14.2.3 Template-Free Methods
This method doesn’t require other substances to serve as templates. By simply
controlling the experimental parameters or selecting an appropriate precursor, the
mesopores can be obtained in the products.
It was reported that MCN materials could be synthesized without using a template
through directly pyrolyzing urea at ambient conditions by Gongxuan Lu et al. In
their experimental procedures, urea powder was put into an alumina crucible with a
cover and calcinated at the temperature of 600
C. The resultant powder was washed
with deionized water and anhydrous ethanol thoroughly, followed by the filtration
and the drying process. As shown in Fig. 14.6a, the obtained MCN materials
possessed layered structure and abundant mesopores. The pore size was in the
range of 20–40 nm [39] (Fig. 14.6b).
Different from producing mesopores in the preparation process of g-C 3 N 4 as
mentioned above , Vishnu Shanker et al. reported a template-free strategy to synthesize MCN materials through a post-ultrasonic treatment of bulk g-C 3 N 4. In their
method, the bulk g-C 3 N 4 was dispersed in an ethanol aqueous solution and then
sonicated at room temperature for 5 h. Porous g-C 3 N 4 sheet with high surface area
and large pore volume was obtained. More attractively, the photocatalytic performance of the MCN was much better than that of bulk g-C 3 N 4 under visible light
irradiation. Besides, the high reusability of the prepared MCN makes the materials
meet the requirement of suitable candidates for practical applications in the field of
photocatalysis [40].
Template-free method is the most ideal synthesis method of MCN. First of all, it
is a quite simple method, because the operation procedure does not need the lengthy
preparation process, saving time and raw materials. Secondly, because there is no
template in this method, no toxic template etchants need to be used, making it also a
Fig. 14.6 (a) TEM image of MCN synthesized by pyrolyzing urea without templates. (b) N 2
adsorption/desorption isotherm of the obtained MCN; inset: pore size distribution [39]. (Reprinted
with permission from Ref. [39]. Copyright 2012, American Chemical Society)
352
14 Synthesis and Modifications of Mesoporous g-C 3 N 4 Photocatalyst
This method doesn’t require other substances to serve as templates. By simply
controlling the experimental parameters or selecting an appropriate precursor, the
mesopores can be obtained in the products.
It was reported that MCN materials could be synthesized without using a template
through directly pyrolyzing urea at ambient conditions by Gongxuan Lu et al. In
their experimental procedures, urea powder was put into an alumina crucible with a
cover and calcinated at the temperature of 600
C. The resultant powder was washed
with deionized water and anhydrous ethanol thoroughly, followed by the filtration
and the drying process. As shown in Fig. 14.6a, the obtained MCN materials
possessed layered structure and abundant mesopores. The pore size was in the
range of 20–40 nm [39] (Fig. 14.6b).
Different from producing mesopores in the preparation process of g-C 3 N 4 as
mentioned above , Vishnu Shanker et al. reported a template-free strategy to synthesize MCN materials through a post-ultrasonic treatment of bulk g-C 3 N 4. In their
method, the bulk g-C 3 N 4 was dispersed in an ethanol aqueous solution and then
sonicated at room temperature for 5 h. Porous g-C 3 N 4 sheet with high surface area
and large pore volume was obtained. More attractively, the photocatalytic performance of the MCN was much better than that of bulk g-C 3 N 4 under visible light
irradiation. Besides, the high reusability of the prepared MCN makes the materials
meet the requirement of suitable candidates for practical applications in the field of
photocatalysis [40].
Template-free method is the most ideal synthesis method of MCN. First of all, it
is a quite simple method, because the operation procedure does not need the lengthy
preparation process, saving time and raw materials. Secondly, because there is no
template in this method, no toxic template etchants need to be used, making it also a
Fig. 14.6 (a) TEM image of MCN synthesized by pyrolyzing urea without templates. (b) N 2
adsorption/desorption isotherm of the obtained MCN; inset: pore size distribution [39]. (Reprinted
with permission from Ref. [39]. Copyright 2012, American Chemical Society)
352
14 Synthesis and Modifications of Mesoporous g-C 3 N 4 Photocatalyst