Fig. 1. Schematic picture of OP preparation.Figure optionsDownload full-size imageDownload as PowerPoint slide
2.4. Preparation of NdT/OP catalyst
OP nanoparticles (0.4 g) were dissolved under magnetic stirring in 25 mL of HCl (0.85 mol L−1) aqueous solution. First TEOS (2 mL), and then NdT (0.12 g) were added to SM-164 solution (Fig 2). The mixture was kept under stirring for 48 h at 25 °C and then centrifuged to recover the final NdT/OP solid phasee. The nominal loading of NdT in the catalyst was 30 wt% .
Fig. 2. Schematic picture of NdT/OP preparation.Figure optionsDownload full-size imageDownload as PowerPoint slide
2.5. Samples characterization
The samples were characterized with several techniques. Specific surface area of catalysts were obtained by N2 adsorption measurement at −196 °C with a Costech Sorptometer 1040 after pretreatment at 60 °C for 120 min in He flow (99.9990%). UV–vis reflectance spectra were recorded with a PerkinElmer spectrometer Lambda 35. The TiO2 content of the NdT/OP sample was determined by X-ray fluorescence spectrometry (XRF) in a thermoFischer ARL QUANT\'X EDXRF spectrometer equipped with a rhodium standard tube as the source of radiation and with Si–Li drifted crystal detector. X-ray diffraction (XRD) was carried out using an X-ray microdiffractometer Rigaku D-max-RAPID (Cu-Kα radiation). Raman spectra were obtained at room temperature with a Dispersive MicroRaman spectrophotometer (Invia, Renishaw), equipped with a 514 nm diode-laser, in the range 100–2500 cm−1.