Photocatalytic Performance of Alkaline Activated Graphitic Carbon Nitride Under Blue LED Light

Abstract

Graphitic carbon nitride (g-C3N4) is a metal-free photocatalyst with visible light response. However, the disadvantages limit its application in a wider range, such as its small specific surface areas, fewer active sites, narrow visible light absorption range and high photogenic carrier recombination. In this paper, NaOH was used as activator for alkaline activation of g-C3N4. The phase composition, micromorphology, surface chemical state and optical properties of g-C3N4 after activation were tested. The photocatalytic performance of g-C3N4 over organic dyes was also tested. The results showed that Na+ entered the interlayers of g-C3N4, expanding the spaces between layers. The specific surface area and pore volume of powder were increased. The active sites were increased. The band gap was decreased, and the photogenic carrier recombination was reduced. Alkaline activated g-C3N4 had better adsorption and degradation performance over rhodamine B and methyl orange than inactivated g-C3N4. Therefore, the alkaline activated g-C3N4 promotes its further application in the field of wastewater treatment. This work sheds light on the material modification through a simple method with the aim to efficiently use solar energy.

Enhancement of graphitic carbon nitride (g‐C3N4) assisted photodegradation of Rhodamine B under visible light

“…The value of band gap energy is calculated approximately according to the formula of Eg=1240/λg, where Eg is referred to as the band gap energy of material; λg is the optical absorption edge of the semiconductor [33] . The band gap value of photoactive g‐C 3 N 4 material was estimated to be 2.6260 from tangent drawn to Tauc plot intercepts at the horizontal axis for bandgap value shown in Figure 2(b) [34,35] . The semiconductor band gap energy can be measured using the equation 1 [36,37] …”

“…[33] The band gap value of photoactive g-C 3 N 4 material was estimated to be 2.6260 from tangent drawn to Tauc plot intercepts at the horizontal axis for bandgap value shown in Figure 2(b). [34,35] The semiconductor band gap energy can be measured using the equation ( 1). [36,37]…”