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"Nanostructured zinc oxide (ZnO) was synthesized via a sonochemical method. The effect of the duration of ultrasonic irradiation in a continuous mode on the generated particles was investigated. Additionally, the effect of flowing either air or nitrogen during the sonication process was investigated. Zinc nitrate and ammonia water-based solutions were selected as chemicals without the addition of other surfactants. The generated particles indicated that a wurtzite structure of ZnO in a hexagonal phase was formed with a crystalline size that increased as the ultrasound irradiation time increased. The morphology of the generated ZnO particles could be changed from flowerlike to needlelike structures via continuous ultrasound irradiation over one to two hours, resulting in increases in the particle lengths and decreases in the particle diameters from 200 to 80 nm. Photoluminescence intensity was also increased with increases in the ultrasonic irradiation times. Photoluminescence spectra were also influenced by the atmospheric environment. Two bands centered at 390 and 500 nm were generated under a nitrogen environment. On the other hand, a single wide band with a peak at around 430 nm was found for particles generated under an air environment. It can be applied for light emitting diodes (LED) or laser fabrication with a controlled emitting band."

"Nanostructured zincoxide (ZnO) was synthesized via a sonochemical method. The effect of the duration of ultrasonic irradiation in a continuous mode on the generated particles was investigated. Additionally, the effect of flowing either air or nitrogen during the sonication process was investigated. Zinc nitrate andammonia water-based solutions were selected as chemicals without the additionof other surfactants. The generated particles indicated that a wurtzitestructure of ZnO in a hexagonal phase was formed with a crystalline size that increasedas the ultrasound irradiation time increased. The morphology of the generatedZnO particles could be changed from flowerlike to needlelike structures viacontinuous ultrasound irradiation over one to two hours, resulting in increasesin the particle lengths and decreases in the particle diameters from 200 to 80nm. Photoluminescence intensity was also increased with increases in the ultrasonicirradiation times. Photoluminescence spectra were also influenced by theatmospheric environment. Two bands centered at 390 and 500 nm were generatedunder a nitrogen environment. On the other hand, a single wide band with a peakat around 430 nm was found for particles generated under an air environment. Itcan be applied for light emitting diodes (LED) or laser fabrication with acontrolled emitting band."

"In this book, contributions from leadingexperts emphasize basic physical properties, synthesis and processing, and thelatest applications in such areas as energy, catalysis and data storage. Functional metal oxide nanostructuresis an essential reference with aninterest in metal oxides, and particularly in recent progress in defectphysics, strain effects, solution-based synthesis, ionic conduction, and theirapplications."

"This book presents the fabrication of optoelectronic nanodevices. The structures considered are nanowires, nanorods, hybrid semiconductor nanostructures, wide bandgap nanostructures for visible light emitters and graphene. The device applications of these structures are broadly explained. The book deals also with the characterization of semiconductor nanostructures. "

"ABSTRAKGas CO adalah gas yang berbahaya, tidak hanya karena bersifat racun tetapi juga dikarenakan karakteristiknya yang tidak berbau, berwana dan tidak berasa. Pendeteksian secara konvensional tidak memadai untuk diaplikasikan di industri yang membutuhkan kecepatan dan ketepatan pendeteksian. Pengembangan sensor gas mengarah pada bahan metal-oksida semikonduktor seng oksida ZnO . Untuk meningkatkan performa sensor, reduksi ukuran dan proses pendopingan telah menjadi alternatif yang mumpuni. Dopan dengan sifat katalitik, yaitu serium CeO2 , dipilih dalam penelitian ini. Nanopartikel CeO2 disintesis melalui metode presipitasi dengan presipitator NH4OH. Proses optimasi ukuran nanopartikel CeO2 dilakukan dengan memvariasikan temperatur kalsinasi, yaitu 300 oC, 400 oC, 500 oC, 600 oC dan 700 oC . Karakterisasi CeO2 hasil sintesis dilakukan dengan menggunakan FTIR, XRD, PSA, dan TEM. Hasil FTIR mengidentifikasikan bahwa seluruh hasil sintesis mengandung gugus CeO2. Dari hasil karakteriasi XRD dapat diketahui ukuran kristalinitas CeO2 secara berurutan dari temperatur kalsinasi terkecil, yakni 5,3 nm, 5,7 nm, 6,5 nm, 9,9 nm, dan 12,3 nm. Selanjutnya nanopartikel CeO2 dengan ukuran terkecil, yakni hasil kalsinasi dengan temperatur 300 oC, dikarakterisasi lebih lanjut dengan menggunakan PSA dan TEM untuk memastikan sebaran ukurannya. Dari hasil PSA dan TEM diperoleh ukurannya adalah 113 nm dan 4 nm. CeO2 digunakan sebagai dopan dalam pembuatan lapisan tipis dengan memvariasikan konsentrasinya, yakni 0 wt , 4 wt , dan 8 wt . Pada penelitian ini digunakan tiga jenis metode deposisi yakni ultrasonic spray pyrolysis USP , dip-coating, dan spin-coating. Proses pendeposisian lapisan tipis ZnO yang didoping CeO2 dilakukan di atas substrat kaca terlapis emas. Selanjutnya hasil deposisi akan dianalisis morfologi kristalnya dengan menggunakan SEM, komposisi dengan EDS dan performa sensor dengan rangkaian alat deteksi. Morfologi lapisan tipis hasil deposisi dengan metode ultrasonic spray pyrolysis USP dan dip-coating menghasilkan bentuk partikel bulat sementara metode spin-coating menghasilkan bentuk nanowire. Performa sensor diuji dengan mengalirkan gas CO ke ruang uji dengan konsentrasi 100 ppm. Nilai sensitivitas sensor tertinggi bernilai 41 yang diperoleh pada sensor gas lapisan tipis ZnO yang didoping 4 CeO2 hasil deposisi dengan menggunakan metode dip-coating. Waktu respon dan waktu pulih tercepat adalah 5,5 detik dan 7 detik yang diperoleh pada sensor gas lapisan tipis ZnO yang didoping 8 CeO2 hasil deposisi dengan menggunakan metode dip-coating.

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ABSTRACTCarbon monoxide is a dangerous air pollution gas, not only due to its high toxicity but also because of its chemical characteristics exposure to CO occurs without the awareness of an individual. This gas is odorless, tasteless and colorless. Conventional detection is inadequate to apply in industries that require speed and accuracy of detection. The development of gas sensors leads to a metal oxide material of zinc oxide ZnO semiconductors. To improve sensor performance, reduction of size and preparation process has become a viable alternative. Dopants with catalytic properties, ie cerium CeO2 , were selected in this study. The CeO2 nanoparticles were synthesized by precipitation methods with NH4OH precipitators. The process of optimizing the size of CeO2 nanoparticles is done by varying the calcination temperature, 300 oC, 400 oC, 500 oC, 600 oC, and 700 oC. The synthesis of CeO2 characterization was performed using FTIR, XRD, PSA, and TEM. The FTIR results identify that all synthesis products contain the CeO2 group. The XRD result shows that the crystallite size of the cerium oxide increased from 5.3 nm to 12.3 nm as the calcining temperature increased from 300 to 700 oC. Furthermore, CeO2 nanoparticles that calcined at 300 C, are further characterized by using PSA and TEM to confirm the size distribution. From the results of PSA and TEM obtained size is 113 nm and 4 nm. CeO2 was used as a dopant in the manufacture of the thin films with different CeO2 Zn ratios, various concentrations were 0 2 and 6 wt . Ultrasonic spray pyrolysis USP , dip coating, and spin coating are used as the deposition method. The thin films deposited on top of a glass substrate with gold interdigitated electrode for electrical measurements . Furthermore, the deposition results will be analyzed by using SEM, EDS and sensor performance. In order to investigate gas sensing properties, the films deposited on top of glass substrates with gold interdigitated electrodes was heated at various temperature 150 oC, 200 oC, and 250 oC in chamber gas to collect resistance data. The volume of gas CO 100 ppm to be injected was controlled by the duration. The highest sensitivity sensor value is 41 obtained in the 4 CeO2 doped ZnO by dip coating method. Response time and recovery time is 5.5 seconds and 7 seconds is obtained in ZnO layer sensor which is doped 8 CeO2 with deposition using the dip coating method."

"ABSTRAKBerbagai penelitian mengenai teknologi nano terus difokuskan pada nanopartikel semikonduktor seng oksida (ZnO) dengan berbagai potensi strategis yang dimilikinya. Dalam penelitian ini telah dilakukan sintesis nanopartikel ZnO dengan teknik presipitasi yang dikombinasikan dengan perlakuan pra-hidrotermal dengan variasi waktu tahan 0, 24, 48 dan 72 jam yang secara khusus ditujukan untuk menginvestigasi pengaruh perlakuan tersebut terhadap ukuran nanopartikel, kristalinitas dan energi celah pita nanopartikel yang dihasilkan. Hasil penelitian menunjukkan bahwa meningkatnya waktu perlakuan pra-hidrotermal dari 0 hingga 72 jam mampu meningkatkan ukuran nanopartikel ZnO dari 3.47 menjadi 13.85 nm, serta menurunkan energi celah pita dari 3.099 menjadi 3.076 eV.

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ABSTRACTMany research on nanotechnology has been focused on zinc oxide (ZnO) semiconductor nanoparticles which has strategic potentials. In the current research the synthesis of ZnO nanoparticles has been performed, using a precipitation technique assisted by a pre-hydrothermal treatment with various holding time of 0, 24, 48 and72 hours. This route was specifically aimed at investigating the effect of this treatment on the nanocrystallite size, crystallinity and band gap energy of the resulting nanoparticles. The result of investigation showed that an increasing of pre-hydrothermal treatment duration from 0 to 72 hours has increased the crystallite size of ZnO nanoparticles from 3.47 to 13.85 nm, and decreased the band gap energy from 3.099 to 3.076 eV."

"Artikel ini mendeskripsikan penumbuhan nanostruktur ZnO di atas beberapa lembar graphene dengan menggunakan metode hdrotermal dan disertai dengan analisa struktur kristal nano dan sifat optik dari ZnO tersebut. Proses penumbuhan nanostruktur ZnO ini dilakukan secara langsung di atas beberapa lembar grafin tanpa menggunakan seed atau buffer layer dengan metode yang sangat mudah, yaitu metode hidrotermal. Keunggulan metode hidrotermal ini adalah biaya produksi yang rendah dan prosesnya menggunakan temperatur rendah (<100°C), sehingga cocok digunakan untuk memproduksi piranti optoelektronik yang transparan dan fleksibel."

"Dalam penelitian ini, green synthesis nanomaterial β-Ga2O3-M, β-Ga2O3-Hx, dan β-Ga2O3-W via ekstrak daun Cnidoscolus aconitifolius telah berhasil dilakukan. Nanomaterial β-Ga2O3 dianalisis dengan karakterisasi XRD (X-ray Diffraction), UV-Vis DRS (UV-Vis Diffuse Reflectance Spectroscopy), FTIR (Fourier Transform Infrared), SEM (Scanning Electron Microscopy), EDS (Energy Dispersive X-ray Spectroscopy), dan TEM (Transmission Electron Microscopy). Hasil karakterisasi XRD menunjukkan bahwa sistem kristal β-Ga2O3-M, β-Ga2O3-Hx, dan β-Ga2O3-W adalah monoklinik dengan grup ruang C12/m1 fasa tunggal. Pengukuran FTIR mengonfirmasi struktur kristal β-Ga2O3 berupa serapan karakteristik di 662 cm-1 dan 431 cm-1. Spektroskopi UV-Vis DRS menunjukkan sifat optik β-Ga2O3-M, β-Ga2O3-Hx, dan β-Ga2O3-W berupa serapan foton di daerah sinar UV dengan bandgap sebesar 4,59 eV, 4,66 eV, dan 4,61 eV, secara berurutan. Karakterisasi SEM-EDS menunjukkan bahwa β-Ga2O3-M, β-Ga2O3-Hx, dan β-Ga2O3-W memiliki morfologi irregular shape, submicroblock, dan microspindle serta komposisi unsur penyusun yang sesuai secara stoikiometri. Karakterisasi TEM menunjukkan ukuran partikel rata-rata material β-Ga2O3-M, β-Ga2O3-Hx, dan β-Ga2O3-W sebesar 38,18 ± 6,58 nm, 865,85 ± 165,98 nm, dan 2926,01 ± 331,26 nm. Aktivitas fotokatalitik β-Ga2O3-M, β-Ga2O3-Hx, dan β-Ga2O3-W pada proses fotodegradasi metilen biru adalah sebesar 92,64 ± 0,45 %, 20,07 ± 0,97 %, dan 86,70 ± 0,04 %, secara berurutan. Kinetika reaksi fotokatalisis β-Ga2O3-M mengikuti model reaksi orde nol dengan tetapan laju sebesar 4,1 x 10-3 M.menit-1 serta β-Ga2O3-Hx dan β-Ga2O3-W mengikuti model reaksi orde satu semu dengan tetapan laju sebesar 1,6 x 10-3 menit-1 dan 1,64 x 10-2 menit-1, secara berurutan.

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In this research, green synthesis of β-Ga2O3-M, β-Ga2O3-Hx, dan β-Ga2O3-W nanomaterials via Cnidoscolus aconitifolius leaf extract has been successfully carried out. β-Ga2O3 nanomaterials are characterized by XRD (X-ray Diffraction), UV-Vis DRS (UV-Vis Diffuse Reflectance Spectroscopy), FTIR (Fourier Transform Infrared), SEM (Scanning Electron Microscopy), EDS (Energy Dispersive X-ray Spectroscopy), dan TEM (Transmission Electron Microscopy). XRD characterization results showed that β-Ga2O3-M, β-Ga2O3-Hx, and β-Ga2O3-W are single phased and adopted monoclinic crystal system with C12/m1 space group. FTIR measurement confirmed the β-Ga2O3 crystal structure, which showed characteristic absorption in 662 cm-1 and 431 cm-1. UV-Vis DRS spectroscopy showed optical properties of β-Ga2O3-M, β-Ga2O3-Hx, and β-Ga2O3-W which absorbs photon in UV region with bandgap value of 4,59 eV, 4,66 eV, dan 4,61 eV, respectively. SEM-EDS results showed that morphological shape of β-Ga2O3-M, β-Ga2O3-Hx, and β-Ga2O3-W are irregular shape, submicroblock, and microspindle, also elemental composition that corresponds stoichiometrically. TEM characterization results showed that β-Ga2O3-M, β-Ga2O3-Hx, and β-Ga2O3-W have average particle size of 38,18 ± 6,58 nm, 865,85 ± 165,98 nm, and 2926,01 ± 331,26 nm. Photocatalytic activity of β-Ga2O<3-M, β-Ga2O3-Hx, and β-Ga2O3-W in methylene blue photodegradation are 92,64 ± 0,45 %, 20,07 ± 0,97 %, dan 86,70 ± 0,04 %, respectively. Photocatalysis kinetics of β-Ga2O3-M followed the zeroth order reaction model with rate constant of 4,1 x 10-3M.min-1 while β-Ga2O3-Hx and β-Ga2O3-W followed the pseudo first order reaction model with rate constant value of 1,6 x 10-3 min-1 and 1,64 x 10-2 min-1, respectively."

"Busa Poliuretan (Busa PU) adalah salah satu material busa polimer yang banyak digunakan di berbagai bidang, contohnya adalah bidang struktural karena bahannya yang ringan dan kaku. Biasanya, dalam aplikasi struktural material ini digunakan sebagai inti dalam komposit sandwich. Tujuan pebelitian ini adalah menganalisa penambahan selulosa nanofibril (CNF) dari serat daun nanas terhadap sifat mekanik komposit CNF/PU . Selulosa nanofibril yang diambil dari limbah serat daun nanas (PALF) diisolasi dengan perlakuan awal berupa alkalisasi dan dengan perlakuan mekanik menggunakan ultrafine grinder. Penambahan CNF ke dalam busa PU menggunakan metoda tuang polimerisasi in-situ. Isolasi CNF dikarakterisasi dengan menggunakan XRD untuk melihat persentase kristalinitas, menggunakan FTIR untuk melihat pengurangan lignin dan hemiselulosa akibat perlakuan awal, dan TEM untuk mengukur ukuran diameter CNF. Karakterisasi komposit CNF/PU dilakukan dengan menguji tekan dan uji lengkung untuk melihat pengaruh CNF pada komposit CNF/busa PU terhadap sifat mekaniknya, dan morfologi komposit CNF/PU diamati dari citra SEM. Hasilnya, persentase kristalinitas CNF meningkat dari 74,97 % menjadi 75,28%. Pengurangan lignin dan hemiselulosa berhasil dilakukan. Ukuran diameter serat adalah 45-75 nm. Penambahan CNF yang optimum adalah penambahan 3 wt%, berhasil meningkatkan kuat tekan dari 237,02 kPa menjadi 283,70 dan kuat lengkung dari 572,23 kPa menjadi 744,10 kPa.

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Polyurethane foam is a polymer foam material that is widely used in various fields, for example in the structural application because of its light and stiff material. Typically, in structural applications this material is used as the core in sandwich composites. The objective of the current research was to analyze the CNF obtained from pineapple leaf addition to the mechanical properties of CNF/PU composites. Cellulose nanofiber from pineapple leaf fiber waste (PALF) was isolated by pretreatment in the form of alkalization and by mechanical treatment using an ultrafine grinder. The addition of CNF to the PU foam was used the in-situ polymerization pouring method. Isolated CNF was characterized using XRD to study the percentage of crystallinity, using FTIR to study the reduction in lignin and hemicellulose due to pretreatment, and TEM to measure the diameter of the CNF. Characterization of CNF/PU composites was carried out by compressive test and bending test to analyze the effect of CNF on the CNF/PU foam composites on their mechanical properties, and the morphology of CNF/PU composites was observed from SEM images. As a result, the crystallinity percentage of CNF increased from 74.97% to 75.28%. Lignin and hemicellulose was successfully reduced. The fiber diameter was 45-75 nm. The optimum composition of CNF was 3 wt%, succeeded in increasing the compressive strength from 237.02 kPa to 283.70 and the bending strength from 572.23 kPa to 744.10 kPa.

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"Metode Centrifugal Liquid Membrane (CLM) telah berhasil diaplikasikan untuk reduksi Cr(VI) dengan kompleks AuNP@AMS@Fe(II) dalam sistem koloid. Pada penelitian ini sintesis AuNP dilakukan oleh metode CLM dengan mereduksi HAuCl4 menggunakan NaBH4. AuNP yang telah disintesis dimodifikasi dengan ligan AMS dan Fe(II) sehingga terbentuk kompleks AuNP@AMS@Fe(II). AuNP dan kompleks yang terbentuk di karakterisasi dengan Spektrofotometer UV-Vis, PSA dan TEM. Kompleks yang terbentuk diaplikasikan untuk reduksi Cr(VI). Pengukuran dengan spektrofotometer UV-Vis memperlihatkan penurunan intensitas absorbansi Cr(VI) pada λmaks 350 nm yang mengindikasikan terjadinya proses reduksi Cr(VI).Dari analisis kinetika dan mekanisme reaksi perlakuan optimasi dilakukan terhadap variasi rasio mol pereduksi, konsentrasi Cr(VI) dan pH. Aplikasi kompleks dari kondisi ini menghasilkan rasio mol optimum dari aktivitas pereduksi AuNP@AMS@Fe(II) 1:3. Konsentrasi optimum Cr(VI) yang dapat direduksi adalah 9,66 x10-4 M pada pH optimum larutan Cr(VI) sebesar 4,7 dengan persen reduksi yang diperoleh selama 6 menit pengadukan sebesar 97,12% . Tetapan laju reduksi pseudo orde pertama untuk Cr(VI) sebesar 1,703 x10-1 menit-1.

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Centrifugal Liquid Membrane (CLM) method has been successfully applied for Cr(VI) reduction with AuNP@AMS@Fe(II) complex in colloidal system. The synthesis of AuNP held with CLM method by reduction of HAuCl4 with NaBH4. AuNP was modified with MSA ligand and Fe(II) and formed AuNP@AMS@Fe(II) complex compound. AuNP and its complex compound characterized with UV-Vis Spectrophotometer, PSA and TEM Imaging. The complex compound was applied in the reduction of Cr(VI). UV-Vis Spectrophotometer measurement showed the decline of Cr(VI) absorbance intensity at λmaks 350 nm, indicating the reduction of Cr(VI).

Kinetic analysis from optimization reaction held in three parameters: mole ratio of reduction agent variation, Cr(VI) concentration variation, and pH variation. Complex compound application from these conditions resulting optimum mole ratio from AuNP@AMS@Fe(II) reduction agent is 1:3. Optimum concentration of Cr(VI) is 9,66 x10-4 M at optimum pH of Cr(VI) 4,7, with percentage of reduction during 6 minutes stirring is 97,12%. Pseudo order rate constant of Cr(VI) reduction is 1,703 x10-1 minutes-1."