7.4 Conclusions
This chapter summarized the recent progress of the research on the preparation
methods and catalytic applications of g-C 3 N 4 /TiO 2 heterojunction catalysts. The
synthesis methods of g-C 3 N 4 /TiO 2 heterojunction catalysts can be simply divided
into three classes according to the order of each component prepared in the preparation process, which includes physically mixing g-C 3 N 4 and TiO 2 , growing TiO 2
on g-C 3 N 4 , and loading g-C 3 N 4 on TiO 2 . In spite of the different advantages and
disadvantages exciting in the three different methods, every one of them can
effectively form the heterojunctions between g-C 3 N 4 and TiO 2 , resulting in
enhanced photocatalytic activity of the catalysts. The g-C 3 N 4 /TiO 2 heterojunction
catalysts with excellent photocatalytic performance have been mainly applied in the
photocatalytic degradation of organic pollutants, photolysis of water for producing
H 2 , photocatalytic reduction of CO 2 , as well as the treatment of heavy metal ion and
inactivation of bacteria.
Apart from the above research, g-C 3 N 4 /TiO 2 heterojunction catalysts are still
worthy of exploration. Some groups found that there exists the phenomenon that the
electron can transfer from dye to TiO 2 , which implies that dye self-sensitized
degradation also exists in this kind of composite system during the degradation
process, providing the possibility for g-C 3 N 4 /TiO 2 heterojunction catalysts being
applied to the dye-sensitized solar cells (DSSC). Moreover, some researchers have
tried to design the ternary heterojunction catalysts such as g-C 3 N 4 /Ag/TiO 2
[41]. The studies on the structure design, the morphology control, and the expansion
of applications related to g-C 3 N 4 /TiO 2 heterojunction catalysts are still significant.
The heterojunction catalysts contain multiple components; therefore the stability of
the heterojunction is not so satisfactory, and the interaction force between different
components is still unknown. The preparation method of heterojunction catalysts
looks more complex than the synthesis of other catalyst, and it still remains a great
challenge for the development of a simplified synthesis method of the heterojunction
catalysts.
References
1. Yang L, Wang L, Xing M et al (2016) Silica nanocrystal/graphene composite with improved
photoelectric and photocatalytic performance. Appl Catal B Environ 180:106–112
2. Cheng C, Tan X, Lu D et al (2015) Carbon-dot-sensitized, nitrogen-doped TiO 2 in mesoporous
silica for water decontamination through nonhydrophobic enrichment–degradation mode.
Chem Eur J 21(49):17944–17950
3. Cheng C, Lu D, Shen B et al (2016) Mesoporous silica-based carbon dot/TiO 2 photocatalyst for
efficient organic pollutant degradation. Microporous Mesoporous Mater 226:79–87
4. Liu F, Yu J, Tu G et al (2017) Carbon nitride coupled Ti-SBA15 catalyst for visible-light-driven
photocatalytic reduction of Cr (VI) and the synergistic oxidation of phenol. Appl Catal B
Environ 201:1–11
References
193
This chapter summarized the recent progress of the research on the preparation
methods and catalytic applications of g-C 3 N 4 /TiO 2 heterojunction catalysts. The
synthesis methods of g-C 3 N 4 /TiO 2 heterojunction catalysts can be simply divided
into three classes according to the order of each component prepared in the preparation process, which includes physically mixing g-C 3 N 4 and TiO 2 , growing TiO 2
on g-C 3 N 4 , and loading g-C 3 N 4 on TiO 2 . In spite of the different advantages and
disadvantages exciting in the three different methods, every one of them can
effectively form the heterojunctions between g-C 3 N 4 and TiO 2 , resulting in
enhanced photocatalytic activity of the catalysts. The g-C 3 N 4 /TiO 2 heterojunction
catalysts with excellent photocatalytic performance have been mainly applied in the
photocatalytic degradation of organic pollutants, photolysis of water for producing
H 2 , photocatalytic reduction of CO 2 , as well as the treatment of heavy metal ion and
inactivation of bacteria.
Apart from the above research, g-C 3 N 4 /TiO 2 heterojunction catalysts are still
worthy of exploration. Some groups found that there exists the phenomenon that the
electron can transfer from dye to TiO 2 , which implies that dye self-sensitized
degradation also exists in this kind of composite system during the degradation
process, providing the possibility for g-C 3 N 4 /TiO 2 heterojunction catalysts being
applied to the dye-sensitized solar cells (DSSC). Moreover, some researchers have
tried to design the ternary heterojunction catalysts such as g-C 3 N 4 /Ag/TiO 2
[41]. The studies on the structure design, the morphology control, and the expansion
of applications related to g-C 3 N 4 /TiO 2 heterojunction catalysts are still significant.
The heterojunction catalysts contain multiple components; therefore the stability of
the heterojunction is not so satisfactory, and the interaction force between different
components is still unknown. The preparation method of heterojunction catalysts
looks more complex than the synthesis of other catalyst, and it still remains a great
challenge for the development of a simplified synthesis method of the heterojunction
catalysts.
References
1. Yang L, Wang L, Xing M et al (2016) Silica nanocrystal/graphene composite with improved
photoelectric and photocatalytic performance. Appl Catal B Environ 180:106–112
2. Cheng C, Tan X, Lu D et al (2015) Carbon-dot-sensitized, nitrogen-doped TiO 2 in mesoporous
silica for water decontamination through nonhydrophobic enrichment–degradation mode.
Chem Eur J 21(49):17944–17950
3. Cheng C, Lu D, Shen B et al (2016) Mesoporous silica-based carbon dot/TiO 2 photocatalyst for
efficient organic pollutant degradation. Microporous Mesoporous Mater 226:79–87
4. Liu F, Yu J, Tu G et al (2017) Carbon nitride coupled Ti-SBA15 catalyst for visible-light-driven
photocatalytic reduction of Cr (VI) and the synergistic oxidation of phenol. Appl Catal B
Environ 201:1–11
References
193