Atiek Rostika Noviyanti
Chemistry Department, Faculty of Mathematics and Science, Universitas Padjadjaran Bandung

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A Compatibility in the Single Cell of the NiO/LSGM/LSCF Atiek Rostika Noviyanti; Claudia Agesti; Yusi Deawati; Dani Gustaman Syarif
Jurnal Kimia Sains dan Aplikasi Vol 23, No 10 (2020): Volume 23 Issue 10 Year 2020
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3124.812 KB) | DOI: 10.14710/jksa.23.10.346-352

Abstract

The compatibility between anode, electrolyte, and cathode in a solid fuel cell determines its performance. Research on the compatibility between fuel cell components is challenging, especially for SOFCs that operate at high temperatures. Therefore, efforts to reduce the operating temperature to become intermediate temperature SOFC (IT-SOFC) are essential to facilitate compatibility between its components. La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) has been recognized as one of the most promising cathode materials for (IT-SOFC) due to its high electronic conductivity and excellent electrical performance. While La0.8Sr0.2Ga0.8Mg0.2O3–δ (LSGM) has a high oxygen ion conductivity at low temperatures, its chemical stability is still not good. LSGM is known to have interface reactivity with other components such as NiO and LSCF in fuel cells. This study looked at the compatibility of NiO/LSGM/LSCF cells prepared by the solid chemical synthesis method. Compatibility evaluation is determined by the Thermal Expansion Coefficient (TEC) parameter using the dilatometric method, Area Specific Resistance (ASR), and TBF area morphology by Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS). While the conductivity of the cells is determined by Electrochemical Impedance Spectroscopy (EIS). NiO/LSGM/LSCF cells have good compatibility with a value of 78.05 kg-1.K.A.s3.µ2 at a temperature of 600°C. The ASR values of cells tend to decrease with increasing temperature and conductivity values at small TEC values. Based on these parameter values, delamination in NiO/LSGM/LSCF cells did not occur.
New Chemicals and Routes for the Preparation of Gelatin/HA Composites using the Wet Precipitation Method Nur Akbar; Asril Pramutadi Andi Mustari; Atiek Rostika Noviyanti
Jurnal Kimia Sains dan Aplikasi Vol 23, No 2 (2020): Volume 23 Issue 2 Year 2020
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1951.965 KB) | DOI: 10.14710/jksa.23.2.46-50

Abstract

Hydroxyapatite (HA) is a material that has many uses in a wide variety of applications such as bone repair, bone implants, and bone drug delivery systems. However, the main weakness of this material is its mechanical strength, which HA is not enough to be directly applied. Gelatin addition is used to improve the mechanical properties that can support material properties for the load-bearing application. This research aimed to obtain gelatin/HA composites with high mechanical strength. This goal is achieved by finding the optimum composite composition (addition of 20, 30, and 40% w/w gelatin), CaO precursors from chicken eggshells, and gradual composite preparation. The preparation of gelatin/HA composites was carried out using the wet precipitation method. The chemical bonding, the compressive strength of HA and gelatin/HA composites, and also morphologies were analyzed by Fourier Transform Infra-Red (FTIR), Universal Testing Machine, and Scanning Electron Microscopy (SEM) respectively. The FTIR spectra show there are chemical bonds between amide and carboxyl in gelatin and Ca2+ in HA. The best compressive strength obtained at the composition of 20% gelatin/HA composite is 99.3 MPa (meanwhile HA is 81.5 MPa). The addition of gelatin to HA increases the particle density; this contributes to the increase in mechanical strength.
Effect of Sodium Periodate on the Adsorption Capacity of Silica-Lignin from Rice Husk on Chromium(VI) Yati B. Yuliyati; Solihudin Solihudin; Atiek Rostika Noviyanti
Jurnal Kimia Sains dan Aplikasi Vol 22, No 6 (2019): Volume 22 Issue 6 Year 2019
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3369.346 KB) | DOI: 10.14710/jksa.22.6.242-249

Abstract

Reactive groups such as silanol, hydroxyl, and carbonyl groups in silica-lignin composites play a role in binding to chromium(VI) ions. The activation of functional groups in silica-lignin can be increased by the addition of an activator such as sodium periodate, which can also oxidize the lignin monomer (guaiasil) to ortho-quinone. This study aimed to obtain silica-lignin composites from rice husks activated by sodium periodate with a high surface area. Composite absorption was tested on chromium(VI) adsorption. Silica-lignin isolation was carried out by using the sol-gel method at concentrations of sodium hydroxide 5, 10, 15, and 20% (b/b). Silica-lignin activated with sodium periodate 10% (b/b) had the smallest particle size of about 8μm, with a surface area of 14.0888 m2.g-1 and followed Halsey isotherm adsorption model, with an adsorption capacity of 0.3054 mg.g-1.
Lowered Sintering Temperature on Synthesis of La9.33Si6O26 (LSO) – La0.8Sr0.2Ga0.8Mg0.2O2.55 (LSGM) Electrolyte Composite and the Electrical Performance on La0.7Ca0.3MnO3 (LCM) Cathode Yoga Trianzar Malik; Atiek Rostika Noviyanti; Dani Gustaman Syarif
Jurnal Kimia Sains dan Aplikasi Vol 21, No 4 (2018): volume 21 Issue 4 Year 2018
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (213.375 KB) | DOI: 10.14710/jksa.21.4.205-210

Abstract

Solid oxide fuel cell (SOFC) is the device that can convert chemical energy into electricity with highest efficiency among other fuel cell. La9.33Si6O26 (LSO) is the potential electrolyte at intermediate operation temperature SOFC. Low ionic conductivity of lanthanum silicate-based electrolyte will lead into bad electrical performance on lanthanum manganite-based anode. In this study, LSO was combine with La0.8Sr0.2Ga0.8Mg0.2O2.55 (LSGM) electrolyte by using conventional solid state reaction to enhance the electrical performance of LSO on LCM cathode. However, pre-requisite high sintering temperature on preparation of LSO-LSGM composite will lead into phase transition phase of LSGM that may affect in decreasing the electrical performance. This study resulted that lowered sintering temperature from its ideal temperature still give an improved electrical performance of LCM/LSO-LSGM/LCM symmetrical cell. The ASR value is 0.14 Ω.cm2 which much lower than its analogous symmetrical cell, LSM/LSO/LSM that was reported before.