Photocatalytic Efficiency Assessment of Powders

The photocatalytic effectiveness of the obtained powders and composites upon visible-light exposure was assessed by employing 0.005 g of each product in RhB aqueous solution (0.01 M, 5 mL) at ambient temperature and pH = 7.50 ± 0.01, under constant stirring. Before each photocatalytic trial, pure oxygen (99.999%) was vented via RhB’s solution for 2 h in the absence of light to ensure saturation. The photoreactor utilized featured four parallel lamps positioned 10 cm above each sample’s surface. These lamps were 15 W daylight lamps (350–750 nm, 3 mW/cm², OSRAM GmbH, Munich, Germany). The as-synthesized samples’ absorbance was quantified utilizing a Hitachi U-2001 Spectrophotometer (Hitachi, Tokyo, Japan). The assessment involved determining the fraction of the assessed absorption (A) at each specific time point to the initial absorption (A_initial) after the nanoparticles had been removed by centrifugation, thereby enabling the concentration fraction’s (C/C₀) calculation, where C represents RhB’s concentration after a specific duration of photocatalytic trials, and C₀ corresponds to RhB’s initial concentration measured at λ = 554 nm [32 (link)].