2.3.1 g-C 3 N 4 /Cu 2 O Heterojunction Photocatalyst
for Removal of Recalcitrant Pollutants
The sole advantage offered by g-C 3 N 4 as a surface is to prevent aggregation of Cu 2 O
NPs to enhance its metallic, optical, and catalytic properties as studied by Induja
et al. (2019). Researchers have been exploiting these properties for elimination of
organic and inorganic pollutants, bacterial pathogens, and other microbes. The role
of various Cu 2 O morphologies was studied by Chang and Tseng (2018) as depicted
in Fig. 2.8 and claimed that cubic Cu 2 O possessed wide band-gap than rhombic
dodecahedral and sphere Cu 2 O. Also, interaction between Cu 2 O with g-C 3 N 4
exhibited a stronger absorption blue shift of 614.9 nm, influenced by shapes of
Cu 2 O.
Zuo et al. (2018) further investigated the role of specific surface area in pollutant
removal via N 2 -adsorption–desorption isotherm curve. According to the obtained
results, the maximum surface area is g-C 3 N 4 /Cu 2 O (219.2 m
2 /g
À1 ) in molten state
possessed ample channels for removal of MO dye. Mechanism of methyl orange
photodegradation proceeded via migration of photogenerated electrons from Cu 2 O
toward conduction band of g-C 3 N 4 and the simultaneous migration of holes from VB
of g-C 3 N 4 to VB of Cu 2 O as demonstrated in Fig. 2.9.
In detail, Tian et al. (2014) exemplified the transfer of charge carriers in g-C 3 N 4 /
Cu 2 O heterojunction upon visible light irradiation as depicted in Fig. 2.10.
According to band potential values, g-C 3 N 4 is an n-type semiconductor, and Cu 2 O
is a p-type semiconductor with band gap 2.87 and 2.0 eV, respectively, as shown in
Fig. 2.10a. After the contact of both the semiconductors, there is generation of
internal electric filed until the fermi energy level reached an equilibrium point and
eventually lead to heterojunction formation. Upon visible light irradiations as demonstrated in Fig. 2.10b, there was migration of h
+ from valence band of g-C 3 N 4
(1.57 eV) to valence band of Cu 2 O (1.3 eV) and transference of electrons from
Fig. 2.7 Green synthesis of g-C 3 N 4 /Cu 2 O via citrus leaves. (Reprinted with permission from
Induja et al. (2019) copyright@2014 Elsevier Ltd. All rights reserved)
66
P. Raizada et al.
for Removal of Recalcitrant Pollutants
The sole advantage offered by g-C 3 N 4 as a surface is to prevent aggregation of Cu 2 O
NPs to enhance its metallic, optical, and catalytic properties as studied by Induja
et al. (2019). Researchers have been exploiting these properties for elimination of
organic and inorganic pollutants, bacterial pathogens, and other microbes. The role
of various Cu 2 O morphologies was studied by Chang and Tseng (2018) as depicted
in Fig. 2.8 and claimed that cubic Cu 2 O possessed wide band-gap than rhombic
dodecahedral and sphere Cu 2 O. Also, interaction between Cu 2 O with g-C 3 N 4
exhibited a stronger absorption blue shift of 614.9 nm, influenced by shapes of
Cu 2 O.
Zuo et al. (2018) further investigated the role of specific surface area in pollutant
removal via N 2 -adsorption–desorption isotherm curve. According to the obtained
results, the maximum surface area is g-C 3 N 4 /Cu 2 O (219.2 m
2 /g
À1 ) in molten state
possessed ample channels for removal of MO dye. Mechanism of methyl orange
photodegradation proceeded via migration of photogenerated electrons from Cu 2 O
toward conduction band of g-C 3 N 4 and the simultaneous migration of holes from VB
of g-C 3 N 4 to VB of Cu 2 O as demonstrated in Fig. 2.9.
In detail, Tian et al. (2014) exemplified the transfer of charge carriers in g-C 3 N 4 /
Cu 2 O heterojunction upon visible light irradiation as depicted in Fig. 2.10.
According to band potential values, g-C 3 N 4 is an n-type semiconductor, and Cu 2 O
is a p-type semiconductor with band gap 2.87 and 2.0 eV, respectively, as shown in
Fig. 2.10a. After the contact of both the semiconductors, there is generation of
internal electric filed until the fermi energy level reached an equilibrium point and
eventually lead to heterojunction formation. Upon visible light irradiations as demonstrated in Fig. 2.10b, there was migration of h
+ from valence band of g-C 3 N 4
(1.57 eV) to valence band of Cu 2 O (1.3 eV) and transference of electrons from
Fig. 2.7 Green synthesis of g-C 3 N 4 /Cu 2 O via citrus leaves. (Reprinted with permission from
Induja et al. (2019) copyright@2014 Elsevier Ltd. All rights reserved)
66
P. Raizada et al.