Synthesis of assembled Ag-Bi2O3/rGO composites using hydrothermal and ultrasonication and its application in drug and dye annihilation

The current investigation presents the synthesis of pure bismuth oxide (Bi2O3) and its silver-doped counterpart (Ag-Bi2O3) by the hydrothermal route and loading of the modified material on the rGO sheets to fabricate Ag-Bi2O3/rGO composite via ultrasonication. The structure, morphology, thermal stability, electrical conductivity, optical behavior, and photogenerated charge separation ability of the as-synthesized Bi2O3, Ag-Bi2O3, and Ag-Bi2O3/rGO materials were explored by various physical, thermal, electrical, optical, and electrochemical techniques. XRD, FTIR, and Raman spectra confirm the formation of the as-designed materials with crystallite sizes of 34.61 nm and 40.05 nm for pure and doped materials with unsymmetrical particles of irregular shape, as revealed by morphological investigation. Compared to the pure and rGO-free counterparts, the Ag-Bi2O3/rGO features enhanced visible light absorption (Eg = 2.36 eV), increased electrical conductivity (0.0103 Sm-1), lower charge transfer resistance, decreased flat-band potential (−1.08 V) and higher photocurrent response. The results manifest enhanced solar spectrum harvesting and augmented charge separation and transfer for the designed composite Ag-Bi2O3/rGO. The catalytic activity of these designed materials, Bi2O3, Ag-Bi2O3, and Ag-Bi2O3/rGO, was evaluated by degrading crystal violet (CV) dye and paracetamol (PCM) drugs as typical pollutants. In 90 min of visible-light incidence, 93.95 % (0.026 min−1) CV degradation and 86.48 % (0.0193 min−1) PCM degradation were achieved which discloses the remarkable catalytic activity of rGO-based material. The reaction kinetics for CV and PCM degradation, catalytically active species generation, and catalyst reusability have been systematically investigated to explore the practical applicability of the prepared composite material for solar light harvesting and environmental remediation.