Fabrication of high-performance fluorine doped–tin oxide film using flame-assisted spray deposition

A high-performance fluorine–doped tin oxide (FTO) film was fabricated by flame-assisted spray deposition method. By varying the NH4F doping concentration, the optimal concentration was established as 8 at.%. X-ray diffractograms confirmed that the as-grown FTO film was tetragonal SnO2. In addition, the FTO film was comprised of nano-sized grains ranging from 40 to 50 nm. The heat-treated FTO film exhibited a sheet resistance of 21.8 Ω/ with an average transmittance of 81.9% in the visible region (λ = 400–800 nm). The figures of merit shows that the prepared FTO film can be used for highly efficient dye-sensitized solar cells electrodes

SINTESA NANOFIBER TITANIUM DIOKSIDA (TiO2) ANATASE MENGGUNAKAN METODE ELECTROSPINNING

SYNTHESIS OF ANATASE TITANIUM DIOXIDE (TiO2) NANOFIBER BY ELECTROSPINNING METHOD. This research reported the synthesis of nanofiber anatase titanium dioxide (TiO2) using electrospinning. To produce nanofiber, the precursor solution was passed through a capillary of syringes given a positive DC voltage of 13 kV and then as-prepared nanofiber annealed at temperature of 500°C for 1 hour. The annealed samples were then analyzed using a scanning electron microscope (SEM) and x-ray diffractometer (XRD). In this study, the effect of changes in the flow rate of the precursor solution and the weight of raw material of titanium tetraisopropoxide (TTIP) to the crystallinity and morphology of the sample were systematically investigated. This research resulted that the TiO2 nanofiber have a mixed phase between anatase and rutile. The amount of rutile TiO2 could be reduced by increasing the flow rate of precursor solution. The optimum flow rate to obtain the pure anatase TiO2 was adjusted at 2.0 mL/h. In addition. TTIP weight affected the morphology of nanofiber which by increasing the amount of TTIP resulted morphological change to become more dense and uniform in shape and size. Keywords: anatase; electrospinning; nanofiber; rutile; titania Abstrak Pada penelitian ini telah berhasil dibuat nanofiber titanium dioksida (TiO2) anatase dengan menggunakan metode electrospinning. Nanofiber TiO2 dihasilkan dengan cara melewatkan larutan prekursor pada jarum suntik yang diberi tegangan DC positif 13 kV pada ujungnya. Fiber hasil spinning kemudian dikalsinasi pada suhu 500°C selama 1 jam. Sampel yang telah dikalsinasi kemudian dianalisis menggunakan scanning electron microscope (SEM) dan x-ray diffractometer (XRD). Pada penelitian ini pengaruh dari perubahan laju aliran larutan prekursor dan berat material baku titanium tetraisopropoxide (TTIP) terhadap sifat kristal dan morfologi sampel dikaji secara sistematis.  Dari penelitian ini diperoleh bahwa TiO2 yang dihasilkan memiliki fase campuran antara anatase dan rutile, namun dengan menaikkan laju aliran prekursor mampu menurunkan jumlah fase rutilenya sehingga pada laju aliran 2,0 mL/h diperoleh nanofiber TiO2 dengan fase anatase murni. Berat TTIP sangat mempengaruhi morfologi nanofiber yang diperoleh dimana dengan menaikkan jumlah TTIP morfologi fiber mangalami perubahan menjadi lebih padat (dense) dan lebih seragam baik bentuk dan ukurannya. Kata kunci: anatase; electrospinning; nanofiber; rutile; titani

CuO/WO3 and Pt/WO3 nanocatalysts for efficient pollutant degradation using visible light irradiation

CuO/WO3 and Pt/WO3 nanocatalysts with a nanorod morphology were used for photodegradation of organic compounds using visible light irradiation. Both nanocatalysts were prepared using flame assisted spray pyrolysis method (FASP). The prepared nanocatalysts were mechanically stable during the agitation treatment for the photodegradation test due to good interconnection between WO3 and co-catalysts. The enhancement of photocatalytic activity was observed after the addition of CuO and Pt as co-catalysts. The addition of CuO would change the morphology of WO3 from nanorods to cubic. The optimal concentration of the CuO addition was 0.33 wt.%. A low Pt concentration (0.12 wt.%) was required for optimal photocatalytic activity of the Pt/WO3 nanocomposite. The addition of Pt affected neither the morphology nor the crystallite structure of WO3

Synthesis of Hard Carbon from Waste Teak Wood Powder as Anode Material for Lithium-ion Batteries

Electrochemical energy storage technologies such as rechargeable batteries show considerable progress due to their high efficiency, flexible power, long life cycle, and low maintenance. Graphite is a common anode material used in lithium-ion batteries. However, there are several shortcomings in graphite anode material, one of which is poor structural stability. Therefore, hard carbon is the most promising candidate for lithium-ion battery anodes due to its high storage capacity, low working potential, and cycle stability. This research utilizes teak sawdust waste as a hard carbon battery anode. They were approached by the carbonization method at temperatures of 350°C and 450°C. In general, X-Ray Diffraction (XRD) results show an amorphous structure of carbon atoms. The morphological structure known through the Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) test shows a fiber shape. The mass percent of carbon at a temperature of 450°C was higher than at a temperature of 350°C, which was 67.93%. Then the battery performance test was carried out with the highest discharge capacity value obtained at a temperature of 450°C at 191.56 mAh/g. Based on the results of this study, teak sawdust waste material has the potential as an anode for rechargeable batteries and can prevent environmental pollution

Hydrazine and Urea Fueled-Solution Combustion Method for Bi2O3 Synthesis: Characterization of Physicochemical Properties and Photocatalytic Activity

Bismuth oxide synthesis using solution combustion method fuelled by hydrazine and urea has been conducted. This study aims to examine the effect of the applied fuels, urea and hydrazine, on product characteristics and photocatalytic activity in degrading rhodamine B dye. Bismuth oxide synthesis was initiated by dissolving bismuth nitrate pentahydrate (Bi(NO3)3.5H2O) in a nitric acid solvent. Fuel was added and then stirred. The solution formed was heated at 300 ºC for 8 hours. The product obtained was then calcined at 700 ºC for 4 hours. Bismuth oxide synthesized with urea (BO1) and hydrazine (BO2) as fuels both obtained form of yellow powder. The formation of bismuth oxide is indicated by the vibrations of the Bi–O–Bi and Bi–O groups and the crystal structure of a-Bi2O3 in both products. Photocatalytic activity test showed that BO1 has a photocatalyst activity in degrading rhodamine B higher than that of BO2 with constant values of  3.83×10-5 s-1 and 3.43×10-5 s-1, respectively. The high photocatalytic activity can be examined through several factors, such as: band gap values, crystal structure, morphology, and surface area, acquired as a result of the use of different fuels in the synthesis process. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

PEMBUATAN KOMPOSIT CARBON NANOTUBE-POLYVINYL ALCOHOL (CNT-PVA) SERTA EVALUASI SIFAT MEKANIKNYA

Perkembangan teknologi nanomaterial mendukung teknologi komposit. Komposit yang menggunakannanomaterial menghasilkan sifat mekanik yang lebih baik daripada komposit biasa. Komposit carbon nanotubes(CNT) berpotensi memiliki kekuatan tarik yang tinggi oleh adanya struktur tabung nanonya yang baik sebagaimatrik. Komposit CNT-PVA telah dibuat dengan metode pelarutan. Polyvinyl alcohol (PVA) dilarutkan dalam airbertemperatur 80°C, selanjutnya material CNT ditambahkan ke dalam larutan tersebut dengan variasi fraksi massaCNT terhadap PVA sebesar 10%, 20% dan 30%. Komposit CNT-PVA terbentuk setelah dikeringkan padatemperatur 80°C. Selanjutnya sifat mekanik komposit dikarakterisasi dengan uji kekuatan tarik. Hasil ujimenunjukkan bahwa komposit CNT-PVA dengan fraksi massa 20% CNT terhadap PVA menghasilkan modulusYoung yang paling besar yaitu 137,71MPa. Ketebalan komposit 0,94 mm yang dibangun oleh tiga lapis tipiskomposit CNT-PVA menghasilkan peningkatan modulus Young hingga 107,30%

Synthesis and Characterization of Material LiNi0.8Co0.15Al0.05O2 Using One-Step Co-Precipitation Method for Li-Ion Batteries

Li-ion battery is an energy storage device which could be applied as power source for electronic devices. The capacity of a battery is determined by the cathode material. Over this last decade, high nickel content cathode material is applied for electric vehicular technology. This study aims to synthesize a nickel-rich cathode material, LiNi0.8Co0.15Al0.05O2 (NCA) via one-step co-precipitation and study its characteristics. The Ni, Co and Al metal ion conversion during co-precipitation were analyzed using Atomic Adsorption Spectroscopy (AAS). Based on X-Ray diffraction analysis, NCA sample exhibited hexagonal-layered structure with high crystallinity. Based on Scherrer equation, the mean crystallite diameter of NCA sample is 40 nm. Scanning electron microscope (SEM) showed micron-sized homogenous particles with smooth surface. The final composition of Ni, Co and Al metal were confirmed using XRF. The capacity of the battery was determined using galvanostic test method with voltage range of 2.7-4.25 V using graphite as the counter anode. The initial specific discharge capacity of NCA is 60 mAh/g while the capacity loss per cycle is 1%

Pembuatan Komposit Carbon Nanotube-polyvinyl Alcohol (Cnt-pva) Serta Evaluasi Sifat Mekaniknya

Perkembangan teknologi nanomaterial mendukung teknologi komposit. Komposit yang menggunakannanomaterial menghasilkan sifat mekanik yang lebih baik daripada komposit biasa. Komposit carbon nanotubes(CNT) berpotensi memiliki kekuatan tarik yang tinggi oleh adanya struktur tabung nanonya yang baik sebagaimatrik. Komposit CNT-PVA telah dibuat dengan metode pelarutan. Polyvinyl alcohol (PVA) dilarutkan dalam airbertemperatur 80°C, selanjutnya material CNT ditambahkan ke dalam larutan tersebut dengan variasi fraksi massaCNT terhadap PVA sebesar 10%, 20% dan 30%. Komposit CNT-PVA terbentuk setelah dikeringkan padatemperatur 80°C. Selanjutnya sifat mekanik komposit dikarakterisasi dengan uji kekuatan tarik. Hasil ujimenunjukkan bahwa komposit CNT-PVA dengan fraksi massa 20% CNT terhadap PVA menghasilkan modulusYoung yang paling besar yaitu 137,71MPa. Ketebalan komposit 0,94 mm yang dibangun oleh tiga lapis tipiskomposit CNT-PVA menghasilkan peningkatan modulus Young hingga 107,30%

Studying Impact of Different Precipitating Agents on Crystal Structure, Morphology and Photocatalytic Activity of Bismuth Oxide

Bismuth oxide (Bi2O3) is a well-studied photocatalyst for degradation of various environmental contaminants. In this research Bi2O3 has been synthesized by precipitation method using two different bases (NH4OH and NaOH). The samples thus obtained were then analyzed using FTIR, XRD, and SEM for surface functionalization, crystal structures and morphological differences, respectively. The Bi2O3 precipitated using NH4OH showed a flower like structure made up of individual plates having α-Bi2O3 crystal structure. The precipitate obtained using NaOH showed a honeycomb like flower structure with a mixture of both α-Bi2O3 and γ-Bi2O3 crystal structure. Degradation of methyl orange (MO) was used as a model system to test the photocatalytic activity of the bismuth oxide. The Bi2O3 synthesized using NH4OH showed superior photocatalytic degradation of methyl orange than the one synthesized using NaOH.