responsive carbon material, in the TiO2, photocatalytic activity has been greatly
improved.
When the excellent performance of graphene was found, such as high surface
area, excellent mechanical property, outstanding electronic conductivity, special
photoelectrochemical property, and controllable bandgap [31–34], graphene as a
superstar in the material science has attracted much more attention in the past several
years. These properties determine its large potential for applications in electrochemistry and photocatalysis. Moreover, graphene can also potentially act as a support
material, which allows semiconductor particles such as TiO 2 to anchor on its surface.
Recently, the application of graphene in the electrochemical modification on TiO 2
has become a hot spot in the field of photocatalysis [35–40]. The compounding
between graphene and TiO 2 makes the successful connection between nanometer
modules with excellent properties, which greatly improves the transmission efficiency of optical carriers. Undoubtedly, the design and preparation of a series of new
types of efficient TiO 2 /graphene photocatalysts with excellent performance are the
new focus in the photocatalysis.
5.2 TiO 2 /Graphene Composite
5.2.1 Two-Dimensional TiO 2 /Graphene Composites
In 2009, the TiO 2 /graphene was firstly used in the photocatalysis for the
photodegradation of methylene blue (MB) reported by Li and his coworkers
[41]. They successfully synthesized a chemically bonded TiO 2 –graphene composite
with 2D graphene and nanosized P25. The as-prepared TiO 2 /graphene photocatalyst
exhibited extended light absorption range, excellent adsorption of MB, and efficient
photocatalytic activity. From then on, many researchers have reported many kinds of
TiO 2 /graphene composites by using different methods and used them in the
photocatalysis for the degradation of organic pollutants, water splitting, and CO 2
photoreduction. Here, we will discuss the preparation methods, the characterization
methods, and the applications of TiO 2 /graphene in photocatalysis.
5.2.1.1 Preparations
Since the TiO 2 /graphene composite was discovered by the researchers, the
2D-structured TiO 2 /graphene with various morphologies could be synthesized by
different methods, such as hydrothermal, mechanical mixing, pyrolysis, sol–gel,
CVD, UV light irradiation, microwave, vacuum activation, and so on. Hence,
according to the reported articles, we will introduce several important methods for
the synthesis of the TiO 2 /graphene composites.
The hydrothermal method involves reactions under controlled temperature and/or
pressure, which is usually performed in stainless steel autoclaves. Liang et al. [42]
108
5 Graphene-Modified TiO 2 with Enhanced Visible Light Photocatalytic Activities
improved.
When the excellent performance of graphene was found, such as high surface
area, excellent mechanical property, outstanding electronic conductivity, special
photoelectrochemical property, and controllable bandgap [31–34], graphene as a
superstar in the material science has attracted much more attention in the past several
years. These properties determine its large potential for applications in electrochemistry and photocatalysis. Moreover, graphene can also potentially act as a support
material, which allows semiconductor particles such as TiO 2 to anchor on its surface.
Recently, the application of graphene in the electrochemical modification on TiO 2
has become a hot spot in the field of photocatalysis [35–40]. The compounding
between graphene and TiO 2 makes the successful connection between nanometer
modules with excellent properties, which greatly improves the transmission efficiency of optical carriers. Undoubtedly, the design and preparation of a series of new
types of efficient TiO 2 /graphene photocatalysts with excellent performance are the
new focus in the photocatalysis.
5.2 TiO 2 /Graphene Composite
5.2.1 Two-Dimensional TiO 2 /Graphene Composites
In 2009, the TiO 2 /graphene was firstly used in the photocatalysis for the
photodegradation of methylene blue (MB) reported by Li and his coworkers
[41]. They successfully synthesized a chemically bonded TiO 2 –graphene composite
with 2D graphene and nanosized P25. The as-prepared TiO 2 /graphene photocatalyst
exhibited extended light absorption range, excellent adsorption of MB, and efficient
photocatalytic activity. From then on, many researchers have reported many kinds of
TiO 2 /graphene composites by using different methods and used them in the
photocatalysis for the degradation of organic pollutants, water splitting, and CO 2
photoreduction. Here, we will discuss the preparation methods, the characterization
methods, and the applications of TiO 2 /graphene in photocatalysis.
5.2.1.1 Preparations
Since the TiO 2 /graphene composite was discovered by the researchers, the
2D-structured TiO 2 /graphene with various morphologies could be synthesized by
different methods, such as hydrothermal, mechanical mixing, pyrolysis, sol–gel,
CVD, UV light irradiation, microwave, vacuum activation, and so on. Hence,
according to the reported articles, we will introduce several important methods for
the synthesis of the TiO 2 /graphene composites.
The hydrothermal method involves reactions under controlled temperature and/or
pressure, which is usually performed in stainless steel autoclaves. Liang et al. [42]
108
5 Graphene-Modified TiO 2 with Enhanced Visible Light Photocatalytic Activities