In conclusion, DRS is a valuable tool for analyzing the band gap of doped Titanium dioxide photocatalysts. By understanding the relationship between dopant concentration and band gap energy, researchers can design photocatalysts with optimized properties for specific applications, such as water splitting, CO2 reduction, or organic pollutant degradation. The ability to harness visible light more effectively can lead to the development of more sustainable and efficient photocatalytic systems for energy and environmental applications.