Development of sustainable au nanoparticle-decorated graphene-derivatives-electroactive polyimide catalysts for efficient water remediation

Utilizing sustainable Xanthosoma sagittifolium leaf powder, this research synthesized reduced graphene oxide (XrGO) and thiol-functionalized XrGO (TXrGO), foundational for producing Au nanoparticle (AuNPs) decorated graphene derivatives-electroactive polyimide (GDs-EPI). Notably, the AuNPs are anchored to GDs-EPI through in-situ reduction of HAuCl₄. The study provided insights into the mechanisms of contaminant transformation and the interactions between the catalysts and contaminants through structural and morphological analyses of these nanocomposites using techniques such as FT-IR, XRD, TGA, SEM/TEM, CV, and XPS. Au/TXrGO-EPI was identified as the most efficient catalyst, attributed to the synergistic effects between AuNPs with smaller sizes (40.0 nm) and GDs-EPI with high electroactivity-promoted electron transport. The degradation efficacy of these nanocomposites against 4-nitrophenol (4-NP) and methylene blue (MB) was assessed in aqueous solutions at room temperature, employing NaBH₄ as a reducing agent. Au/TXrGO-EPI exhibited remarkable catalytic performance and stability, maintaining activity without morphological change over 15 consecutive runs and achieving pseudo-first-order kinetic rate constants of 1.3 × 10⁻² s⁻¹ and 5.4 × 10⁻² s⁻¹ for the reduction of 4-NP and MB reduction, respectively. The study demonstrates that Au/GDs-EPI nanocomposites can serve as strong heterogeneous catalysts for reducing nitroaromatic compounds and toxic dyes in water treatment by chemical reduction, supporting environmentally friendly remediation practices.