Synthesis and photocatalytic activities of Cu(Ⅱ) complex micro-crystals derived from trizole-pyridyl carboxylic acid

Micro-crystals of complex Cu₂(tpa)₂(OH)_n were prepared using CuCl₂∙2H₂O and trizole-pyridyl carboxylic acid (Htpa) as raw material in DMF/methanol solvent by a solvent volatilization method. The synthesized Cu(Ⅱ) complex micro-crystals were characterized by infrared spectroscopy, scanning electron microscope, X-ray powder diffraction and UV-Vis diffuse reflection spectroscopy. The photocatalytic system consisting of Cu₂(tpa)₂(OH)_n and H₂O₂ was used to degrade the alkaline fuchsin and rhodamine B dyes under visible light, and the degradation process of alkaline fuchsin and rhodamine B was simulated by kinetic models. The results showed that Cu₂(tpa)₂(OH)_n/H₂O₂ catalytic system exhibited good photocatalytic activities for the degradation of alkaline fuchsin and rhodamine B dyes. The degradation efficiency of alkaline fuchsin was up to 84.0% after reacting for 90 min, while the degradation efficiency of rhodamine B was up to 96.3% after reacting for 25 min. The reaction kinetic study suggested that the photodegradation processes of alkaline fuchsin and rhodamine B were in accordance with the pseudo-first-order kinetic model. The rate constants (k) of alkaline fuchsin and rhodamine B are 2.030 × 10⁻² min⁻¹ and 1.246 × 10⁻¹ min⁻¹, respectively. Finally, the mechanism of photocatalytic degradation of organic dyes by Cu₂(tpa)₂(OH)_n/H₂O₂ system was discussed.