The hydrogenated black Ni–TiO2 nanoparticles exhibit a much greater efficiency in water splitting producing H2 gas over those of non-hydrogenated TiO2 and Ni-doped TiO2.
Anisotropy in non-metal doped TiO2: p-type dopants (S and Se) are optically active only for light polarized along the xy direction, and n-type dopants (N and C) are optically active along the xy as well as z directions.