Layer-by-layer assembly of TiO₂nanowire/carbon nanotube films and characterization of their photocatalytic activity

Abstract

We report on the layer-by-layer (LbL) formation of TiO(2)-MWNT-TiO(2) coatings on quartz with either trititanate derived TiO(2) nanowires or Degussa P25 as the photocatalytically active material. The optimized deposition sequence is discussed in detail and the morphology of the prepared coatings is analyzed by SEM and XRD. The heterogeneous photocatalytic performance of the coatings was tested in the methyl orange oxidation reaction. The apparent first order rate constant fell in the 0.01-0.20 h(-1) range over a 2.5 × 2.5 cm(2) film depending on the type and the thickness of the titanate coating. Building a multiwall carbon nanotube layer into the middle of the layer improved the photocatalytic activity for each material for all of the studied thicknesses. P25 based films performed 2-5 times better than TiO(2) nanowire films; however, the pores in the P25 based films were largely blocked because the isotropic P25 nanoparticles form closely packed layers by themselves and even more so with the comparably sized multiwall carbon nanotubes. Therefore, films derived from titanate nanowires appear to be more suitable for use as multifunctional, photocatalytically active filtration media.

Optical visualization of individual ultralong carbon nanotubes by chemical vapour deposition of titanium dioxide nanoparticles

“…Although a series of covalent and non-covalent methods have been reported to deposit metal [26][27][28][29][30] or metal oxide NPs [19][20][21][22][23][24][25][30][31][32][33][34][35][36][37][38][39][40][41][42] on CNTs, most of these methods require the CNTs to be functionalized or modified with surfactants 39,42 , and the processes are conducted in liquid phases 41,42 . These strategies cannot be applied on individual suspended ultralong CNTs because of the fact that they will destroy the suspended CNTs.…”

Sieve-Like CNT Film Coupled with TiO2 Nanowire for High-Performance Continuous-Flow Photodegradation of Rhodamine B under Visible Light Irradiation

“…8 μm were manufactured by the FCCVD method [ 18 , 35 ]. TiO 2 nanowires were coupled facilely onto porous CNT films via a hydrothermal strategy as reported in previous works [ 36 , 37 ]. Specifically, the pristine CNT films were cut into identical circles (Ø 5.5 cm) and then engraved by laser drilling.…”

Electrochemical nanoarchitectonics and layer-by-layer assembly: From basics to future

“…During the last decade, water evolution reactions induced by photocatalysis or electrocatalysis have attracted great interest from the research community since it could be used to develop replacement technologies for non-renewable energy sources [226][227][228][229]. Surprisingly, very few attempts have been made to achieve water splitting using the LbL platform although they have been frequently used for triggering other reactions [230,231]. In 2013, the group of Zhao reported LbL assembly of Co 3 O 4 NPs/graphene composites [232] with the resulting films exhibiting better physical stabilities and catalytic activities than the pristine catalysts both for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR).…”