Matijevic 1973; Shang et al. 2014), mesoporous low-dimensional nanocomposites
(Bernard and Fan 2006), thin films, and hollow porous structure (Mukherjee et al.
2016). Moreover, controllable size and shape emphasize on low and high indexed
crystal facets (Zhang et al. 2014; Wang et al. 2013). Among all the structures,
polyhedral Cu 2 O are ideal semiconductors for maximum solar energy conversion
and large surface for guest anchoring (Huang et al. 2014). This p-type semiconductor
has been a potential candidate in the fields of water splitting, gas sensor, Li–Nadriven batteries, lubricants, and magnetic memory (Zhang et al. 2006; Dubale et al.
2016; Prucek et al. 2009; Pallecchi et al. 2010; Kim et al. 2016). However, its large
scalable application has been restricted due to rapid transformation of crystal planes,
recombination of charge carriers, and its highly oxidizable nature. To overcome the
abovementioned problems, researchers have approached site-oriented doping and
heterostructuring. Ievskaya et al. (2015) proposed an open-air deposition of Zn–Mg
on thermally oxidized Cu 2 O for purposes of solar cells and energy conversion. For
the purpose of water splitting, Cu 2 O/TiO 2 photocatalyst was synthesized via thermally driven hydrothermal method (Zhao et al. 2016). Photocatalytic ability for
degradation of dyes rhodamine B and methyl orange was studied with
as-synthesized Cu 2 O/SnO 2 and InVO 4 -Cu 2 O-TiO 2 (Joshi et al. 2016; Kong et al.
2017). Chen et al. (2014) fabricated Cu 2 O/g-C 3 N 4 heterojunction through a facile
one-step reduction method to enhance photocatalytic hydrogen production to 70%
more than bare Cu 2 O. In the following sections, we have given an outlook on
synthesis of Cu 2 O/g-C 3 N 4 heterojunction for water purification purpose.
The advancements in structure of g-C 3 N 4 /Cu 2 O nanocomposites have been
accomplished with various methodologies. To achieve the utmost photocatalytic
performance, facet Cu 2 O crystals have been prepared by high and low temperature
and wet chemistry routes. The versatility of photodegradation exhibited by
heterostructure g-C 3 N 4 /Cu 2 O was influenced by operational condition, selectivity
of solvents, and controllable growth to inhibit aggregation. The most widely used
synthetic approach is temperature-driven processes with the use of different solvents.
The crucial vital factors are intimate contact between g-C 3 N 4 and Cu 2 O for efficient
charge transfer, and other is maximized surface area for anchoring of pollutants.
High-temperature-driven fabrication process is most commonly employed for
fabrication of heterostructure. Ji et al. (2018) explained chelation of Cu
+2 in
g-C 3 N 4 obtained via calcination at 550
C using precursors cyanoguanidine and
copper acetate. Anchoring of p-type Cu 2 O with n-type g-C 3 N 4 has been successfully
performed via precursors copper nitrate hexahydrate Cu(NO 3 ) 2 .6H 2 O, urea, and
sodium borohydride (NaBH 4 ). Reduction of Cu
+2 is done by addition of NaBH 4 in
calcined g-C 3 N 4 by Anandan et al. (2017). Highly efficient photocatalyst was
prepared by Zuo et al. (2017) in one-step redox anoxic calcination for removal of
antibiotic chloramphenicol and carbamazepine. The superiority of this process is
the use of attapulgite as a catalyst with inherent hydroxyl radical in structure to fasten
the reaction. The released ammonia gas aids in easy reduction of Cu 2 O and results in
the formation of thin film of Cu
+2 . Similarly, for inactivation of bacteria, g-C 3 N 4 /
Cu 2 O nanocomposite was fabricated via thermal polycondensation of copper acetate
with urea at 550
C for 2 h with dropwise addition of sodium hydroxide as
64
P. Raizada et al.
(Bernard and Fan 2006), thin films, and hollow porous structure (Mukherjee et al.
2016). Moreover, controllable size and shape emphasize on low and high indexed
crystal facets (Zhang et al. 2014; Wang et al. 2013). Among all the structures,
polyhedral Cu 2 O are ideal semiconductors for maximum solar energy conversion
and large surface for guest anchoring (Huang et al. 2014). This p-type semiconductor
has been a potential candidate in the fields of water splitting, gas sensor, Li–Nadriven batteries, lubricants, and magnetic memory (Zhang et al. 2006; Dubale et al.
2016; Prucek et al. 2009; Pallecchi et al. 2010; Kim et al. 2016). However, its large
scalable application has been restricted due to rapid transformation of crystal planes,
recombination of charge carriers, and its highly oxidizable nature. To overcome the
abovementioned problems, researchers have approached site-oriented doping and
heterostructuring. Ievskaya et al. (2015) proposed an open-air deposition of Zn–Mg
on thermally oxidized Cu 2 O for purposes of solar cells and energy conversion. For
the purpose of water splitting, Cu 2 O/TiO 2 photocatalyst was synthesized via thermally driven hydrothermal method (Zhao et al. 2016). Photocatalytic ability for
degradation of dyes rhodamine B and methyl orange was studied with
as-synthesized Cu 2 O/SnO 2 and InVO 4 -Cu 2 O-TiO 2 (Joshi et al. 2016; Kong et al.
2017). Chen et al. (2014) fabricated Cu 2 O/g-C 3 N 4 heterojunction through a facile
one-step reduction method to enhance photocatalytic hydrogen production to 70%
more than bare Cu 2 O. In the following sections, we have given an outlook on
synthesis of Cu 2 O/g-C 3 N 4 heterojunction for water purification purpose.
The advancements in structure of g-C 3 N 4 /Cu 2 O nanocomposites have been
accomplished with various methodologies. To achieve the utmost photocatalytic
performance, facet Cu 2 O crystals have been prepared by high and low temperature
and wet chemistry routes. The versatility of photodegradation exhibited by
heterostructure g-C 3 N 4 /Cu 2 O was influenced by operational condition, selectivity
of solvents, and controllable growth to inhibit aggregation. The most widely used
synthetic approach is temperature-driven processes with the use of different solvents.
The crucial vital factors are intimate contact between g-C 3 N 4 and Cu 2 O for efficient
charge transfer, and other is maximized surface area for anchoring of pollutants.
High-temperature-driven fabrication process is most commonly employed for
fabrication of heterostructure. Ji et al. (2018) explained chelation of Cu
+2 in
g-C 3 N 4 obtained via calcination at 550
C using precursors cyanoguanidine and
copper acetate. Anchoring of p-type Cu 2 O with n-type g-C 3 N 4 has been successfully
performed via precursors copper nitrate hexahydrate Cu(NO 3 ) 2 .6H 2 O, urea, and
sodium borohydride (NaBH 4 ). Reduction of Cu
+2 is done by addition of NaBH 4 in
calcined g-C 3 N 4 by Anandan et al. (2017). Highly efficient photocatalyst was
prepared by Zuo et al. (2017) in one-step redox anoxic calcination for removal of
antibiotic chloramphenicol and carbamazepine. The superiority of this process is
the use of attapulgite as a catalyst with inherent hydroxyl radical in structure to fasten
the reaction. The released ammonia gas aids in easy reduction of Cu 2 O and results in
the formation of thin film of Cu
+2 . Similarly, for inactivation of bacteria, g-C 3 N 4 /
Cu 2 O nanocomposite was fabricated via thermal polycondensation of copper acetate
with urea at 550
C for 2 h with dropwise addition of sodium hydroxide as
64
P. Raizada et al.