Photocatalytic dehydrogenation of cis-1,4-cyclohexanediamine on Pd- and Au-deposited TiO2(110) surface

Abstract

Hydrogen can be stored in a liquid organic hydrogen carrier (LOHC) in a form of chemical bond with carbon. We can stably store or release the hydrogen gas by forming or breaking these bonds in LOHC molecules. Most of recently studied LOHC molecules rely their hydrogen storage ability on the cyclohexane-benzene transformation. However, it is hard to break the C-H bond of cyclohexane therefore requires catalysts and high temperature. In this study, we investigated the photocatalytic dehydrogenation of cis-1,4-cyclohexanediamine on Pd- and Au-deposited rutile TiO2(110) single crystal surface by low-temperature scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic dissociation of C-H bond by 365 nm wavelength UV irradiation is observed on the Pd- and Au-deposited TiO2, but not on the bare TiO2 surface. We showed the metal-induced change in the electronic structure on TiO2(110) surface and suggested that the reaction is induced by the hot electrons, produced by the dielectric response of the TiO2(110) against the plasmonic metal nanoparticles.