# Thermally Activated Composite Y2O3-bTiO2 as an Efficient Photocatalyst for Degradation of Azo Dye Reactive Black 5

## TL;DR

A new low-cost composite material efficiently degrades a harmful textile dye under sunlight, offering a sustainable solution for water pollution.

## Contribution

A cost-effective and simple method to synthesize Y2O3-bTiO2 composite for enhanced photocatalytic dye degradation.

## Key findings

- Y2O3-bTiO2 achieved complete RB5 degradation in 60 min under simulated sunlight.
- The composite showed pseudo-first-order kinetics with a rate constant of 0.064 min−1.
- Depositing Y2O3 reduced electron–hole recombination and improved quantum yields.

## Abstract

Water pollution from textile effluents poses serious environmental risks, particularly due to persistent anionic dyes such as Reactive Black 5 (RB5). This study demonstrates that simple deposition of Y2O3 onto commercially available, biobased TiO2 (bTiO2) significantly enhances photocatalytic degradation efficiency under simulated sunlight, suppressing rapid recombination of electron–hole pairs. Addressing a key research gap, the proposed method replaces expensive nanoscale precursors and complex synthesis routes typically used for Y2O3/TiO2 systems with a low-cost, straightforward approach involving weak complexation and co-precipitation. The resulting Y2O3-bTiO2 composite was characterized using FTIR, XRD, SEM, EDX, TEM, XPS, and UV-DRS techniques, confirming efficient incorporation of Y2O3 on the TiO2 surface. Photocatalytic experiments revealed that nanoparticles calcined at 700 °C achieved complete RB5 degradation within 60 min—reducing the reaction time by half compared to undoped bTiO2. Systematic studies of initial dye concentration, catalyst loading, and irradiation time confirmed that the degradation followed pseudo-first-order kinetics with a rate constant of 0.064 min−1 (R2 = 0.98). Calculated quantum yields corroborated the reduced electron–hole recombination induced by Y2O3 deposition. These findings highlight the novelty and practicality of the developed Y2O3-bTiO2 photocatalyst as an efficient, affordable, and environmentally sustainable material for the degradation of industrial dyes.