Unusual synergistic effect in layered Ruddlesden-Popper oxide enables ultrafast hydrogen evolution

Efficient electrocatalysts for hydrogen evolution reaction are key to realize clean hydrogen production through water splitting. As an important family of functional materials, transition metal oxides are generally believed inactive towards hydrogen evolution reaction, although many of them show high activity for oxygen evolution reaction. Here we report the remarkable electrocatalytic activity for hydrogen evolution reaction of a layered metal oxide, Ruddlesden-Popper-type Sr2RuO4 with alternative perovskite layer and rock-salt SrO layer, in an alkaline solution, which is comparable to those of the best electrocatalysts ever reported. By theoretical calculations, such excellent activity is attributed mainly to an unusual synergistic effect in the layered structure, whereby the (001) SrO-terminated surface cleaved in rock-salt layer facilitates a barrier-free water dissociation while the active apical oxygen site in perovskite layer promotes favorable hydrogen adsorption and evolution. Moreover, the activity of such layered oxide can be further improved by electrochemistry-induced activation

The Role of Surface Defects in the Adsorption of Methanol on Fe3O4(001)

The adsorption of methanol (CH3OH) at the Fe3O4(001)−(√2 × √2)R45° surface was studied using X-ray photoelectron spectroscopy, scanning tunneling microscopy, and temperature-programmed desorption (TPD). CH3OH adsorbs exclusively at surface defect sites at room temperature to form hydroxyl groups and methoxy (CH3O) species. Active sites are identified as step edges, iron adatoms, antiphase domain boundaries in the (√2 × √2)R45° reconstruction, and above Fe atoms incorporated in the subsurface. In TPD, recombinative desorption is observed around 300 K, and a disproportionation reaction to form methanol and formaldehyde occurs at 470 K.Austrian Science Fund START prizeAustrian Science Fund (FWF)AustrianScience Fund (FWF) SOLIDS4FUN4204301

chapter 10 Thin oxide films as model systems for heterogeneous catalysts

This chapter summarizes efforts to use thin oxide films as model supports for heterogeneous catalysts. We demonstrate that the oxide film route provides a useful platform to study oxide surfaces, per se its interaction with species from the gas phase, supported metal and oxide nanoparticles using the entire tool box of surfaces science under ultrahigh vacuum conditions. The extension to use thin oxide films as template also under ambient conditions or under water, is discussed and the potential to use oxide films as genuine two-dimensional materials is exemplified with vitreous and crystalline silica films