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All Journal Indonesian Journal of Chemistry Molekul: Jurnal Ilmiah Kimia
Dewi Agustiningsih, Dewi
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Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Materials Science & Nanotechnology

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Silver-and-Sulphur-Codoped Fe3O4/TiO2 as a Magnetically Separable Photocatalyst for Methylene Blue Degradation under Visible Light Kunarti, Eko Sri; Agustiningsih, Dewi; Pambudi, Fajar Inggit; Rusli, Stefen; Rusdiarso, Bambang
Molekul Vol 19 No 1 (2024)
Publisher : Universitas Jenderal Soedirman

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20884/1.jm.2024.19.1.9508

Abstract

This research aimed to investigate how the addition of silver and sulphur dopants modified the TiO2 photocatalyst to enhance its responsiveness to visible light and improve its photocatalytic activity for methylene blue degradation. In addition, Fe3O4 was also added as a core to add magnetic properties to the photocatalyst material. The Fe3O4/TiO2-Ag/S materials were prepared using FeCl3.6H2O and FeSO4.7H2O as the magnetite precursors, titanium tetraisopropoxide (TTIP) as the TiO2 precursor, while AgNO3 and CH4N2S were used as the sources for silver and sulphur dopants, respectively. The synthesized materials were next characterized using FT-IR, XRD, UV-Vis spectrophotometer, SEM-EDX, TEM, and VSM. The activity of the photocatalyst was then assessed through methylene blue degradation in a closed reactor involving various contained Ag:S ratios and reusability examination. The evaluation of photocatalytic degradation results was performed using UV-Vis spectrophotometry. Afterwards, the research findings indicate that the Fe3O4/TiO2-Ag/S was successfully synthesized and exhibited magnetic properties with a saturation magnetization value of 5.33 emu/g. The highest photocatalytic activity (98.21%) was observed in Fe3O4/TiO2-Ag/S (1:1) with a band gap energy value of 2.64 eV under visible light exposure at pH 10, 120 min, 10 mg mass of the photocatalyst, and methylene blue concentration of 5 mgL-1. Furthermore, the Fe3O4/TiO2-Ag/S photocatalyst was known to perform good stability through four reuse cycles.
Enhanced Photocatalytic Activity and Magnetic Properties of CoFe2O4/TiO2-Ag/S for Visible Light-Driven Photodegradation of Methylene Blue Kunarti, Eko Sri; Agustiningsih, Dewi; Pambudi, Fajar Inggit; Syoufian, Akhmad; Santosa, Sri Juari
Indonesian Journal of Chemistry Vol 25, No 1 (2025)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.100142

Abstract

Environmental concerns drive the need for effective photocatalysts that can operate under visible light to degrade organic pollutants in wastewater. This study investigated TiO2-based photocatalyst doped with Ag and S to enhance its visible-light response, modified further with CoFe2O4 to introduce magnetic properties, resulting in a composite, CoFe2O4/TiO2-Ag/S. The synthesis was carried out by using cobalt nitrate hexahydrate and ferric nitrate nonahydrate for CoFe2O4 precursor, titanium tetraisopropoxide for TiO2 precursor, and silver nitrate with thiourea for Ag and S dopants. Results from characterization analyses, including FTIR, XRD, UV-vis, SEM-EDX, TEM, and VSM, confirmed the composite structure, with magnetic properties reflected in saturation magnetization of 10.69 emu g−1 and an extended UV-vis absorption edge indicating improved visible light activity. Photocatalytic tests for methylene blue degradation showed the highest performance (92%) with a 1:1 Ag:S ratio under visible light at pH 10 over 120 min, using 20 mg of catalyst in 5 ppm solution. Additionally, the composite demonstrated strong stability, retaining efficiency across six cycles of reuse.
Introducing Cu(II) onto SiO2-TiO2 with Rice Husk Ash as the Source of Silica and Its Catalytic Activity for Kumada Cross-coupling Reaction to Produce Biphenyl Compound Agustiningsih, Dewi; Nuryono, Nuryono; Santosa, Sri Juari; Kunarti, Eko Sri
Indonesian Journal of Chemistry Vol 25, No 3 (2025)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.99296

Abstract

This research studied the preparation of SiO2-TiO2/Cu(II) by utilizing rice husk ash as the SiO2 precursor, and evaluated its efficiency as a heterogeneous catalyst in biphenyl synthesis through Kumada cross-coupling reaction, which is widely known as an important intermediate in pharmacology and agriculture manufacturing. In this study, the catalyst preparation was conducted by extracting SiO2 from rice husk ash, combining it with TiO2, and introducing Cu(II) onto its surface with CuCl2·2H2O as the precursor with various concentration of Cu(II). Comprehensive characterization using techniques such as IR, XRD, XRF, DLS, N2 isotherm adsorption-desorption, ICP-AES, STEM-EDS, TEM, UV-vis spectrometry, and TGA was conducted to examine the catalyst properties. Catalyst activity was evaluated in the Kumada cross-coupling reaction, using phenylmagnesium bromide and bromobenzene as reactants under stirring-heating condition, and the products were analyzed using GC-FID method. The characterization results indicated that the preparation of SiO2-TiO2/Cu(II) materials was successfully conducted and Cu(II) was formed as Cu(OH)2. The catalyst considerably promoted the Kumada cross-coupling reaction with a biphenyl yield of 78.85% at 50 °C for 6 h under stirring-heating method. Furthermore, catalyst reusability test demonstrated that the catalyst sustained performance over three cycles without losing its activity significantly. Interestingly, SiO2-TiO2 was observed to function primarily as support material and adsorbent, immobilizing Cu(II) and enhancing reactant reduction but not directly influencing biphenyl formation. Overall, this study contributes to the understanding of SiO2-TiO2/Cu(II) catalyst preparation and its application in biphenyl synthesis, offering insights into catalyst design and performance optimization for future applications in organic synthesis.
Co-Authors Akhmad Syoufian Bambang Rusdiarso Eko Sri Kunarti Nuryono Nuryono Pambudi, Fajar Inggit Rusli, Stefen Sri Juari Santosa