Mixed-phase of mesoporous titania nanoparticles as visible-light driven photodegradation of 2-chlorophenol: influence type of surfactant

Mesoporous titania nanoparticles (MTN) were prepared using different surfactants namely anionic (MTN-A), cationic (MTN-C) and nonionic (MTN-NI) surfactants via microwave-assisted method to degrade 2-chlorophenol (2-CP) under visible light irradiation. The catalysts were characterised by XRD, FTIR, UV-Vis DRS, PL, BET, FESEM, TEM and XPS. The mesoporous structures were successfully formed in all catalysts with high surface area. However, the significant difference between the prepared catalysts was the formation of mixed-phase in MTN-A which used sodium dodecyl sulfate (SDS) as anionic surfactant. MTN-A composed of 20% rutile and 80% anatase phase. MTN-A showed remarkable photoactivity due to the abundance of Ti3+ site defects (TSD) and oxygen vacancies (OV) on its TiO2 mixed-phase structures. The synergistic effect between the TSD, OV and TiO2 mixed-phase have improved the electronic band structure, aided the charge migration and reduced the electron–hole recombination rate, thus increasing its photoactivity. Moreover, MTN-A exhibited the best performance with 85% degradation compared to MTN-C, MTN-NI and pretreated commercial TiO2, Degussa P25 (P25) with 77%, 18% and 62% degradation, respectively. MTN-A also displayed as a promising photocatalyst because it could degrade other chlorophenol derivatives.