Development of SiO₂/rGO from Rice Husk for Photocatalysis, Antioxidant, Electrochemical and Green Sensor Detection Studies

The present research work describes the extraction and development of reduced graphene (rGO) doped with silicon oxide (SiO2) by simple reflux method. To analyze the structure, size and other characteristics of the synthesized SiO2 /rGO composite, characterization techniques such as XRD, FT-IR SEM and UV studies were used. The photocatalytic activity of the SiO2/rGO nanocomposite was confirmed by degrading malachite green (MG) at a concentration of 20 ppm in 150 min. Following first-order rate kinetics, the synthesized nanocomposite demonstrated a high degradation efficiency of 97% compared to rGO and SiO2. The antioxidant activity of the nanocomposite was tested, indicating significant efficiency in depleting DPPH (2, 2-diphenylpicrylhydrazyl) radical. With an IC50 value of 488.35 mg/mL, a significant reduction of roughly 98% was achieved. From electrochemical evaluation, the specific capacitance (Csp) value of SiO2/rGO (114 F/g) was exhibits higher and sensor detection of bee pollen and cow urine samples were performed. The limit of detection (LOD) and quantization (LOQ) of SiO2 /rGO for bee pollen was found to be 0.114 mM and 0.326 mM and 0.259 mM and 0.457 mM for cow urine. As a result, the novelty of the work can give a valuable application for this material. This can help to reduce waste and improve the economic feasibility of silica production. Furthermore, the SiO2/rGO will provide insight into dye purification, antioxidant, energy storage, and bio-molecule detection features.