Scalable production of ultra small TiO2 nano crystal/activated carbon composites by atomic layer deposition for efficient removal of organic pollutants

Abstract A high surface area photo-catalytic composite material is synthesized by depositing thin films of titanium dioxide (TiO2) on activated carbon (AC) particles using atomic layer deposition (ALD). A rotary ALD reactor is developed for scalable fabrication of powder and grams of the catalyst is prepared in each batch. The processes of TiO2 ALD are monitored by mass spectrometry. Saturated ALD surface reactions are confirmed so that the entire surface of the AC support is covered by conformal coatings of TiO2. For composites fabricated by 3 or more ALD cycles of TiO2, the amorphous oxide layers can be converted to crystalline films by high temperature annealing. The as-prepared TiO2/AC composites are highly reactive in photo-catalyzed degradation of methyl orange. The excellent catalytic performance is attributed to the abundant and uniformly dispersed active phase, formation of very active ultra small (