Modulating Optoelectronic and Elastic Properties of Anatase TiO(2) for Photoelectrochemical Water Splitting

Titanium dioxide (TiO(2)) has been investigated for solar-energy-driven photoelectrical water splitting due to its suitable band gap, abundance, cost savings, environmental friendliness, and chemical stability. However, its poor conductivity, weak light absorption, and large indirect bandgap (3.2 eV) has limited its application in water splitting. In this study, we precisely targeted these limitations using first-principle techniques. TiO(2) only absorbs near-ultraviolet radiation; therefore, the substitution (2.1%) of Ag, Fe, and Co in TiO(2) significantly altered its physical properties and shifted the bandgap from the ultraviolet to the visible region. Cobalt (Co) substitution in TiO(2) resulted in high absorption and photoconductivity and a low bandgap energy suitable for the reduction in water without the need for external energy. The calculated elastic properties of Co-doped TiO(2) indicate the ductile nature of the material with a strong average bond strength. Co-doped TiO(2) exhibited fewer microcracks with a mechanically stable composition.