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.