TiN anchored mesoporous single-crystalline LaTiO2N with ohmic contact to expedite photocarrier separation for efficient photocatalytic water splitting

LaTiO2N is a promising photocatalyst for solar water splitting but is generally subject to a low activity due to inadequate separation of photocarriers (i.e. e(-) and h(+)). Loading noble metal cocatalysts such as Pt often has limited improvements because of their Schottky-type interfaces with LaTiO2N, resulting in a deficient electron collection at the surface catalytic sites. In this work, TiN nanoparticles have been firmly anchored at the surface of mesoporous single-crystalline LaTiO2N. As opposed to Pt, TiN has an ohmic contact with LaTiO2N due to a comparable work function and the structurally matched heterointerfaces. Such a tight and ohmic connection enables TiN to readily collect electrons from LaTiO2N, which in turn substantially improves the photocarrier separation and photocatalytic activity. These findings justify that TiN is an ideal relay for electron transfer between n-type semiconductors and noble metal cocatalysts which would otherwise be very difficult when the Schottky-type interfaces are formed.