Mechanistic investigation of RhB photodegradation under low power visible LEDs using a Pd-modified TiO2/Bi2O3 photocatalyst: Experimental and DFT studies

An energy efficient hydrothermal route has been adopted for the synthesis of binary TiO2/Bi2O3, followed by a chemical method to prepare a series of novel ternary TiO2/Bi2O3/Pd nanocomposites. The characteristics of the resulting composites were uncovered using advanced techniques. The results revealed the formation of the desired products with improved characteristics. Among the binary and ternary samples, TiO2/Bi2O3 (15%) and TiO2/Bi2O3 (15%)/Pd (3%) showed the best activity toward the degradation of RhB under irradiation with visible LEDs. After cyclic experiments, no significant decrease in the efficiency was detected. The degradation pathway of RhB was uncovered using density functional theory (DFT) and mass spectroscopy. From scavenger studies, superoxide anion radical and holes were found the prominent active species responsible for the removal of RhB. The as-synthesized composites are useful for the fabrication of low power consuming photoreactors for use in efficient water purification systems.