Alumina coating with TiO 2 and its effect on catalytic photodegradation of phenol and p ‐cresol

BACKGROUND This study is focused on the peptization of Boehmite and titanium alkoxide (modified sol–gel method) to obtain Al 2 O 3 –TiO 2 mixed oxides taking advantage of the physicochemical properties of TiO 2 and Al 2 O 3 . TiO 2 is an important semiconductor and the most active photocatalyst. Al 2 O 3 is an insulator with high surface area and thermal, chemical and mechanical resistance. It is possible to produce high surface area materials, where TiO 2 is dispersed on the alumina surface for photodegradation of pollutants. RESULTS γ‐Al 2 O 3 –TiO 2 (5, 10 and 15 wt% TiO 2 ) mixed oxides presented stabilization of the anatase phase. Rietveld studies showed incorporation of the Al 3+ into the TiO 2 anatase and Ti 4+ into the Al 2 O 3 . They exhibit higher specific surface area than pure TiO 2 . The TiO 2 ‐coated alumina surface with small TiO 2 particles produced a large number of active sites on the surface. The sample with 15 wt% of TiO 2 presented the highest photodegradation of p ‐cresol and phenol. CONCLUSION The addition of TiO 2 to the alumina improved the photoactivity of pure TiO 2 producing materials with higher surface area covered with TiO 2 . Alumina delayed the recombination of photogenerated electron–hole pairs favoring the formation of highly reactive •OH radicals. The photodegradation of p ‐cresol and phenols increased with TiO 2 loading increase. © 2016 Society of Chemical Industry