the electron–hole recombination on TiO 2 and further extends the absorption of light
in the visible region.
However, most of the applications of TiO 2 /graphene composites in photocatalysis
concentrate on the laboratory conditions, and it is really difficult to achieve its
industrial application in dealing with the environmental issues. The poor dispersion
of TiO 2 on graphene, the weak connection between TiO 2 and graphene, the uncontrollable micromorphology of the composites, and the difficult recycle for the
powders all hinder the industrial application of TiO 2 /graphene composites. Future
works should be focused on the stability of TiO 2 /graphene composites as well as on
their immobilization on appropriate substrates for the operation of photoreactors in
continuous mode, which is close to the industrial application in environmental
issues. Compared with the 2D-structured TiO 2 /graphene, we believe that the
3D-structured TiO 2 /graphene has relative larger potential applications in
photocatalysis, owing to its strong adsorption capacity, excellent photocatalytic
activity, and stable appearance. Arrangement of a serial of TiO 2 /graphene aerogels
or hydrogels with strong mechanical strength together will exhibit an outstanding
adsorption capacity and photocatalytic activity for the organic pollutants. The block
appearance of hydrogels can undergo strong stirring treatment and facilitate the
recycle, which will decrease the cost and promote the industrial applications.
References
1. Fujishima A, Honda K (1972) Electrochemical photolysis of water at a semiconductor electrode. Nature 238:37–38
2. Bach U, Lupo D, Comte P, Moser JE, Weissortel F et al (1998) Solid-state dye-sensitized
mesoporous TiO 2 solar cells with high photon-to-electron conversion efficiencies. Nature
395:583–585
3. Crossland EJW, Noel N, Sivaram V et al (2013) Mesoporous TiO 2 single crystals delivering
enhanced mobility and optoelectronic device performance. Nature 495:215–219
4. O’Regan B, Gratzel M (1991) A low-cost, high-efficiency solar cell based on dye-sensitized
colloidal TiO 2 films. Nature 353:737–740
5. Yang H, Sun C, Qiao S, Zou J, Liu G et al (2008) Anatase TiO 2 single crystals with a large
percentage of reactive facets. Nature 453:638–641
6. Thompson TL, Yates JT (2006) Surface science studies of the photoactivation of TiO 2 new
photochemical processes. Chem Rev 106:4428–4453
7. Linsebigler AL, Lu G, Yates JT (1995) Photocatalysis on TiO 2 surfaces: principles, mechanisms, and selected results. Chem Rev 95:735–758
8. Schneider J, Matsuoka M, Takeuchi M, Zhang J, Horiuchi Y, Anpo M, Bahnemann DW (2014)
Understanding TiO 2 photocatalysis: mechanisms and materials. Chem Rev 114:9919–9986
9. Xing M, Zhang J, Chen F (2009) New approaches to prepare nitrogen-doped TiO 2
photocatalysts and study on their photocatalytic activities in visible light. Appl Catal B Environ
89:563–569
10. Xing M, Zhang J, Chen F (2009) Photocatalytic performance of N-doped TiO 2 adsorbed with
Fe
3+ ions under visible light by a redox treatment. J Phys Chem C 113:12848–12853
11. Xing M, Wu Y, Zhang J, Chen F (2010) Effect of synergy on the visible light activity of B, N
and Fe Co-doped TiO 2 for the degradation of MO. Nanoscale 2:1233–1239
128
5 Graphene-Modified TiO 2 with Enhanced Visible Light Photocatalytic Activities
in the visible region.
However, most of the applications of TiO 2 /graphene composites in photocatalysis
concentrate on the laboratory conditions, and it is really difficult to achieve its
industrial application in dealing with the environmental issues. The poor dispersion
of TiO 2 on graphene, the weak connection between TiO 2 and graphene, the uncontrollable micromorphology of the composites, and the difficult recycle for the
powders all hinder the industrial application of TiO 2 /graphene composites. Future
works should be focused on the stability of TiO 2 /graphene composites as well as on
their immobilization on appropriate substrates for the operation of photoreactors in
continuous mode, which is close to the industrial application in environmental
issues. Compared with the 2D-structured TiO 2 /graphene, we believe that the
3D-structured TiO 2 /graphene has relative larger potential applications in
photocatalysis, owing to its strong adsorption capacity, excellent photocatalytic
activity, and stable appearance. Arrangement of a serial of TiO 2 /graphene aerogels
or hydrogels with strong mechanical strength together will exhibit an outstanding
adsorption capacity and photocatalytic activity for the organic pollutants. The block
appearance of hydrogels can undergo strong stirring treatment and facilitate the
recycle, which will decrease the cost and promote the industrial applications.
References
1. Fujishima A, Honda K (1972) Electrochemical photolysis of water at a semiconductor electrode. Nature 238:37–38
2. Bach U, Lupo D, Comte P, Moser JE, Weissortel F et al (1998) Solid-state dye-sensitized
mesoporous TiO 2 solar cells with high photon-to-electron conversion efficiencies. Nature
395:583–585
3. Crossland EJW, Noel N, Sivaram V et al (2013) Mesoporous TiO 2 single crystals delivering
enhanced mobility and optoelectronic device performance. Nature 495:215–219
4. O’Regan B, Gratzel M (1991) A low-cost, high-efficiency solar cell based on dye-sensitized
colloidal TiO 2 films. Nature 353:737–740
5. Yang H, Sun C, Qiao S, Zou J, Liu G et al (2008) Anatase TiO 2 single crystals with a large
percentage of reactive facets. Nature 453:638–641
6. Thompson TL, Yates JT (2006) Surface science studies of the photoactivation of TiO 2 new
photochemical processes. Chem Rev 106:4428–4453
7. Linsebigler AL, Lu G, Yates JT (1995) Photocatalysis on TiO 2 surfaces: principles, mechanisms, and selected results. Chem Rev 95:735–758
8. Schneider J, Matsuoka M, Takeuchi M, Zhang J, Horiuchi Y, Anpo M, Bahnemann DW (2014)
Understanding TiO 2 photocatalysis: mechanisms and materials. Chem Rev 114:9919–9986
9. Xing M, Zhang J, Chen F (2009) New approaches to prepare nitrogen-doped TiO 2
photocatalysts and study on their photocatalytic activities in visible light. Appl Catal B Environ
89:563–569
10. Xing M, Zhang J, Chen F (2009) Photocatalytic performance of N-doped TiO 2 adsorbed with
Fe
3+ ions under visible light by a redox treatment. J Phys Chem C 113:12848–12853
11. Xing M, Wu Y, Zhang J, Chen F (2010) Effect of synergy on the visible light activity of B, N
and Fe Co-doped TiO 2 for the degradation of MO. Nanoscale 2:1233–1239
128
5 Graphene-Modified TiO 2 with Enhanced Visible Light Photocatalytic Activities