Influence of crystallite structure of nanometer TiO2 catalysts on photocatalyst reaction

25 samples of nanometer TiO₂ were prepared through modifying the preparation conditions including the concentrations of Ti(SO₄)₂ and NH₄HCO₃, the pH value at the end of precipitation operation, and sintering temperature and time by methods of orthogonal design. The relationships between their catalytic activities of photocatalytic degradation of sodium dodecyl benzene sulfonate (SDBS) and the normal crystallite size, lattice-strain and X-ray diffraction intensity of 10 crystal faces were analyzed. It was discovered that the photocatalytic degradation reaction of SDBS follows first-order kinetics. Crystal faces of catalysts’ (101) have greater influence than other crystal faces on the reaction. The photocatalytic reaction needs more perfect (101) crystal faces with less lattice-strain. Smaller normal crystallite size and greater specific surface area of (101) crystal face are better for increasing reaction rate. The photocatalytic reaction is mainly proceeded on the (101) crystal face, comparatively, amorphous TiO₂ has lower catalytic activity.