Hierarchically-Structured TiO2/MnO2 Hollow Spheres Exhibiting the Complete Mineralization of Phenol

Abstract

Although TiO2 or MnO2-based materials have been widely used for the degradation of phenolic compounds, complete mineralization is still a challenge, especially for TiO2-based materials. Here, we devise a hierarchically-structured TiO2 /MnO2 (HTM) hollow sphere, in which hollow TiO2 acts as a skeleton for the deposition of MnO2 in order to prevent the aggregation of MnO2 nanoparticles and to maintain its hollow structure. During the oxidation reaction, the as-synthesized HTM can fully exert their respective advantages of the TiO2 and MnO2 species to realize the first stage of the rapid oxidation degradation of phenol and the second stage of the complete photo-mineralization of residual phenol and its intermediates, which efficiently overcomes the incomplete mineralization of phenolic compounds. The degradation mechanism and pathway of phenol are also proposed according to the analysis of Mass Spectrometry (MS). Therefore, this work provides a new insight for exploring hierarchically-structured materials with two or more species.