Metal organic framework-derived C-doped ZnO/TiO₂ nanocomposite catalysts for enhanced photodegradation of Rhodamine B

A series of C-doped ZnO/TiO₂ composites with various molar ratios of ZnO to TiO₂ were synthesized by one-step controllable pyrolysis of Zn/Ti bimetallic metal-organic frameworks (Zn/Ti-MOF). The Zn/Ti-MOF was prepared using a facile microwave hydrothermal method. Electron microscopic analysis proved that the composites presented regularity cubic morphology with an edge length of about 1 μm and the C atoms were successfully doped into ZnO/TiO₂ composites. X-ray photoelectron spectroscopy (XPS) measurement results confirmed the C-doping in the ZnO/TiO_2. Comparative experimental studies showed that 2% ZnO/TiO₂ composites prepared with the calcination temperature of 600℃ displayed the best photocatalytic degradation efficiency (94%) of RhB under the simulated sunlight irradiation. Cyclical experiment indicated the high stability and reusability of 2% ZnO/TiO₂ composites. Electron spin resonance (ESR) and trapping experiments illustrated that the produced ^[rad]O₂⁻ served as the main active species for the efficient RhB removal. This work provides an efficient way for preparing C-doped bimetal oxides composites, which would have an important application prospect in the photocatalytic degradation of organic pollutants in environmental water.