Amorphous TiO2 as a Photocatalyst for Hydrogen Production: A DFT Study of Structural and Electronic Properties

Abstract

In recent years, photocatalytic splitting of water to produce hydrogen has attracted significant attention. Crystalline forms of titanium dioxide (TiO2) have been investigated for decades. Amorphous TiO2, although less expensive, has not been studied as thoroughly. This study investigates the structural and electronic properties of amorphous TiO2. Molecular dynamics simulations are used to prepare multiple amorphous TiO2 samples having different number of atoms. The structural analysis agrees well with the experimental data. Electronic properties of amorphous TiO2 are investigated through density functional theory calculations. Band gap characteristics of amorphous TiO2 are compared with experimental data for amorphous as well as crystalline (rutile and anatase) TiO2 phases. Analysis of electronic properties suggests that amorphous TiO2 may prove as a cheaper, more abundant, but somewhat less efficient photocatalyst as compared to crystalline TiO2.