Ti3+ Self-Doped Tio2 Nanoparticles Immobilized on Self-Pillared Pentasil Zeolite Nanosheets: An Efficient Visible-Light-Driven Photodegradation Catalyst

Abstract

Ti3+ defective TiO2 nanoparticles (TiO2-N) were synthesized through slow hydrolyzation of tetrabutyl titanate and low-temperature annealing, followed by loading on self-pillared pentasil (SPP) zeolite nanosheets to construct a TiO2/zeolite hybrid composite by solid-state dispersion. The obtained TiO2-N/SPP composite exhibited a distinct red-shift in the UV-vis absorption spectrum and a significantly reduced band gap due to the introduced Ti3+ defects and the consequent oxygen vacancies (VO), leading to an enhanced visible-light responsivity. The diverse porosity and house-of-cards nanosheet morphology of the SPP support not only promoted the efficient loading and stable immobilization of TiO2-N nanoparicles through micropore migration and surface adhesion but also endowed the adsorbability to the TiO2-N/SPP composite. The adsorptive photodegradation of methylene blue (MB) was used to evaluated the photocatalytic performance of TiO2-N/SPP, and a 95.6% degradation rate of MB was observed after 3 h illumination with visible-light. The adsorptive effect strongly promoted the accessibility of MB molecules to the active TiO2 species, leading to a remarkable enhancement in degradation efficiency. Moreover, a superior recyclability embodied in the retention of 96.4% photocatalytic activity after three regeneration cycles indicated the TiO2-N/SPP composite to be practical for water pollutant degradation.

Keywords: TiO2/zeolite composite, Ti3+ defect, Oxygen vacancy, SPP, Photodegradation