Plasmon-enhanced photocatalytic activity in the visible range using AgNPs/polydopamine/graphitic carbon nitride nanocomposite

Abstract

Developing an efficient visible-light-driven photocatalyst is believed to be a practical solution for clean energy and environmental remediation. The present study aimed to broaden current knowledge of the graphitic carbon nitride (g-C3N4)-based plasmonic photocatalysts by decorating polydopamine-grafted g-C3N4 (PDA/g-C3N4) with silver nanoparticles (AgNPs). The nanocomposite was prepared using a facile synthesis method, while XPS and microscopy measurements confirmed the homogenous dispersion of AgNPs on PDA/g-C3N4. AgNPs successfully reduced the recombination rate of photoinduced electron-hole pairs. The calculated bandgap energy was decreased from 2.7 eV for pure g-C3N4 to 2.1 eV for AgNPs/PDA/g-C3N4. The developed AgNPs/PDA/g-C3N4 nanocomposite showed superior performance in degrading methylene blue (MB) up to 96% in less than two hours which is 6 and 3 times faster than g-C3N4 and PDA/g-C3N4, respectively. The developed photocatalyst maintained this performance after four successive runs, which proves its excellent chemical stability. The radical scavenger experiment was used to assess the role of active species in the degradation reaction using the AgNPs/PDA/g-C3N4. The kinetics of the degradation reaction was modeled using pseudo-first-order kinetics with a high-rate constant of 0.022 min−1. The plasmon-enhanced photocatalyst showed promising performance for the degradation of organic pollutants using a low-power lamp with potential application in environmental remediation.