Fabrication of Pt doped TiO-ZnO@ZIF-8 core@shell photocatalyst with enhanced activity for phenol degradation.

Phenol's presence in aqueous solution due to the pollution from chemical and agricultural industries (e.g., coking tobacco leaves) causes severe environmental problems. As a result, many scientists and engineers search for catalysts to remove phenol from water by photodegradation. Thus, we synthesized Pt-doped TiO-ZnO@ZIF-8 core@shell particles (Pt/TiO-ZnO@ZIF-8) by a simple method involving crystallization, absorption, pyrolysis and growth steps. The resulting materials were analyzed by the powder X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM, respectively), surface area measurements and UV-vis absorption spectroscopy. The photocatalytic activities of our materials were evaluated by phenol degradation in aqueous solutions. Pt-doped TiO-ZnO particles possessed a polyhedral structure and exhibited broad absorption above 400 nm. Coating with ZIF-8 increased the specific surface area of the Pt-doped TiO-ZnO particles. Both Pt doping and ZIF-8 coating significantly enhanced the photocatalytic performance of TiO-ZnO. Pt/TiO-ZnO@ZIF-8 decomposed 99.7 % of phenol after the corresponding solution was exposed to UV light for 24 min. This performance was significantly better than the phenol decomposition ability of TiO-ZnO, Pt/TiO-ZnO and TiO, which degraded 76.1 %, 95.2 % and 86.9 % of phenol, respectively. Pt/TiO-ZnO@ZIF-8 also demonstrated excellent recycling stability. All these properties, including photostability, made our novel Pt/TiO-ZnO@ZIF-8 catalyst a promising material for practical applications in environmental remediation.