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All Journal Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Science and Technology Indonesia Greensusmater
Januar Widakdo
National Taiwan University Of Science And Technology
Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Earth & Planetary Sciences Education Environmental Science Materials Science & Nanotechnology Physics

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Journal : Greensusmater

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Thermal annealing tailors crystallinity and magnetism in silica coated Ni-Zn ferrite (SiO2@NiZnFe2O4) nanoparticles Widakdo, Januar
Greensusmater Vol. 2 No. 2 (2025)
Publisher : Green and Sustainable Materials Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62755/greensusmater.2025.2.2.30-35

Abstract

Ni0.5Zn0.5Fe2O4 nanoparticles were synthesized using a co-precipitation method followed by annealing at different temperatures to investigate their structural, morphological, and magnetic properties. X-ray diffraction (XRD) confirmed the formation of a single-phase spinel structure, with increased crystallinity and grain growth observed at higher annealing temperatures. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) further revealed a transition from small, aggregated nanoparticles to well-defined crystalline grains. Magnetic hysteresis measurements demonstrated a significant enhancement in saturation magnetization (Ms) and coercivity (Hc) with increasing temperature, reaching up to 55.15 emu/g and 253.23 Oe, respectively, at 800 °C. These improvements are attributed to reduced surface spin disorder and increased magnetic domain alignment due to grain growth. The results underscore the importance of annealing temperature in tailoring the magnetic behavior and structural properties of Ni–Zn ferrite nanoparticles for potential applications in magnetic and electronic devices.
Development and materials characterization of hydrothermally grown niobium-doped BiVO4 for ciprofloxacin and methylene blue degradation Kurnia, Nadiya Rifqah; Amanda, Tia; Nurfitria, Rima; Aflaha, Rizky; Widakdo, Januar; Rianjanu, Aditya
Greensusmater Vol. 2 No. 2 (2025)
Publisher : Green and Sustainable Materials Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62755/greensusmater.2025.2.2.55-61

Abstract

This study reports the synthesis and characterization of niobium-doped BiVO4 (NbX-BiVO4, X = 0, 2, 4, 6 mol%) photocatalysts via a hydrothermal method, aimed at enhancing the degradation of organic pollutants under UV irradiation. X-ray diffraction (XRD) analysis confirmed the preservation of the monoclinic BiVO4 structure in all samples, although minor secondary features were detected in doped compositions. Field emission scanning electron microscope (FESEM) imaging revealed progressively rougher, nanostructured surfaces with increasing Nb content, while UV-Vis and photoluminescence (PL) spectroscopy indicated modified band structures and reduced recombination rates. Photocatalytic performance was evaluated using ciprofloxacin (CIP) and methylene blue (MB) as model pollutants. For CIP, the highest activity was achieved by Nb6-BiVO4 (k value of 0.09 min‒1 g–1), attributable to enhanced charge separation and increased surface texture. In contrast, MB degradation favored the undoped BiVO4 (k value of 0.29 min‒1 g–1) due to stronger dye adsorption, despite the optical improvements in doped samples. The findings demonstrate that Nb doping improves BiVO4 photocatalytic activity through synergistic structural and electronic effects, with pollutant-specific responses highlighting the importance of matching catalyst design to target contaminant properties.
Co-Authors Aflaha, Rizky Amanda, Tia Anawati, Anawati Budhy Kurniawan Canggih Setya Budi Fadly Azril Priodani Febri Rismaningsih Hannah Faye M. Austria Kurnia, Nadiya Rifqah Masno Ginting Naibaho, Marzuki Nehan, Phahul Zhemas Zul Novita Nurfitria, Rima Ramlan Rianjanu, Aditya Tsung Han-Huang Vitayaya, Okvarahireka Wei-Song Hung Wisnu Ari Adi