Synthesis of Pt@TiO(2)@CNTs Hierarchical Structure Catalyst by Atomic Layer Deposition and Their Photocatalytic and Photoelectrochemical Activity

Pt@TiO(2)@CNTs hierarchical structures were prepared by first functionalizing carbon nanotubes (CNTs) with nitric acid at 140 °C. Coating of TiO(2) particles on the CNTs at 300 °C was then conducted by atomic layer deposition (ALD). After the TiO(2)@CNTs structure was fabricated, Pt particles were deposited on the TiO(2) surface as co-catalyst by plasma-enhanced ALD. The saturated deposition rates of TiO(2) on a-CNTs were 1.5 Å/cycle and 0.4 Å/cycle for substrate-enhanced process and linear process, respectively. The saturated deposition rate of Pt on TiO(2) was 0.39 Å/cycle. The photocatalytic activities of Pt@TiO(2)@CNTs hierarchical structures were higher than those without Pt co-catalyst. The particle size of Pt on TiO(2)@CNTs was a key factor to determine the efficiency of methylene blue (MB) degradation. The Pt@TiO(2)@CNTs of 2.41 ± 0.27 nm exhibited the best efficiency of MB degradation.