Figure. 17.3. Modification methods for g-C3N4 and various doping strategies.

Modification Strategies of g-C3N4 for Potential Applications in Photocatalysis 295

Figure 17.3. Modification methods for g-C3N4 and various doping strategies.

the ITO substrate was placed above the thiourea and melamine mixture in a crucible before it was

moved to the muffle furnace. There are some benefits and drawbacks of CVD. CVD does not require

a high vacuum to manufacture high-purity composites and may deposit various materials.

In contrast, a high vacuum environment is needed for Physical Vapor Deposition (PVD), which

includes sputtering. The disadvantage of CVD is that several CVD precursors, such as Ni (CO)4,

B2H6 and SiCl4, are expensive, extremely poisonous, explosive or corrosive. This process can also

produce dangerous byproducts such as CO or HF. The substrates are restricted since they need to

withstand high temperatures.

17.3.2 Solid-state Reaction

“The solid-state reaction is generated by contact, reaction, nucleation and crystal growth between

solid interfaces at high temperature” (Baughman 1974, Wang et al. 2001). Reaction parameters

such as pressures and temperature of synthesis are varied to control the crystallinity, morphology

and properties of the g-C3N4. Lu et al. 2007 used high pressure to make g-C3N4 material whose

crystallinity could be changed. Under 40 MPa and 220°C, sodium azide and 1,3,5-trichlorotriazine

were mixed for this method. It is important to note that as the pressure in the vessel went up,

g-C3N4 became more crystalline. When Zn particles were added to the reactor, the shape changed

into nanowires, which was the most crucial change.

17.3.3 Electrochemical Deposition

“Electrochemical deposition is a method in which current moves through positive and negative ions

in an electrolyte solution under the influence of an external electric field.” This causes electrons

to be oxidized and reduced on the electrodes to form coatings. This method has received attention

because it can make products better in terms of their quality and properties. Fu et al. (1999), Li et al.

(2017), Shaikh et al. (2017) were the first to use the electrodeposition method to make g-C3N4 from