Three-Dimensional Carbon Nanotube Scaffolds as Particulate Filters and Catalyst Support Membranes

Abstract

Three-dimensional carbon nanotube scaffolds created using micromachined Si/SiO₂ templates are used as nanoparticulate filters and support membranes for gas-phase heterogeneous catalysis. The filtering efficiency of better than 99% is shown for the scaffolds in filtering submicrometer particles from air. In the hydrogenation of propene to propane reaction low activation energy of E_a ∼27.8 ± 0.6 kJ·mol⁻¹, a considerably high turnover rate of ∼1.1 molecules·Pd site⁻¹·s⁻¹ and durable activity for the reaction are observed with Pd decorated membranes. It is demonstrated that appropriate engineering of macroscopic-ordered nanotube architectures can lead to multifunctional applications.