Nano-sized Ga2–xCuxZr2–xWxO7 for Malachite green decolorization under visible light

Novel nano-sized Ga 2–x Cu x Zr 2–x W x O 7 system was prepared using the Pechini method, where x = 0, 0.05, 0.1 and 0.015. A single cubic fluorite phase was detected for all the prepared samples. The lattice parameter and unit cell volume of the undoped Ga 2 Zr 2 O 7 is higher than that of Cu, W co-doped Ga 2 Zr 2 O 7 samples. The band gap was decreased from 4.95 eV for the undoped Ga 2 Zr 2 O 7 to 2.89 eV for Ga 1.85 Cu 0.15 Zr 1.85 W 0.15 O 7 sample (15 mole % Cu and 15 mole % W doped Ga 2 Zr 2 O 7 ), shifting the absorption edge to the visible light area. The photocatalytic degradation efficiency of Ga 2–x Cu x Zr 2– x W x O 7 system for malachite green dye as a water contaminant model was presented. The photocata- lytic activity of Ga 1.85 Cu 0.15 Zr 1.85 W 0.15 O 7 recorded 93.84% degradation of malachite green dye, which is higher than that of the undoped Ga 2 Zr 2 O 7 (16.66%). The photocatalytic degradation reaction for the malachite green dyes was inconsistent with the Pseudo-first-order kinetics model. The reusability of the prepared system as a catalyst was proven. The intermediates and the reaction pathways were detected by GC-MS.