(69h) One-Step Deposition of Photocatalytically Active TiO2 Films Via Wire-to-Plate Dielectric Barrier Discharge Plasma at Atmospheric Pressure

One-step deposition of photocatalytically
active TiO₂ films via wire-to-plate dielectric barrier discharge plasma
at atmospheric pressure

Lan-Bo
Di, Xiao-Song Li and Ai-Min Zhu^*

Laboratory of Plasma
Physical Chemistry,
Dalian University of Technology, Dalian 116024,
China

^*Corresponding author. E-mail: amzhu@dlut.edu.cn

 
TiO₂ films play an important role in extensive applications such
as photocatalysis, photovoltaics,
biocompatibility, and sanitary disinfection ^{[1, 2]}. Low-temperature
film fabrication processes are essential for all thermally sensitive or unstable
substrate materials such as organic polymers and textiles. Plasma CVD is highly
suitable for low-temperature fabrication, but it has mainly been low pressure
incorporated with sophisticated discharge and vacuum systems that have been
adopted. ^[3¨C5] Thus, in recent years, considerable attention has
been paid to the development of atmospheric-pressure, non-thermal plasma CVD
technologies ^[6].

Dielectric barrier discharge (DBD) was widely used for
generating atmospheric pressure, non-thermal plasmas and recently explored for
preparing TiO₂nanopowders or films ^[7-18].
In this paper, wire-to-plate DBD induced plasma CVD device, as illustrated in figure 1, was
employed to fabricate photocatalytically active TiO₂
films on moving glass or plastic substrates at atmospheric pressure. The
discharge gap has an adjustable distance from 0.3 mm to 0.6 mm.

Figure 1. Schematic of
the wire-to-plate DBD induced plasma CVD device for TiO₂ film
fabrication. 1¨CAr + TiCl₄, 2¨Cdry air, 3¨Calumina
tube, 4¨Cdischarge electrode, 5¨C moving substrate, 6¨Cdielectric, 7¨Cground
electrode.

TiCl₄vapour, as the Ti precursor, was carried by Ar gas from a bubbler placed in an ice-water bath, mixed with
Ar diluting gas and then flowed
into the discharge area. Dry air was used as the oxygen precursor.

The photocatalytic reaction
test for TiO₂ films was performed by complete oxidation of HCHO in
simulated air with a continuous flow reactor under UV irradiation of a 254 nm
lamp (8 W) ^[11].

The as-deposited TiO₂
films on cover glass or plastic substrates, prepared at 1 L°¤min^-1 total flow rate, 27 W input
power, 0.3 mm discharge gap, and
29 Pa TiCl₄ partial pressure, exhibited high photocatalytic
activity. The apparent rate constants of the TiO₂ films on cover
glass and plastic substrates are 0.99
s^-1 and 0.52 s^-1,
respectively.

The influence of input power,
discharge gap and the partial pressure of TiCl₄ on the photocatalytic activity of the as-deposited TiO₂
films were also investigated.

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