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All Journal Jurnal Riset Kimia Indonesian Journal of Chemical Science ALCHEMY Jurnal Penelitian Kimia BERNAS: Jurnal Pengabdian Kepada Masyarakat Jurnal Pengabdian Masyarakat Indonesia Molekul: Jurnal Ilmiah Kimia International Journal of Renewable Energy Development Jurnal Rekayasa Proses
Yuniawan Hidayat
Universitas Sebelas Maret
Religion Agriculture, Biological Sciences & Forestry Humanities Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Dentistry Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Environmental Science Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Mathematics Neuroscience Nursing Public Health Social Sciences Veterinary Other

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The Density Functional Tight Binding (DFTB) Approach for Investigating Vacancy and Doping in Graphene as Hydrogen Storage Hidayat, Yuniawan; Rahmawati, Fitria; Dwi Nugrahaningtyas, Khoirina; Bagus Swandito, Paulus
Jurnal Riset Kimia Vol. 15 No. 1 (2024): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v15i1.635

Abstract

A study on graphene defects for hydrogen storage has been successfully conducted using the Density Functional Tight Binding (DFTB) approach. The research aimed to modify solid materials for hydrogen storage. A 4 × 4 × 1 unit cell was used as the basis, while the supercell used for sampling was enlarged to 40 × 40 × 1. The analyzed data included changes in Density of States (DOS), Fermi level shifts, electronic band structures, formation energy, adsorption energy, and isosurfaces for each graphene orientation. It has been observed that modifying the surface structure of graphene can alter the electronic properties of graphene. This is indicated by shifts in DOS intensity, characterized by increased electronic intensity around the Fermi level total density charge different. The interaction energy between graphene and hydrogen gas has been determined to be -0.0155 eV for H-epoxy graphene, -0.4941 eV for H-monovacancy graphene, and -0.0424 eV for HN-monovacancy graphene. The presence of the vacancy increase the potential to adsorp hydrogen.
The Impact of pH Preparation on the Physical Nature and Metal Phase of Zeolite-Supported Metal Catalyst Nugrahaningtyas, Khoirina Dwi; Budiman, Anatta Wahyu; Sabiila Gusti, Aji Indo; Heraldy, Eddy; Hidayat, Yuniawan
Jurnal Riset Kimia Vol. 15 No. 2 (2024): September
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v15i2.678

Abstract

The synthesis of CoMo/USY catalysts has been widely carried out. However, the bond strength between metal and USY is still a problem. Therefore, this research has synthesised the catalyst with the chelating agent ethylenediaminetetraacetate (EDTA). Apart from that, the effect of pH on the characteristics of the catalyst is also reviewed. This research aims to analyse the effect of preparation pH on catalyst characteristics. In the preparation process, the pH of the solution is set at values of 2, 7, and 8. Catalyst activation includes a calcination process and reduction. The catalyst characterisation uses XRD, GSA, and FTIR instruments to determine phase composition, specific surface area, and functional groups. The result showed that pH preparation significantly influenced the metal loading on the catalyst and reached a maximum at pH 8. The surface area is not directly related to the pH of the preparation but has the opposite property depending on the amount of metal added. Meanwhile, it was found that the CoO and MoO3 phases were achieved on the catalyst by all pH preparations. On the other hand, the CoMo alloys are present on the catalyst at pH 7 and 8, while the Co and Mo elements are visible at pH 2. The difference in pH during the synthesis process impacts the shift in the absorption wave number of the OH vibration.
Study Pore Characterization of γ-Alumina – Activated Carbon Composite Made of Cassava Peels (Manihot esculenta Cranz) Hartini, Hartini; Hidayat, Yuniawan; Mudjijono, Mudjijono
ALCHEMY Jurnal Penelitian Kimia Vol 11, No 1 (2015): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.11.1.106.47-57

Abstract

A composite of γ-alumina and activated carbon made of cassava peels was studied in terms of its pore structures and its properties. The objective of this study was to determine the interaction and structure, as well as the character and pore size of γ-alumina – activated carbon composite.Carbon made of cassava peels was activated by H2SO4 and its activities were tested according to the Indonesian Industrial Standards (SII). The addition of activated carbon into γ-alumina made in variations of 10, 20, 30, 40 and 50 % w/w, of the total weight of 10 grams. The composite of γ-alumina - activated carbon was characterized by FTIR, SAA (Surface Area Analyzer), XRD, and determination of Hysteresis Loop composites.The greater addition of activated carbon to γ-alumina causes intermolecular interactions between –O-H groups form rehydrated hydrogen bonds in the composite is greater. The structure of γ-alumina in the composites remain intact although the percentage of activated carbon in composite is large. The total pore volume and surface area using the BET method of the composite decreases with increasing activated carbon percentage. The greater addition of activated carbon to γ-alumina causes size of mesoporous composites decreased with the characteristic of a composite formed is closer to the activated carbon.
Co-Authors Ana Sofiana, Ana Arif R. Hakim, Arif Arifin Dwi Saputro, Arifin Dwi Bagus Swandito, Paulus Budiman, Anatta Wahyu Candra Purnawan Dwi Nugrahaningtyas, Khoirina Eddy Heraldy Edi Pramono Edy Pramono Fadlulloh, Zaki Fitria Rahmawati Hartini Hendrastuti, Priska Julia I F Nurcahyo, I F IF. Nurcahyo, IF. Ivandini Tribidasari Anggraningrum Jati Wulansari, Jati Joko Sutrisno Khoirina Dwi Nugrahaningtyas Mudjijono Mudjijono, Mudjijono Nugrahaningtyas, Khoirina D Nur Aini Nurcahyo, I. F. Nurcahyo, I.F. Nurcahyo, Idul Fitri Paramartha, I Gusti Ayu Filia Patiha Patiha, Patiha Putri, Denis Octareta Amelia Qurrotul'aini, Nisriina 'Abidah Rahmawati, F Ridwan, Qanita Sabiila Gusti, Aji Indo Saputri, Dini Deviana Sayekti Wahyuningsih Siswandari Siswandari, Siswandari Tiara Diah Saputri, Tiara Diah Triyono . Wega Trisunaryati, Wega Zalfa, Syafira Nur