Comparison between thermal and plasma-enhanced atomic layer deposition of ZnO on fullerene powder for photocatalytic dye removal

ZnO was deposited on fullerene C60 by Atomic Layer Deposition (ALD), carried out in thermal (t-ALD) and Plasma Enhanced (PE-ALD) mode. The ALD technique allowed to grow stoichiometric and crystalline ZnO, in increasing amount with the number of cycles. The conformal deposition was successful not only on the surface but even on the walls of the pores of the material: t-ALD enabled the coverage of both superficial and deeper pores, whereas, in the case of PE-ALD, ZnO was found mainly on the walls of the most superficial ones. The photocatalytic activity of the ZnO@C60 nanocomposites obtained at 400 cycles by thermal and PE-ALD was evaluated through monitoring the discoloration of a 1.0 & sdot;10-5 M methylene blue solution upon UV irradiation (lambda=254 nm) over 180 min. Results indicate that the photocatalytic performance of the t-ALD coated C60 was higher than the one obtained by PE-ALD (54 % vs 33 %, respectively), in accordance with the higher amount of ZnO on the t-ALD treated samples.