Oxygen-rich Ti1−xO2 pillar growth at a gold nanoparticle–TiO2 contact by O2 exposure

Abstract In-situ gas-injection transmission electron microscopy revealed that a pillar grew at the edge of the interface of a gold nanoparticle and a TiO 2 substrate during exposure to O 2 gas at 100 Pa. The pillar was found to have a titanium-deficient chemical composition of Ti 1 −  x O 2 ( x  > 0) by electron energy loss spectroscopy (EELS). The spectra showed a chemical shift of oxygen and titanium ions to have ionic states of Ti 3+ and O y − ( y 1 −  x O 2 at the contact edge of gold–Ti 1 −  x O 2 interface is discussed from the perspective of an O 2 affinity, which plays an important role in CO oxidation process of supported gold particle.