Efficient photocatalytic reduction of p-nitrophenol under visible light irradiation based on Ag NPs loaded brown 2D g-C3N4 / g-C3N4 QDs nanocomposite

Abstract

Recently, low-cost graphitic carbon nitride (g-C₃N₄) revealed high photocatalytic activities and provided solutions to environmental pollution. In this study, we synthesized brown mesoporous 2D g-C₃N₄ by calcination dicyandiamide with pluronic P123. This is followed by loading of Ag NPs on the prepared 2D g-C₃N₄ by photodeposition process. After that, a ternary composite 2% Ag/ 2D g-C₃N₄ / g-C₃N₄ QDs heterojunction photocatalyst has been successfully prepared. The prepared nanomaterials were comprehensively characterized by various analysis techniques such as XRD, UV-Vis., BET, XPS, SEM, TEM. This new system exhibited a large surface area with porous structure and a wide absorption of visible light. The results verified that Ag NPs decoration enhanced the charge separation of photo-generated carriers of g-C₃N₄ 2D and g-C₃N₄ QDs, promote significant enhancement in the photocatalytic activity for reduction of p-nitrophenol with a rate constant (k) value of 0.49729 / min in 6 min. This rate is about two-fold higher than that observed for pure g-C₃N₄ 2D and g-C₃N₄ QDs as well as shows an improvement compared to 2% Ag/ g-C₃N₄ 2D and g-C₃N₄ 2D/ g-C₃N₄ QDs. The results open the door to design highly efficient 2D/0D nanocomposite photocatalysts for a wide variety of environmental applications.