Highly Efficient and Selective Oxidation of Ethanol to Acetaldehyde by a Hybrid Photocatalyst Consisting of SnO2 Nanorod and Rutile TiO2 with Heteroepitaxial Junction.

Single-crystal SnO2 nanorods were grown on rutile TiO2 with a heteroepitaxial relation of SnO2 {001}/TiO2 {001} (SnO2 -NR#TiO2 ) by a hydrothermal reaction. Resulting compressive lattice strain in the SnO2 -NR near the interface induces a continuous increase in the a-axis length extending over 60 nm to relax towards the [001] direction from the root to the tip. UV-light irradiation of the robust SnO2 -NR#TiO2 stably progresses the selective oxidation of ethanol to acetaldehyde with an external quantum yield of 25.6 % at excitation wavelength (λex )=365 nm under ambient temperature and pressure. Spectroscopic analyses and density functional theory simulation results suggested that the extremely high photocatalytic activity stems from the smooth interfacial electron transfer from TiO2 to SnO2 -NR through the high-quality junction and subsequent efficient charge separation due to the lattice strain-induced unidirectional potential gradient of the conduction band minimum in the SnO2 -NR.

Hydrogen peroxide synthesis from water and oxygen using a three-component nanohybrid photocatalyst consisting of Au particle-loaded rutile TiO2 and RuO2 with a heteroepitaxial junction.

Thin heteroepitaxial (HEPI) layers of RuO2 were selectively formed on the TiO2 surface of Au nanoparticle-loaded rutile TiO2 particles (RuO2#TiO2-Au) with an orientation of RuO2(110)//TiO2(110) by a hydrothermal method, and the three-component nanohybrid exhibits a high photocatalytic activity far exceeding that of Au/TiO2 for hydrogen peroxide generation from water and oxygen due to the HEPI junction-induced unique morphology of RuO2.