mesoporous TiO 2 spheres with a large surface area and rich surface hydroxyl groups
by a light-driven synthetic strategy. It can be used for activating urea under a mild
condition to form g-C 3 N 4 material [57]. Xiaosong Zhou et al. synthesized a g-C 3 N 4 /
TiO 2 nanotube array (CN/TNT) heterojunction photocatalyst with visible light
response via a simple electrochemical method. g-C 3 N 4 polymer was deposited into
the crystallized TiO 2 nanotubes by electrodeposition [58].
In this method, because TiO 2 is prepared firstly, it is allowed for selection or
structure design of TiO 2 , but the high-temperature calcination for the formation of
g-C 3 N 4 is prone to resulting in the aggregation of TiO 2 and may lead to a negative
impact on the improvement of photocatalytic activity.
7.3 The Applications of g-C 3 N 4 /TiO 2 Heterojunction
Catalyst
Compared with single-component catalysts, the g-C 3 N 4 /TiO 2 heterojunction catalysts formed by the combination of g-C 3 N 4 and TiO 2 show greatly enhanced
photocatalytic activity. Therefore, fabricating the g-C 3 N 4 /TiO 2 has many promising
applications in various fields of photocatalysis. Currently, the researches on the
applications of g-C 3 N 4 /TiO 2 mainly focus on the degradation of organic pollutants,
hydrogen generation from water, photocatalytic reduction of CO 2 , treatment of
heavy metal ion, and inactivation of bacteria.
7.3.1 Degradation of Organic Pollutants
With the rapid development of economy, environmental pollution problems have
greatly affected our daily lives, among which the most serious problems are water
pollution and air pollution. The majority in the source of pollution is organic
pollutants. Therefore, the degradation of organic pollutants is a hot research topic
in recent decades. Various kinds of g-C 3 N 4 /TiO 2 heterojunction catalysts have also
been developed and applied to solve these pollution problems.
7.3.1.1 Degradation of Pollutants in Liquid Phase
Many research works have been carried out to examine the photocatalytic degradation of organic dyes such as RhB and AO7 in aqueous solution in the presence of
g-C 3 N 4 /TiO 2 heterojunction catalyst. For instance, methyl blue (MB) was degraded
by g-C 3 N 4 /TiO 2 catalyst which was synthesized by directly heating the mixture of
urea and commercial TiO 2 [31]. The catalyst exhibited efficient photocatalytic
degradation of MB under visible light irradiation. The degradation efficiency can
182
7 The Preparation and Applications of g-C 3 N 4 /TiO 2 Heterojunction Catalysts
by a light-driven synthetic strategy. It can be used for activating urea under a mild
condition to form g-C 3 N 4 material [57]. Xiaosong Zhou et al. synthesized a g-C 3 N 4 /
TiO 2 nanotube array (CN/TNT) heterojunction photocatalyst with visible light
response via a simple electrochemical method. g-C 3 N 4 polymer was deposited into
the crystallized TiO 2 nanotubes by electrodeposition [58].
In this method, because TiO 2 is prepared firstly, it is allowed for selection or
structure design of TiO 2 , but the high-temperature calcination for the formation of
g-C 3 N 4 is prone to resulting in the aggregation of TiO 2 and may lead to a negative
impact on the improvement of photocatalytic activity.
7.3 The Applications of g-C 3 N 4 /TiO 2 Heterojunction
Catalyst
Compared with single-component catalysts, the g-C 3 N 4 /TiO 2 heterojunction catalysts formed by the combination of g-C 3 N 4 and TiO 2 show greatly enhanced
photocatalytic activity. Therefore, fabricating the g-C 3 N 4 /TiO 2 has many promising
applications in various fields of photocatalysis. Currently, the researches on the
applications of g-C 3 N 4 /TiO 2 mainly focus on the degradation of organic pollutants,
hydrogen generation from water, photocatalytic reduction of CO 2 , treatment of
heavy metal ion, and inactivation of bacteria.
7.3.1 Degradation of Organic Pollutants
With the rapid development of economy, environmental pollution problems have
greatly affected our daily lives, among which the most serious problems are water
pollution and air pollution. The majority in the source of pollution is organic
pollutants. Therefore, the degradation of organic pollutants is a hot research topic
in recent decades. Various kinds of g-C 3 N 4 /TiO 2 heterojunction catalysts have also
been developed and applied to solve these pollution problems.
7.3.1.1 Degradation of Pollutants in Liquid Phase
Many research works have been carried out to examine the photocatalytic degradation of organic dyes such as RhB and AO7 in aqueous solution in the presence of
g-C 3 N 4 /TiO 2 heterojunction catalyst. For instance, methyl blue (MB) was degraded
by g-C 3 N 4 /TiO 2 catalyst which was synthesized by directly heating the mixture of
urea and commercial TiO 2 [31]. The catalyst exhibited efficient photocatalytic
degradation of MB under visible light irradiation. The degradation efficiency can
182
7 The Preparation and Applications of g-C 3 N 4 /TiO 2 Heterojunction Catalysts