Biologically-mediated synthesis of silver‑zinc oxide incorporated with graphene aerogel: Energy storage applications, photodegradation of dyes, and oil-organic solvents adsorption

Nowadays, graphene aerogels (GA) are known to be a popular and widely used material with the ability to solve environmental problems. To extend the potential of GA, the successful incorporation of Ag-ZnO nanoparticles (NPs) synthesized from betel leaf extract onto the GA framework with a simple and efficient synthesis method. Based on the results, Ag-ZnO/GA material with an optimal Ag-ZnO amount of 200 mg has a synergistic effect on exhibiting an excellent photocatalytic-adsorption capacity. Wherein, the photodegradation efficiency of hazardous dyes including methylene blue, crystal violet, and malachite green achieved 99.8, 98.7, and 100 %, respectively. Besides, the pseudo-first-order adsorption kinetic and Langmuir-Hinshelwood photodegradation kinetic models were applied to assess and propose the adsorption-photocatalytic mechanism. Therewithal, electrochemical properties have also been investigated through cyclic voltammetry (CyV), electrochemical impedance spectroscopy (EIS), and Galvanostatic charge-discharge (GCD) curves with a specific capacitance reaching 250.8 F/g with scan rate at 0.025 V/s. Interestingly, the surface modification using poly(dimethylsiloxane) raised the wetting angle from 26° to 130° in order to boost hydrophobicity and the ability to adsorb oil and organic solvents in water. In particular, the modified Ag-ZnO/GA exhibited a super-adsorption capacity for a wide range of oil (20.0 g g−1) and organic solvents (chloroform and n-hexane) is 26.1 and 12.1 g g−1, respectively. Additionally, the material remained good mechanical strength for practical conditions after 5 cycles of reusability.