Journal of Material and Metamaterial Sciences

Energy storage device utilising garlic skin and carbon fibre derived from agricultural and industrial waste: A review

Ayu Atmanda — 2025-01-31

Carbon quantum dots (CQDs) are small-sized nanoparticles (1 – 10 nm) with unique properties such as high conductivity, thermal stability, and fluorescence capability, making them superior materials for energy applications. This research develops an energy storage device based on garlic skin waste and carbon fiber from agricultural and industrial waste. Garlic peel was processed into CQDs using pyrolysis method, while carbon fiber was obtained from methylcellulose. Analytical results showed that CQDs increased the specific capacitance of the gel electrolyte to 110.57 F/g, with excellent cycling stability reaching 96% after 2000 cycles. In addition, the carbon fiber-based electrode showed the highest specific capacitance of 155.58 F/g, energy density of 10.59 Wh/kg, and power density of 4047 W/kg, making it an economical alternative to carbon nanotubes and graphene. Material characterization via TGA, UV-Vis, FTIR, SEM, and TEM confirmed the high thermal stability and quasi-round particle morphology with an average size of 7 nm. The results of this study highlight the potential of CQDs from garlic skin as a sustainable solution for advanced energy storage applications.

Nano rod-shaped core-shell TiO2-SiO2 coating exhibiting superior self-cleaning capabilities under visible light: A review

Dea Stefani — 2025-01-31

Titanium dioxide (TiO₂) is a photocatalytic material widely used in self-cleaning applications due to its ability to decompose organic compounds with free radicals under UV irradiation. However, its limitations in stability and efficiency make it necessary to combine with other materials such as silicon dioxide (SiO₂). This combination forms a core-shell structure where TiO₂ becomes the active core, while SiO₂ acts as a shell that improves stability, extends the absorption spectrum to visible light, and reduces particle agglomeration. This study examines the synthesis and characterization of rod-shaped TiO₂-SiO₂ core-shell nanoparticles that have superior self-cleaning ability under visible light. The synthesis was carried out using a modified hydrothermal method. Structure analysis using SEM showed uniform particle distribution, while XRD analysis confirmed the presence of anatase phase in TiO₂. Self-cleaning evaluation was performed through methylene blue degradation and water contact angle measurement. Results show that this core-shell layer has better photocatalytic activity and hydrophilic properties than pure TiO₂. With these characteristics, this material has great potential to be applied in environmental purification, waste treatment, and renewable energy technologies.

Biosynthesis and characterisation of silver nanoparticles utilising tin (Ficus carica) leaf extracts: A review

Dinda Pratiwi — 2025-01-31

Silver nanoparticles (AgNPs) are materials with various potential applications, ranging from catalysts to antibacterial agents. This study aims to synthesize and characterize AgNPs using tin leaf extract (Ficus carica) as a bioreduction agent in a green synthesis method. The synthesis process was carried out by utilizing AgNO₃ as a precursor and evaluated using UV-Vis spectroscopy, X-ray diffraction (XRD), and scanning transmission electron microscopy (STEM). UV-Vis results showed a characteristic absorption peak at a wavelength of 419 nm, indicating the successful synthesis of AgNPs. XRD analysis identified a face-centered cubic structure with an average particle size of 22.6 nm. STEM revealed a spherical particle morphology with sizes ranging from 11.97 – 20.31 nm. This green synthesis approach provides an environmentally friendly, efficient, and cost-effective solution in the production of AgNPs, with broad potential applications in the medical and technological fields.