LaTiO2N

LaTiO2N is a mixed-anion compound that belongs to the family of oxynitrides. It can be regarded as a nitridated form of the oxide LaTiO3, in which a portion of the oxide O2− ions is replaced by nitride N3− to yield the formula LaTiO2N. The material is typically prepared by ammonolysis or ammonia-assisted high-temperature treatment of LaTiO3, which promotes incorporation of nitrogen into the lattice.

Structurally, LaTiO2N is related to the perovskite family and is described as a perovskite-like oxynitride. The titanium centers are coordinated by a mixed set of oxygen and nitrogen ligands, forming TiO and TiN–type environments within an octahedral framework. In many samples, oxygen and nitrogen are arranged in an ordered fashion, producing layered oxynitride motifs, although disordered variants also occur.

The incorporation of nitrogen into the lattice narrows the electronic band gap compared with the parent oxide, permitting absorption of visible light. The valence band is largely composed of nitrogen 2p states, while the conduction band has titanium 3d character. The material behaves as a semiconductor and is often used in conjunction with cocatalysts to enhance charge separation and surface reactions.

Applications for LaTiO2N focus primarily on photocatalysis under visible light. It has been explored for water splitting to produce hydrogen and for CO2 reduction, typically requiring co-catalysts such as platinum or other noble or earth-abundant metal sites to achieve practical activity. LaTiO2N serves as a model system for studying how anion ordering and mixed O/N compositions influence electronic structure and photocatalytic performance.

Challenges include improving overall efficiency, stabilizing the material under aqueous irradiation, and achieving precise control over anion ordering during synthesis. Ongoing research investigates doping, heterojunction strategies, and surface modifications to enhance activity and durability.