manipulation (Dong et al. 2017; Ma et al. 2017; Li et al. 2018b). However,
increasing researches about new composite materials of g-C 3 N 4 highlight the potentially photocatalytic ability (Li et al. 2019c).
9.3.1 Heterogeneous Coupling
In order to inhibit recombination of formed electron and hole, achieving different
surfaces of composited catalyst can be an approach. Therefore, heterostructured
catalysts having various potentials of conduction bands and valence bands can be
prepared. Through coupling construction, the excited electrons of conduction band
having higher energy can move to the coupled catalyst conduction band. Analogously, electrons of valence band state of photocatalyst having higher potential
should be excited to the valence band state of the coupled catalyst with lowerenergy state (see Fig. 9.8). The progress is equivalent to the hole transferring of
valence band with lower potential to the valence band of coupled one having higher
potential state. Therefore, recombination rate will be reduced with transferring of
generated electron–hole pairs to different surfaces of new coupled photocatalysts,
resulting in improving photocatalytic efficiency.
UV-Activated Catalysts
Binary Metal Oxides
The binary metal oxides have mainly metal ions with d
0 configuration, which
valence band and conduction band are combined of O 2p orbitals and d metal
ones. The general examples are bimetallic TiO 2 , Nb 2 O 5 , ZrO 2 , Ta 2 O 5 , and WO 3 ,
the anatase phase of the first one with lower band gap energy of 3.2 eV, determined
as water splitting photocatalyst under UV irradiation. In order of effective photon
Fig. 9.7 The band gap influencing for redox potential of the appropriate reactions of g-C 3 N 4 band
edges at pH ¼ 7. (Reprinted with permission of Elsevier from Wen et al. 2017)
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M. Chahkandi and M. Zargazi
increasing researches about new composite materials of g-C 3 N 4 highlight the potentially photocatalytic ability (Li et al. 2019c).
9.3.1 Heterogeneous Coupling
In order to inhibit recombination of formed electron and hole, achieving different
surfaces of composited catalyst can be an approach. Therefore, heterostructured
catalysts having various potentials of conduction bands and valence bands can be
prepared. Through coupling construction, the excited electrons of conduction band
having higher energy can move to the coupled catalyst conduction band. Analogously, electrons of valence band state of photocatalyst having higher potential
should be excited to the valence band state of the coupled catalyst with lowerenergy state (see Fig. 9.8). The progress is equivalent to the hole transferring of
valence band with lower potential to the valence band of coupled one having higher
potential state. Therefore, recombination rate will be reduced with transferring of
generated electron–hole pairs to different surfaces of new coupled photocatalysts,
resulting in improving photocatalytic efficiency.
UV-Activated Catalysts
Binary Metal Oxides
The binary metal oxides have mainly metal ions with d
0 configuration, which
valence band and conduction band are combined of O 2p orbitals and d metal
ones. The general examples are bimetallic TiO 2 , Nb 2 O 5 , ZrO 2 , Ta 2 O 5 , and WO 3 ,
the anatase phase of the first one with lower band gap energy of 3.2 eV, determined
as water splitting photocatalyst under UV irradiation. In order of effective photon
Fig. 9.7 The band gap influencing for redox potential of the appropriate reactions of g-C 3 N 4 band
edges at pH ¼ 7. (Reprinted with permission of Elsevier from Wen et al. 2017)
294
M. Chahkandi and M. Zargazi