2016 AIChE Annual Meeting
(340h) Preparation and Photocatalytic Properties of g-C3N4/TiO2/BiVO4
Preparation
and Photocatalytic Properties
of g-C3N4/TiO2/BiVO4
Shen Xinlin, Wang Youliang, Li Kebin, Wang Fengyun
The Institute of Industrial Chemistry,
Nanjing University of Science & Technology, Nanjing 210094, P.R.China
Keyword: g-C3N4/TiO2/BiVO4; preparation; MB degradation
Over
the last few decades, the semiconductor-based photocatalysis has emerged as an
environmentally benign technology for wastewater treatment due to its
destructive ability towards a wide range of inorganic and organic pollutants[1-3]
. TiO2 is by far the most commonly being researched photocatalytic
material owing to its many advantages for photocatalytic applications, e.g.
high redox potentials, long-term thermodynamic stability, cost-effective and
non-toxicity[1,4,5]. Whereas the bare TiO2 suffers from
several disadvantages including the limit to ultraviolet (UV) light absorption
due to its wide band gap, as well as low quantum efficiency resulting from the
rapid recombination of photogenerated electron¨Chole pairs. To overcome these
drawbacks and enhance the photocatalytic activity of TiO2, we constructed
and prepared a ternary catalyst, i.e., mpg-C3N4/TiO2/BiVO4.
The mpg-C3N4
was obtained in a typical synthesis: dicyandiamide was used as raw
material and SBA-15 as template agent and calcined under nitrogen atmospheres. The
binary and ternary catalysts were prepared by hydrothermal.
The
XRD patterns of catalysts are shown in Figure 1. There are two peaks found in
mpg-C3N4 sample at 12.28¡ãand 27.51¡ã, which can be indexed
to (100) and (002) peak. The peaks at 25.5¡ã (101), 38.2¡ã (004), 48.2¡ã (200) and 54.9¡ã (105)
indicate the existence of anatase TiO2 phase (JCPDS No. 21-1272).
The other diffraction peaks
are agreement with monoclinic BiVO4 phase (JCPDS No. 14-0688).
No characteristic
diffraction peaks of mpg-C3N4 can be observed for the
ternary composite because of its low content and poor crystallization. But,
its existence can be
evidenced by FTIR spectra in figure 2. We have prepared the ternary mpg-C3N4/
BiVO4/TiO2 composite successfully.
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Figure 1 : XRD patterns of mpg-C3N4; BiVO4; TiO2; BiVO4/TiO2; mpg-C3N4/ BiVO4/TiO2 |
Figure 2 : FTIR spectra of mpg-C3N4; BiVO4/TiO2;mpg-C3N4/ BiVO4/TiO2 |
The TEM images of catalysts are shown in
figure 3, we can see the binary and ternary catalysts are the
formation of heterojunction. Although the size of the structure reach micron
grade, the minimum structure of the hierarchical structure unit is still the
nanoscale.
The effect of photocatalytic degradation for
methylene blue (MB) under visible light radiation (¦Ë ¡Ý 420 nm) is shown in figure 4. It shows that the methylene blue is almost completely
degraded by the ternary mpg-C3N4/ BiVO4/TiO2
composite after 2 h. It proves that the mpg-C3N4/ BiVO4/TiO2
composite is more efficiently than the binary and pure catalysts.
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Figure 3 : The TEM image of catalysts : (a) mpg-C3N4 ; (b) TiO2 ; (c) BiVO4 ; (d-e)BiVO4/TiO2 ; (f)mpg-C3N4/ BiVO4/TiO2 |
Figure 4 : The effect of photocatalytic degradation of methylene blue under visible radiation (¦Ë ¡Ý 420 nm) |
The ternary
mpg-C3N4/BiVO4/TiO2 catalysts have
been prepared by calcination-
hydrothermal successfully. It has been comfirmed of the formation of
heterojunction by XRD, FTIR and TEM. The titled photocatalyst is efficiency for degradation of methylene blue
under visible light radiation (¦Ë ¡Ý 420 nm).
References