Cobalt implanted TiO2 nanocatalyst for heterogeneous activation of peroxymonosulfate

Abstract

In the past decades, catalyst stability and metal ions leaching have always been one of the most important issues in the heterogeneous peroxymonosulfate (PMS) activation system. In this work, cobalt implanted TiO₂ was proposed as an effective catalyst for improving the catalyst stability and inhibiting cobalt leaching. A simple hydrolysis method was employed for the preparation of nanocatalysts with Co(NO₃)₂·6H₂O and Ti(OC₃H₇)₄ as precursors. Characterization by X-ray diffractometry, X-ray photoelectron spectroscopy and temperature programmed reduction indicated that the doped cobalt uniformly distributed in the faces of TiO₂ crystallite as Co²⁺ and interacted with TiO₂ through a strong Co–O–Ti bond. Compared to the Co₃O₄ immobilized TiO₂ catalysts, the cobalt ion implanted TiO₂ nanocatalysts reduced half of the cobalt dosage but exhibited paralleled catalytic activity and, moreover, the cobalt leaching declined about 60%. The reduction of cobalt dosage, uniform distribution of Co²⁺ in the TiO₂ crystal lattice and the strong interaction of Co²⁺ with TiO₂ support were believed to improve the performance in heterogeneous activation of peroxymonosulfate (PMS) and decrease the cobalt leaching.