defined manner in vacuum [1].Here, we present a solution-based protocol for the preparation ofmonodisperse cyclic tris (tungsten (VI) trioxide) clusters, (WO3) 3. Theclusters can be harvested efficiently on the boron nitride nanomesh[2], an atomically thin layer of hexagonal boron nitride on Rh (111) withstrong corrugation, and a promising platform for self-assembly [3] andelectrochemical functionality [4]. The triangular (WO3) 3 clusters adsorbin the ‚pores‘ of the nanomesh, where they were imaged with submolecular resolution using electrochemical scanning tunnelling microscopy.The decorated surface was transferred to vacuum where the chemicalidentity of the clusters was confirmed with XPS. To our knowledge, this is the first successful example of self-assembly on the nanomesh fromsolution. We expect that proper control over deposition conditions willallow tuning of the number of clusters per pore, making this a promising model system for on-surface catalysis studies.We contrast this finding with deposition of the same source materialon rutile TiO2 (110) in liquid, on which the clusters appear to react andform chains, akin to some observations of sublimated WO3 in vacuum[5]. Even though the clusters are likely hydroxylated in aqueous solution, this behaviour indicates surprising parallels with UHV and suggeststhat, in many cases, solution-based procedures complement vacuummethods.

M3 - Conference paper

SP - 267

EP - 268

Y2 - 27 September 2016 through 29 September 2016

ER -