Synthesis Of Hectorite-tio_2 And Kaolinite-tio_2 Nanocomposites With Photocatalytic Activity For The Degradation Of Model Air Pollutants

摘要

We studied the synthesis and photocatalytic activity of small-sized TiO_2 supported on hectorite and kaolinite. Deposition of TiO_2 on the clay mineral surface was conducted by using a sol-gel method with titanium isopropoxide as precursor. Anatase TiO_2 particles formation was achieved by hydrothermal treatment at 180 ℃. Material characterization was conducted using XRD, SEM, XPS, ICP-OES, BET and porosimetry analysis, fficiency in synthesizing clay-TiO_2 composites depended strongly on the clay mineral structure. Incorporation of anatase in hectorite, an expandable clay mineral, was found to be very significant (>36 wt.% Ti) and to be followed by important structural changes at the clay mineral surface. Instead, no major structural modifications of the clay were observed for kaolinite-TiO_2, as compared with the untreated material. Photocatalytic performance of clay-TiO_2 composites was evaluated with ATR-FTIR following the oxidation of adsorbed toluene and D-limonene, two model air pollutants. In either case, the photocatalytic removal efficiency of these hydrophobic substrates by the synthesized clay-TiO_2 composites was comparable to that observed using pure commercial TiO_2 (Degussa P25).