Dipicolinic acid modified carbon nitride for photocatalytic degradation of acid violet 7 dye and charge storage application

Abstract

The present work focuses on the solar light-driven photocatalytic degradation of Acid Violet 7 (AV7) dye and the electrochemical performance of dipicolinic acid (DPA)-modified polymeric carbon nitride (xDPA-CN) for energy storage applications. The synthesized DPA-CN catalysts show enhanced absorption of visible light compared to pristine polymeric carbon nitride (PCN). Photoluminescence (PL) and electrochemical studies suggest improved charge separation in the optimised 10DPA-CN catalyst. Electrochemical measurements further reveal that 10DPA-CN demonstrates higher capacitance, lower charge-transfer resistance, and superior charge–discharge stability relative to pristine PCN and other modified samples. The 10DPA-CN catalyst also exhibit superior photocatalytic performance towards AV7 dye (50 mg L⁻¹) degradation under visible-light illumination. Reactive oxygen species (ROS) analysis identified the major active species, and a plausible degradation pathway was proposed. As a supercapacitor electrode, the 10DPA-CN shows a high specific capacitance of 558 F g⁻¹ at 1 mA cm⁻² and a coulombic efficiency of 83%, retaining 85.15% of its capacity after 5000 charge–discharge cycles.