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"Dalam penelitian ini, modifikasi nanostruktur titanium dioksida (TiO₂) dengan menggunakan mineral ilmenit (FeTiO₃) sebagai prekursor alam melalui proses ekstraksi hidrometalurgi, hidrolisis, hidrotermal dan pasca-hidrotermal dikaji. Studi ini mencakup perbandingan modifikasi nanostruktur titanium dioksida dari sintesis (residu ilmenit), komersial (P-25 Degussa) dan hasil ekstraksi ilmenit (titanium oxosulfat) dengan proses perlakuan yang sama. Hasil penelitian menunjukkan bahwa hasil pengolahan mineral ilmenit berupa residu dan filtrat (titanium oxosulfat) dapat digunakan sebagai prekusor alternatif untuk memodifikasi nanostruktur titanium dioksida. Analisis struktur mikro berupa morfologi menunjukkan bahwa precursor dari residu ilmenit hanya dapat membentuk nanostruktur berupa nanosheet TiO₂ sedangkan prekursor dari titanium oxosulfat dapat membentuk nanotube TiO₂ dengan struktur tube dapat terjaga sama seperti struktur tube yang dibentuk dari prekursor komersial. Hasil analisis struktur kristal bahwa ketika residu dan titanium oxosulfat tersebut dilakukan melalui proses hidrotermal dan pasca-hidrotermal maka fase yang diperoleh anatase TiO₂, natrium titanat dan fase Fe₂O₃. Hasil tersebut menunjukkan bahwa masih adanya pengotor (Fe) dalam nanostruktur TiO₂. Lebih lanjut, peningkatan temperatur proses hidrotermal hingga 150°C mendorong peningkatan kristalinitas TiO₂ dari 19,19 menjadi 25,75 nm, seiring dengan peningkatan kristalinitas TiO₂ menyebabkan energi celah pita menurun dari 3,11 menjadi 3,02 eV mendekati energi ruah TiO₂. Hasil perubahan mulai dari morfologi nanopartikel menjadi nanotube TiO₂ dengan struktur tube yang terjaga, kristalinitas yang tinggi dan sifat optik yaitu energi celah pita yang rendah mampu meningkatkan efisiensi degradasi sekitar 96,50%, sedangkan uji fotokatalitik dengan menggunakan cahaya tampak pada nanostruktur TiO₂ yang terbaik pada sampel nanotube TiO₂ prekursor alam dan nanosheet TiO₂ dengan efisiensi degradasi sebesar 97,96 dan 98,34%. Hal ini menunjukkan bahwa hasil pengolahan mineral ilmenit mampu membentuk nanostruktur TiO₂ yang memiliki karakteristik morfologi, sifat struktur kristal dan sifat optik serta perfoma fotokatalitik yang mendekati karakteristik nanostuktur TiO₂ komersial.......In this study, nanostructure modification of titanium dioxide (TiO₂) by using mineral ilmenite (FeTiO₃) as a natural precursor through hydrometallurgical extraction, hydrolysis, hydrothermal, and post-hydrothermal extraction processes were studied. This study includes a comparison of the modified titanium dioxide nanostructure from synthetic (ilmenite residue), commercial (P-25 Degussa), and extracted ilmenite (titanium oxosulphate) with the same treatment process. The results showed that the ilmenite mineral processing results in residue and filtrate (titanium oxosulphate) could be used as alternative precursors to modify titanium dioxide nanostructures. Microstructure analysis in the form of morphology showed that the precursor of ilmenite residu could only form nanostructures in the form of TiO₂ nanosheets. In contrast, precursors of titanium oxosulphate can form TiO₂ nanotubes, with the tube structure being maintained the same as the tube structure formed from commercial precursors. The results of the crystal structure analysis showed that when the residue and titanium oxosulphate were carried out by hydrothermal and post-hydrothermal processes, the phases obtained were TiO₂ anatase, sodium titanate, and Fe₂O₃ phases. These results indicate that there are still impurities (Fe) in the TiO₂ nanostructure. Furthermore, an increase in the hydrothermal process temperature up to 150°C led to an increase in the crystallinity of TiO₂ from 19.19 to 25.75 nm, along with an increase in the crystallinity of TiO₂ causing the bandgap energi to decrease from 3.11 to 3.02 eV approaching the bulk energi of TiO₂. The results of changes  ranging  from nanoparticle morphology to TiO₂ nanotubes with a well-maintained tube structure, high crystallinity, and optical properties, namely low bandgap energi, can increase the degradation efficiency by about 96.50%. while the photocatalytic test using visible light on TiO₂ nanostructures was the best on samples of natural precursor TiO₂ nanotubes and TiO₂ nanosheets with degradation efficiency of 97.96 and 98.34%. This shows that the processing of ilmenite minerals can form TiO₂ nanostructures with morphological characteristics, crystal structure properties, optical properties, and photocatalytic performance that are close to the characteristics of commercial TiO₂ nanostructures."

"Zinc Oxide (ZnO) is an important semiconductor material due to its broad applications, such as in the fields of electronics, optoelectronics, photocatalysts, and solar cells. The main purpose of this work was to investigate the effect of pressure in post-hydrothermal treatment on crystallinity enhancement, crystallite growth, and band gap reduction of ZnO nanoparticles, which could be expected to improve their performance as the semiconductor oxide layer in the dye-sensitized solar cell application. For this purpose, ZnO nanoparticles have been successfully synthesized through the precipitation method, followed by a sequence of thermal treatments including drying, calcination, and Post-hydrothermal Treatment (PHT). For increasing the crystallinity of ZnO nanoparticles, PHT was carried out with a pressure variation of 1 and 3 bar. The resulting nanoparticles were further characterized with X-Ray Diffraction (XRD), Ultra-Violet Visible (UV-Vis) spectroscopy and a Scanning Electron Microscope (SEM). The study showed that by increasing the PHT pressure from 1 to 3 bar caused an adverse effect on the crystallinity, i.e. the crystallite size of ZnO nanoparticles slightly decreased from 27.42 to 26.88 nm. This was expected to be due to the increase of the boiling point of water causing less effective of vapor generated to improve the crystallinity by a cleavage mechanism on the inorganic framework. The band gap energy (Eg), however, was found to increase slightly from 3.25 to 3.26 eV, respectively. Considering the obtained properties, ZnO nanoparticles in this study have the potential to be used as the semiconductor oxide layer in the dye-sensitized solar cells."

"Pada penelitian ini, telah dilakukan sintesis nanopartikel TiO2 melalu proses sol─gel dengan variasi rasio air terhadap prekursor (Rw) yaitu 0.85, 2.00 dan 3.50 selama proses formulasi yang kemudian diikuti perlakukan termal lanjut berupa pengeringan, anil dan pasca-hidrotermal. Karakterisasi XRD dilakukan untuk mengukur besar ukuran kristalit nanopartikel yang dihasilkan. Dari hasil perhitungan, metode pasca-hidrotermal menghasilkan produk dengan ukuran kristalit paling tinggi dibandingkan perlakukan anil dan pengeringan. Ukuran kristalit tertinggi dimiliki sampel Rw = 3.50 cair dengan besar ukuran kristalit 8,566 nm, diikuti Rw = 3.50 gel sebesar 7,614 nm, Rw = 2.00 sebesar 6,853 nm dan Rw = 0.85 sebesar 6,527 nm. Lebih jauh lagi, nanotube TiO2 difabrikasi melalui teknik hidrotermal dengan melarutkan nanopartikel TiO2 hasil perlakuan anil dan serbuk P-25 Degussa ke dalam larutan alkalin sodium hidroksida berkonsentrasi tinggi di dalam otoklaf tersegel. Detil struktur dan morfologi sampel diuji dengan SEM. Hasil investigasi menunjukkan bahwa nanopartikel dengan Rw = 2.00 berhasil dibuat menjadi nanotube dengan diameter 115─269 nm.

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In this study, TiO2 nanoparticles was synthesized via sol−gel process with various water to inorganic precursor ratio (Rw) of 0.85, 2.00 and 3.50 upon sol preparation, followed with subsequent drying, conventional annealing and posthydrothermal treatments. The resulting nanoparticles were characterized using XRD to measure the crystallite size. On the basis of results obtained, the posthydrothermal resulted TiO2 samples with largest crystallite size in comparison to drying and annealing. The largest crystallite size of hydrothermally treated samples is Rw = 3.50 cair with 8,566 nm, followed by Rw = 3.50 gel with 7,614 nm, Rw = 2.00 with 6,853 nm and Rw = 0.85 with 6,527 nm. Furthermore, nanotube TiO2 have been fabricated through a hydrothermal technique where anneal treated nanopartikel TiO2 sol-gel and P-25 Degussa nanopowder was dissolved in highly concentrated alkaline solution of sodium hydroxide (NaOH) in a sealed autoclave. The detail of the structure and morphology of the resulting nanotubes were characterized using SEM. The result of investigation showed that nanoparticle with Rw = 2.00 can be fabricated became nanotubes with its diameter 155─269 nm."

"Among semiconductors, zinc oxide (ZnO) has received great attention due to its wide band-gap and high electron mobility, resulting in various strategic applications. Controlling the physical properties of ZnO is therefore a critical issue in the fabrication of related electronic and optical devices. In this study, ZnO nanorods layers were grown on an ITO glass substrate via chemical bath deposition at low temperature. Prior to the growing process, the layers were deposited using a spin-coating technique. The seeding solution was made by dissolving zinc nitrate tetrahydrate and hexamethylene tetraamine in cold water (0oC) for an hour using a cooler bath. The as-synthesized ZnOs were further subjected to different post-hydrothermal treatment series at a temperature of 150oC for three hours at atmospheric pressure and at 100°C for one hour under one bar of nitrogen gas (N2) pressure. The characterization was performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and UV-Vis spectroscopy. The SEM results showed that the ZnO nanorods were grown as a vertically aligned hexagonal structure, while the XRD patterns showed a high intensity at the (002) plane. On the basis of investigation, it was found that under post-hydrothermal treatment at 150oC for three hours with atmospheric pressure, the synthesis procedure resulted in nanostructures in the form of ZnO rods. Meanwhile, post-hydrothermal treatment at 100°C for one hour under one bar of nitrogen gas (N2) produced ZnO rods and tubes. In general, the post-hydrothermal process provided a high degree of crystallinity. The optimum ZnO layer was obtained after post-hydrothermal treatment at 150oC for three hours at atmospheric pressure, with a crystallite size and band-gap energy of ~18 nm and 3.20 eV, respectively."

"Dalam penelitian ini telah dilakukan sintesis nanopartikel ZnO melalui proses presipitasi, diikuti dengan proses pra-hidrotermal, anil, dan proses pascahidrotermal dengan variasi temperatur 80, 100, 120, dan 150°C. Pengaruh variasi temperatur proses pasca-hidrotermal terhadap ukuran kristalit, kristalinitas, dan energi celah pita nanopartikel diteliti dengan karakterisasi difraksi sinar X dan spektroskopi UV-Vis. Peningkatan temperatur proses pasca-hidrotermal dari 80 hingga 150°C mampu meningkatkan ukuran nanopartikel ZnO dari 11.816 menjadi 13.442 nm, serta menurunkan energi celah pita dari 3.085 menjadi 3.070 eV. Nanopartikel ZnO hasil proses pasca-hidrotermal dengan temperatur 150°C mampu menghasilkan ukuran yang kecil (13.442 nm), kristalinitas yang tinggi, dan energi celah pita yang sama dengan ZnO ruah (3.07 eV. ......In this research, ZnO nanoparticles has been synthesized by precipitation method, followed by pre-hydrothermal, annealing, and post-hydrothermal processes with variation in temperature of 80, 100, 120, and 150°C. The effects of the variation in temperature on the crystallite size, crystallinity, and bandgap energy of ZnO nanoparticles have been investigated by X-Ray Diffraction and UV-Vis spectroscopy. The increase in temperatures from 80 to 150°C has enhanced the crystallite size of ZnO nanoparticles from 11.816 to 13.442 nm and decreased the bandgap energy from 3.085 to 3.070 eV. ZnO nanoparticles derived from posthydrothermal process with temperature of 150°C showed the most-enhanced crystallite size of 13.442 nm and the lowest bandgap energy of 3.070 eV, which is the same as the bandgap energy of bulk ZnO."

"Penelitian teknologi nano pada nanopartikel ZnO untuk aplikasi pelabelan sel memiliki potensi yang besar karena kemampuannya dalam mengemisikan warna hijau. Kemampuan emisi warna hijau dapat ditingkatkan dengan meningkatkan kristalinitas dan menurunkan energi celah pita mendekati material ruahnya. Dalam penelitian ini telah dilakukan sintesis nanopartikel dengan teknik presipitasi yang dikombinasikan dengan perlakuan permukaan berupa selubung silika pada permukaan nanopartikel ZnO membentuk ZnO@SiO2 dan perlakuan panas pascahidrotermal dengan variasi temperatur tahan 80, 100, 120, dan 150°C dengan waktu konstan selama 24 jam, secara khusus ditujukan untuk mengetahui pengaruh perlakuan tersebut terhadap ukuran nanopartikel, kristalinitas dan energi celah pita nanopartikel tersebut. Hasil penelitian menunjukkan bahwa pemberian perlakuan permukaan dan peningkatan temperatur pasca-hidrotermal mampu meningkatkan ukuran kristlit nanopartikel ZnO dari 7.88 menjadi 12.56 nm, serta menurunkan energi celah pita dari 3.223 menjadi 3.156 eV. ......Research on ZnO nanoparticel for cell labeling has great potential due to its ability to emit green light. This ability can be enhanced by improvement its crystallinity and reduction its band gap energy into its bulk (3,07 eV). In the current research, the synthesis of ZnO nanoparticle has been performed, using precipitation technique assisted by surface modification ZnO with silica to form encapsulated silica (ZnO@SiO2) and post-hydrothermal treatment with various holding temperature of 80, 100, 120, and 150°C. These procedures were specifically aimed at studying the effect of these treatments on nanoparticle size, crystallinity, and band gap energy of the resulting nanoparticles. The result of this research showed that surface modification and the increase in post-hydrothermal treatment temperature from 80oC to 150oC has increased nanoparticle ZnO size from 7.88 to 12.56 nm, and decreased the band gap energy from 3.223 to 3.156 eV."