TiOxHy

TiOxHy refers to a family of titanium-containing oxides that also incorporate hydrogen, described by a general formula involving titanium with varying amounts of oxygen and hydrogen. Unlike a single compound, TiOxHy represents non-stoichiometric phases where hydrogen can occupy interstitial sites or substitute in the lattice, and where oxygen vacancies may coexist. The exact composition and structure depend on how the material is synthesized and processed.

In TiOxHy, hydrogen incorporation affects the electronic structure and local bonding. Hydrogen can donate electrons to the titanium-oxygen framework, potentially reducing some Ti4+ to Ti3+ and altering conductivity, color, and defect chemistry. The presence of hydrogen and oxygen vacancies can distort the lattice and create new defect-related states, which influence transport properties, optical absorption, and chemical reactivity. These materials often sit at the intersection of oxide chemistry and hydride-like chemistry, yielding behaviors distinct from pure TiO2 or bulk titanium hydrides.

Synthesis of TiOxHy generally involves hydrogenation or reduction of titanium oxides under hydrogen-containing atmospheres, sometimes combined with electrochemical intercalation, hydrothermal treatment, or plasma exposure. The resulting phases range from partially hydrogenated oxides to more hydride-rich species, with the exact phase diagram governed by temperature, pressure, and the hydrogen activity during synthesis.

Characterization typically uses X-ray and neutron diffraction to determine structure, X-ray photoelectron spectroscopy for oxidation states, Raman and infrared spectroscopy for bonding, and electron microscopy for morphology. Electrical conductivity and hydrogen storage capacity measurements are also common, as researchers explore potential applications in energy storage, photocatalysis, and electrochemical devices.

Safety considerations include handling hydrogen-containing materials carefully, as hydrogen release or recombination at certain conditions can pose risks.