Synergistic effects of Fe and Ag doping on the structural and optical properties of a TiO2 thin film: a dual function platform for hydrogen generation and dye degradation

Abstract

The global population is increasing at an alarming pace, leading to a rapid surge in industrialization and concomitant environmental degradation. In light of the present circumstances, it is crucial to find sustainable solutions to mitigate pollution and ensure a safe and clean environment for the present and future society. One promising solution is photocatalysis, which utilizes solar energy to address environmental issues while providing a renewable and sustainable energy source. Herein, a TiO₂-based multi-layer thin film photocatalyst was developed, and its hydrogen generation and Rhodamine 6G dye degradation properties were analysed. As TiO₂ undergoes excitation in the UV region, in order to shift the absorbance towards the visible region, bandgap engineering was performed with Fe and Ag doping. As a consequence, the band gap effectively reduces, and Fe and Ag doping result in the least gap energies measuring 2.7 eV and 2.85 eV, respectively. DFT band structure study was performed, which shows the presence of additional electronic states that lie in the conduction and valence energy bands of TiO₂ owing to the doping of elements. Additionally, the effect of the number of thin film layers on photocatalysis was investigated. To confirm the presence of structural distortions and oxygen vacancies, different characterizations were performed.