Methylene blue photodegradation employing hexagonal prism-shaped niobium oxide as heterogeneous catalyst: Effect of catalyst dosage, dye concentration, and radiation source

Highlights: • Nb-based catalysts were prepared using Nb scrap and chips as precursors. • The feasibility of using Nb-based catalysts for the degradation of MB was studied. • Niobic acid and niobium oxide showed great performance in the degradation process. • The highest degradation efficiency is reached using UVC radiation. • The amount of acid sites, adsorbed H₂O and OH⁻ groups are important for the process.