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"Grafena merupakan material komposit yang memiliki karakteristik mekanik, optik, dan konduktivitas yang baik. Dibutuhkan alternatif untuk menurunkan cost dalam proses fabrikasinya, salah satu upayanya adalah mengganti bahan baku menjadi limbah biomassa, digunakan limbah kulit singkong. Metode yang digunakan dalam pembutan grafena adalah mereduksi grafena oksida. Grafena oksida dibuat menggunakan metode Hummers termodifikasi. Metode reduksi kimia adalah metode yang umum digunakan, tetapi memiliki residu yang berbahaya bagi lingkungan. Oleh karena itu, digunakan metode  alternatif yaitu reduksi laser. Proses reduksi dilakukan dalam 4 variasi waktu, yaitu 1, 2, 3, dan 4 jam. Dilakukan beberapa pengujian, diantaranya SEM, FTIR, UV-Vis, dan XRD. Hasil UV-Vis dari proses reduksi grafena oksida didapatkan puncak pada 237 nm untuk 1 jam, 245 untuk 2 jam, dan optimum 3 jam pada 261 nm menunjukkan adanya transisi orbital C=C. Setelah 3 jam, puncak menghilang mengindikasikan terbentuk cacat. Hasil FTIR menunjukkan hilangnya puncak gugus oksigen dan hidroksil. Pengamatan SEM menunjukkan morfologi lembaran tipis dan menggulung serta hasil XRD yang mengalami pergeseran puncak ke daerah 25,7°.

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Graphene is a composite material that has good mechanical, optical and conductivity characteristics. Alternative is needed to reduce costs in the fabrication process, one of the efforts is to replace the raw material to biomass waste  used cassava peel. The method used in making graphene is by reducing graphene oxide. Graphene oxide synthesized using a modified Hummers method. The chemical reduction method is the most commonly used method, but it has residues that are harmful to the environment. Therefore, an alternative method is used, namely laser reduction. Laser reduction used various reduction time range from 1, 2, 3, and 4 hours. Several characterization techniques were utilized, including SEM, FTIR, UV-Vis, and XRD. The UV-Vis results from the process reduction of graphene oxide showed peaks at 237 nm for 1 hour, 245 for 2 hours, and an optimum for 3 hours at 261 nm indicating a C=C orbital transition. After 3 hours, the peaks disappeared indicating defect formed. FTIR results also show the loss of the hydroxyl group peaks, indicating a successful reduction process. SEM observations showed the morphology of thin and rolled sheets. Finally, XRD results or rGO displayed a peak shift back to region 25,7°."

"Since 2004, graphene has risen in popularity owing to its superior properties. However, limits to the scale of production methods have rendered graphene a costly material. Moreover, existing production methods require chemicals that are detrimental to the environment. This study uses Coconut Coir Dust (CCD) as a carbon precursor and an intermediate product in the manufacturing of graphene. Firstly, CCD sieved into a 100 mesh was carbonized using a hydrothermal method at temperatures of 235oC, 250oC, and 265oC, for 4 hours. Following this, the resulting solid residue was pyrolyzed at 1000oC for 2 hours under the protection of nitrogen (N2). The hydrothermal solid residue was labelled CHT (hydrothermal temperature) and the pyrolysis product was named as SP (hydrothermal temperature). Both samples were characterized using SEM, XRD and EDS. In addition, Raman characterization was conducted for SP samples. At the end of the process (SP), the XRD pattern showed two broad peaks centered around 2? ~24o and 44o corresponding to a (002) and (100) graphite plane. This pattern is similar to that of reduced-graphene oxide. SEM images showed a sheet-like microstructure is caused by undegraded lignin. A perforated and corrugated sheet formed after pyrolysis, which subsequently confirms the formation of reduced-graphene oxide. Furthermore, the Raman result indicates that higher hydrothermal temperatures lead to an increasing integrated ID/IG ratio. The ratios were 1.62, 1.71 and 1.77, for SP 235, SP 250, and SP 265, respectively. Research results conclude that the carbonaceous material formed through hydrothermal and pyrolytic processes contained a mixture of an amorphous-carbon form and a graphene-like cluster. Results additionally show a similar structure with reduced-graphene oxide."

"This book focuses on a group of new materials labeled "graphene oxides." It provides a comprehensive overview of graphene oxide-based nanomaterials in terms of their synthesis, structures, properties, and extensive applications in catalysis, separation, filtration, energy storage, and conversion. The book also covers emerging research on graphite oxides and the impact of the research on fundamental and applied sciences. "

"Dalam studi ini, nanokomposit LaMnO3/TiO2 dan LaMnO3/ZnO disintesis menggunakan metode sol-gel. Penambahan material graphene pada nanokomposit LaMnO3/TiO2 dan LaMnO3/ZnO dilakukan dengan metode ko-presipitasi. Sampel tersebut dikarakterisasi dengan menggunakan spektroskopi X-ray Diffraction XRD, UV-Visible Diffuse Reflectance UV-Vis Thermogravimetric Analysis TGA, Fourier Transform Infrared FTIR, Raman dan Brunauer Emmet-Teller BET untuk mengamati struktur kristal, nilai celah energi, stabilitas panas, vibrasi molekul, sifat magnet dan luas permukaan pada sampel. Aktivitas catalytic nanokomposit LaMnO3/TiO2 dan LaMnO3/ZnO dengan variasi molar 1:0.5 menunjukan aktivitas catalytic yang paling baik dibandingkan variasi molar lainnya. Selain itu penambahan material graphene pada nanokomposit dapat meningkatkan aktivitas catalytic dari kedua nanokomposit dan 5 weight percentage wt. graphene menunjukan aktivitas catalytic yang paling baik. Aktivitas catalytic dengan menggabungkan photo dan sono sonophotocatalytic menunjukkan aktivitas catalytic yang lebih baik dibandingkan dengan photo- dan sono-catalytic akibat adanya efek sinergis antara photo- dan sono- catalytic. Penambahan scavenger dilakukan untuk mengetahui spesies aktif yang berperan dalam proses catalytic dan hole merupakan spesies paling aktif yang paling beperan dalam proses catalytic.

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In this study, LaMnO3 TiO2 and LaMnO3 ZnO nanocomposite was synthesized using sol gel method while LaMnO3 TiO2 graphene and LaMnO3 ZnO graphene composite was synthesized using co precipitation. The prepared sample was characterized using X ray diffraction XRD, Thermogravimetric Analysis TGA, Differential Thermal Analysis DTA , Fourier Transform Infrared Spectroscopy FTIR, Raman, Vibrating Sample Magnetometer VSM, UV vis diffuse reflectance UV vis DRS and Brunauer Emmet Teller BET spectroscopy to investigate crystal structure, band gap energy, thermal stability, molecule vibration, magnetization and surface area of the sample. The catalytic activity was performed using ultraviolet and visible light photocatalytic , ultrasonic sonocatalytic, and combination of photocatalytic and sonocatalytic sonophotocatalytic to degrade methylene blue MB. The results show that LaMnO3 TiO2 and LaMnO3 ZnO nanocomposite 1 0.5 have superior catalytic activity. The addition of graphene could increase the degradation of MB and 5 weight percentage wt. of graphene show the highst catalytic activity. Furthermore, the catalytic activity under the combination of visible and ultrasonic show higher catalytic activity that photocatalytic and sonocatalytic activity due to the synergistic effect between photo and sono catalytic. "

"Carbon nanotubes and graphene is a timely second edition of the original Science and Technology of Carbon Nanotubes. Updated to include expanded coverage of the preparation, purification, structural characterization, and common application areas of single- and multi-walled CNT structures, this work compares, contrasts, and, where appropriate, unitizes CNT to graphene. This much expanded second edition reference supports knowledge discovery, production of impactful carbon research, encourages transition between research fields, and aids the formation of emergent applications. New chapters encompass recent developments in the theoretical treatments of electronic and vibrational structures, and magnetic, optical, and electrical solid-state properties, providing a vital base to research. Current and potential applications of both materials, including the prospect for large-scale synthesis of graphene, biological structures, and flexible electronics, are also critically discussed."

"Pada penelitian ini preparasi komposit busa nikel termodifikasi mangan oksida dan graphene dan uji performanya sebagai elektroda untuk superkapasitor telah berhasil dilakukan. Karakterisasi menggunakan SEM-EDX menunjukkan morfologi berupa bercak putih dan terbentuknya lapisan berupa lembaran yang menyelimuti kerangka busa nikel menunjukkan keberadaan mangan oksida dan graphene. Sedangkan karakterisasi dengan Spektroskopi Raman menunjukkan adanya peak yang mengindikasikan D band dan G band  dengan rasio I_D/I_G yang dapat menentukan keberadaan material elektroaktif graphene. Uji elektrokimia menggunakan teknik Cyclic Voltammetry (CV) menunjukkan nilai kapasitansi spesifik tertinggi pada Busa nikel/MnO₂/Graphene yaitu sebesar 1117,32 F/g pada scanrate optimum 5 mV.s^-1. Uji elektrokimia menggunakan teknik Galvanostatic Charge-discharge (GCD) menunjukkan performa terbaik adalah pada Busa nikel/MnO₂/Graphene pada arus yang diberikan sebesar 2 mA, dengan nilai kapasitansi spesifik mencapai 977,77 F/g, densitas energi sebesar 27,5 Wh/kg dan densitas daya sebesar 4500 W/kg. Uji elektrokimia menggunakan teknik Electrochemical Impedance Spectroscopy (EIS) menghasilkan Nyquist plot. Nilai Rct  diperoleh untuk masing-masing elektroda busa nikel/MnO₂, busa nikel/graphene, dan busa nikel/MnO2/graphene adalah sebesar 415 Ω; 580,58 Ω; dan 1460 Ω.

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In this research, the preparation of nickel foam composites modified with manganese oxide and graphene and its performance test as electrodes for supercapacitor has been successfully carried out. Characterization using SEM-EDX showed morphology in the form of white spots and the formation of a layer in the form of a sheet covering the nickel foam framework indicating the presence of manganese oxide and graphene. Meanwhile, the characterization using Raman spectroscopy showed that there was a peak indicating the D band and G band with the I_D/I_G ratio which could determine the presence of graphene electroactive material. The electrochemical test using the Cyclic Voltammetry (CV) technique showed the highest specific capacitance value for MnO₂/graphene/Ni foam, which was 1117.32 F/g at an optimum scan rate of 5 mV.s^-1. The electrochemical test using the Galvanostatic Charge-discharge (GCD) technique shows that the best performance is on MnO₂/graphene/Ni foam at a given current of 2 mA, with a specific capacitance value of 977.77 F/g, an energy density of 27.5 Wh/kg and a power density of 4500 W/kg. Electrochemical tests using the Electrochemical Impedance Spectroscopy (EIS) technique produced a Nyquist plot. The Rct value obtained for each electrode of MnO₂/Ni foam , graphene/Ni foam, and MnO₂/graphene/Ni foam is 415 Ω; 580.58 Ω; and 1460 Ω."

"Penggunaan fotokatalis TiO2 dan modifikasinya dalam produksi hidrogen secara fotokatalitik merupakan salah satu teknologi yang ramah lingkungan. Salah satu solusi untuk mengatasi keterbatasan TiO2 dalam pemanfaatan sinar tampak adalah penambahan g-C3N4 dan grafena yang memiliki kesamaan struktur 2D dengan peran yang berbeda dalam meningkatkan aktivitas fotokatalis. Penelitian ini mengkaji pengaruh loading g-C3N4 dan grafena pada TiO2 serta kombinasinya terhadap kinerja produksi hidrogen secara fotokatalitik. Sintesis katalis pada penelitian ini dilakukan dengan metode impregnasi. Karakterisasi fotokatalis dilakukan pada TiO2 P25, g-C3N4, variasi dari g-C3N4/TiO2 dan G/TiO2, serta g-C3N4/G/TiO2 dengan karakterisasi XRD, UV-Vis, dan FTIR. Uji produksi Hidrogen dilakukan dalam reaktor dengan pencahayaan internal yang dilengkapi lampu UV 20W, dan buret dengan karakterisasi produk H2 menggunakan GC. Akumulasi hidrogen yang diperoleh dengan katalis TiO2 P25, 1% g-C3N4/TiO2, 0,3% G/TiO2, dan g-C3N4/G/TiO2 secara berturut-turut sebesar 327,22 µmol, 661,43 µmol, 727,99 µmol, dan 491,2 µmol mengindikasikan bahwa 0,3% G/TiO2 adalah katalis dengan efektivitas tertinggi dengan band gap 2,97 eV yang dapat meningkatkan produksi hidrogen hingga 2,22 kali lebih tinggi dari TiO2 P25. Kombinasi g-C3N4/G/TiO2 tidak menunjukkan performa maksimal karena keberadaan g-C3N4 dan grafena secara bersamaan diduga menyebabkan adanya efek yang menghambat peran dari masing-masing promotor tersebut dalam memperbaiki performa TiO2 dalam memproduksi H2 secara fotokatalitik.

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The modification of TiO2 as a photocatalyst in photocatalytic hydrogen production is one of the environmentally friendly technologies. One of the solutions to resolve its limitation in utilizing visible light efficiently of TiO2 is the addition of Graphitic Nitride and Graphene that have a similar 2D structure with different role to improve the photocatalytic activity. This study examines the effect of loading g-C3N4 and Graphene in TiO2 along with the combination of those materials to the performance of photocatalytic hydrogen production. The synthesis process on this study was done by an impregnation method. The photocatalyst characterization was conducted on TiO2 P25, g-C3N4, variations of g-C3N4/TiO2 and G/TiO2, also g-C3N4/G/TiO2 with the method of XRD, UV-Vis, and FTIR. Hydrogen production experiment was carried out in a reactor with with 20W UV lamp, and burette with the GC analysis for the product’s characterization. The accumulation of hydrogen products for TiO2 P25, 1% g-C3N4/TiO2, 0,3% G/TiO2, and g-C3N4/G/TiO2 were 327,22 µmol, 661,43 µmol, 727,99 µmol, dan 491,2 µmol, respectively, indicating that 0.3% G/TiO2 is the most effective catalyst with a band gap of 2.97 eV that can improve the hydrogen production up to 2.22 times of TiO2 P25. The g-C3N4/G/TiO2 was not performed maximally because of the presence of g-C3N4 and Graphene simultaneously suspected could block the roles of each promoter to improve the photocatalytic performance of TiO2 in producing H2."

"Limbah katoda grafit dari batu baterai Zinc-Carbon merupakan limbah beracun dengan jumlah melimpah dan menjadi permasalahan bagi lingkungan. Penelitian ini bertujuan untuk mensintesis senyawa sulfonated-GO dan sulfonated-rGO dari limbah grafit batu baterai serta mendapatkan pengaruh penambahan senyawa grafena hasil sintesis terhadap performa fluida pengeboran berbasis air. Purifikasi limbah grafit batu baterai dilakukan dengan teknik leaching asam-basa, sintesis grafena oksida dilakukan dengan metode Hummers termodifikasi, sintesis grafena oksida tereduksi dengan pereduksi asam askorbat untuk kemudian dilakukan rekasi sulfonasi untuk menghasilkan sulfonated-GO dan sulfonated-rGO. Dalam penelitian ini dilakukan variasi jumlah asam askorbat (rGO 1:1,5, rGO 1:2, rGO 1:2,5) dan jenis senyawa grafena yang ditambahkan pada formulasi fluida pengeboran. Dari ketiga variasi yang dilakukan, hasil rGO yang paling baik berdasarkan jumlah lapisan yang terkelupas, kandungan unsur C dan O adalah rGO 1:2,5 dengan jumlah lapisan 7, kandungan unsur C 88,54% dan kandungan unsur O 10,66%. Dalam penelitian ini mengkonfirmasi bahwa SGO dan SrGO terbentuk dengan adanya peak baru pada FTIR sekitar 1173 cm-1 dan 1124 cm-1, yang menunjukkan adanya ikatan S-O dan 1038 cm-1 menunjukkan adanya ikatan s-Phenyl dan terdapat atom S yang mana atom S sebagian besar berasal dari asam sulfanilat. SGO dan SrGO yang dihasilkan dari sintesis grafit dapat diaplikasikan sebagai aditif fluida pengeboran berbasis dan dibandingkan dengan aditif komersial.

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Graphite cathode waste from Zinc-Carbon battery stones is toxic waste in abundance and is a problem for the environment. This study aims to synthesize sulfonated-GO and sulfonated-rGO compounds from graphite waste rock batteries and to obtain the effect of adding synthetic graphene compounds on the performance of water-based drilling fluids. Purification of battery rock graphite waste was carried out using acid-base leaching techniques, graphene oxide synthesis was carried out by the modified Hummers method, reduced graphene oxide synthesis with ascorbic acid reducing then carried out sulfonation reactions to produce sulfonated-GO and sulfonated-rGO. In this study, variations in the amount of ascorbic acid (rGO 1: 1,5, rGO 1: 2, rGO 1: 2,5) and types of graphene compounds were added to the drilling fluid formulation. Of the three variations carried out, the best rGO results were based on the number of layers peeled off, the elemental content of C and O was rGO 1: 2.5 with 7 layers, element C content was 88.54% and elemental O content was 10.66%. In this study, it was confirmed that SGO and SrGO were formed by the presence of new peaks on FTIR of around 1173 cm-1 and 1124 cm-1, which indicated that there were SO bonds and 1038 cm-1 indicated that there were s-Phenyl bonds and there were S atoms, which were S atoms. mostly derived from sulfuric acid. SGO and SrGO produced from graphite synthesis can be applied as drilling fluid based additives and compared with commercial additives."

"Graphene has emerged as a potential candidate to replace traditional CMOS for a number of electronic applications. This book presents the latest advances in graphene nanoelectronics and the potential benefits of using graphene in a wide variety of electronic applications. The book also provides details on various methods to grow graphene, including epitaxial, CVD, and chemical methods. "

"Kami menunjukkan penelitian secara teoretik pada kenaikan nilai magnetisasi dari sistem nanopartikel Fe3O4 dengan adanya penambahan reduced Graphene Oxide (rGO). Data eksperimen telah menunjukkan bahwa magnetisasi sistem nanopartikel Fe3O4 -rGO meningkat dengan peningkatan jumlah rGO sampai sekitar 5 wt%, tetapi menurun kembali dengan bertambah lebih banyaknya jumlah rGO. Kami mengajukkan bahwa kenaikan terjadi dipengaruhi oleh adanya pembalikan spin pada Fe3+ dalam bagian tertrahedral dibantu oleh kekosongan oksigen di perbatasan partikel Fe3O4 . Kekosongan oksigen diinduksi oleh adanya lapisan rGO yang menarik atom oksigen dari permukaan partikel Fe3O4 disekitarnya. Untuk memahami peningkatan mag- netisasi, kami mengkontruksi model Hamiltonian berdasarkan tight-binding untuk sistem nanopartikel Fe3O4 dengan konsentrasi kekosongan oksigen dikontrol melalui konten rGO. Kami menghitung magnetisasi sebagai fungsi dari medan magnet eksternal untuk berbagai variasi wt% rGo. Kami menggunakan metode dynamical mean-field theory dan melakukan perhitungan pada temperatur ruangan. Hasil kami untuk ketergantungan rGO wt% dari magnetisasi saturasi menunjukkan hasil yang sangat sesuai dengan data eksperimen dari sistem nanopartikel Fe3O4 -rGO yang ada. Hasil ini mungkin dapat menkonfirmasi bahwa model kami telah membawa ide paling penting yang dibutuhkan untuk menjelaskan fenomena kenaikan magnetisasi diatas.

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We present a theoretical study on the enhancement of magnetization of Fe3O4 nanoparticle system upon addition of reduced Graphene Oxide (rGO). Experimental data have shown that the magnetization of Fe3O4 -rGO nanoparticle system increases with increasing rGO content up to about 5 wt%, but decreases back as the rGO content increases further. We propose that the enhancement is due to spin-flipping of Fe3+ in the tetrahedral sites assisted by oxygen vacancies at the Fe3O4 particle boundaries. These oxygen vacancies are induced by the presence of rGO flakes that adsorb oxygen atoms from Fe3O4 particles around them. To understand the enhancement of the magnetization we construct a tight-binding based model Hamiltonian for the Fe3O4 nanoparticle system with the concentration of oxygen vacancies being controlled by the rGO content. We calculate the magnetization as a function of the applied magnetic field for various values of rGO wt%. We use the method of dynamical mean-field theory and perform the calculations for a room temperature. Our result for rGO wt% dependence of the saturated magnetization shows a very good agreement with the existing experimental data of the Fe3O4 -rGO nanoparticle system. This result may confirm that our model already carries the most essential idea needed to explain the above phenomenon of magnetization enhancement."