Sustainable Electrochemical Synthesis of Porous g-C<sub>3</sub>N<sub>4</sub> Nanosheets via 3D-Printed Platinized Electrodes for Enhanced Photocatalytic Activity.

Abstract

Graphitic carbon nitride (g-C₃N₄), a polymeric metal-free catalyst, is extensively used to degrade industrial toxic waste that contaminates the aqueous system. However, commonly synthesized bulk g-C₃N₄ is prone to agglomeration, leading to low surface area with fewer effective photoactive centers, limiting its potential toward the facile separation of photo-excitons and resulting in low photocatalytic activity. This study introduces an innovative electrochemical synthesis of in situ exfoliated porous g-C₃N₄ nanosheets (GCN NSs) featuring a large surface area with effective separation of photo-excitons, leading to the facile production of reactive oxygen species (ROS). The GCN NSs are uniformly dispersed in an alkaline solution grown via a newly designed electrochemical process using 3D-printed platinumized titanium mesh as both anode and cathode under rigorous stirring for 40 min. The morphological study, along with surface area determination, reveals that the as-grown carbonaceous matrix is highly exfoliated with an inherent nanoporous architecture, having a high surface area of 163.73 m² g^-1 with an average pore diameter of 8.311 nm. The electrochemically synthesized GCN NSs demonstrate excellent charge transfer kinetics with low charge transfer resistance and superior photocatalytic activity of 98% degradation efficiency against various organic dyes (concentration of 10 ppm) under simulated solar irradiation for 120 min with 5 mg of catalyst. Kinetic studies of the photodegradation process indicate that the reaction follows pseudo-first-order kinetics, with the rate constant of 3.59 × 10^-2 min^-1, which is approximately 1.8 times higher as compared to the recent findings. A plausible mechanistic understanding reveals that photogenerated holes and hydroxyl radicals (^•OH) are the primary species for the overall photodegradation process. The stability test depicts that the photocatalyst maintains its efficiency over five consecutive runs with a minimum loss of 7%. This research offers valuable insights into the design and synthesis of advanced photocatalysts with optimized architectures for enhanced industrial waste management.