Determining anisotropic reactive facet of ilmenite photocatalyst with Hubbard U assisted density functional theory

Abstract

Findings on favorable charge-transfer pathways have been challenged for the enhancing catalytic reaction because electrical and optical efficiency are influenced by the interfacial/surface environment on the crystal structure. Herein, the electric and optical peculiarities of ATiO3 ilmenite catalyst are investigated for the anisotropic charge pathways by density functional theory framework with Hubbard U (DFT + U). The uncertainty for the best Hubbard U is simulated for the lattice parameters and band gaps in ATiO3. Our simulation corrected by Hubbard U = 10 eV shows the best reliability for ATiO3 involving 30 atoms as a basis at constant ilmenite structure and concluded that Perdew-Burke-Ernzerhof functional performance overcomes the deficiency of standard local density approximation functionals. Anisotropic carrier mobility in the Brillouin zone is compared with DFT + U on A-site cation effects. Among the representative three kinds of cations, our result shows that NiTiO3 exhibits a good optical absorption performance with the dielectric function and absorption coefficient in the visible light range, especially along the b3 direction which facilitates the separation of photogenerated electron-hole pairs at the top side of the shape. Our computational approach suggests a high reactive crystal facet of transition metal oxide contributing to the viable approach for the efficient catalytic reaction.