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"ABSTRAKPenggunaan berbagai produk titanium selalu mengalami peningkatan dari tahun ke tahun. Produk titanium yang paling sering digunakan adalah TiO2 sebagai pigmen warna putih dalam industri cat, industri makanan dan industri kosmetik. Indonesia mansih mengimpor berbagai produk titanium. Padahal di Indonesia banyak terdapat mineral ilmenite yang merupakan sumber utama titanium yang terdapat di alam. Penelitian ini dilakukan untuk mendapatkan TiO2 anatase dari Ilmenite Bangka. Residu kaya titanium didapatkan dari hasil leaching ilmenite Bangka dengan larutan asam klorida untuk melarutkan besi pada ilmenite. Data EDX menunjukkan bahwa kandungan besi berkurang pada residu hasil leaching. Digunakan H2O2 10% sebagai agen pengkoordinasi untuk meleaching titanium dari residu menjadi garam ammonium perokso titanat. Padatan perokso titanat didapatkan dengan memanaskan larutan garam ammonium perokso titanat. Data XRD menunjukkan terbentuknya TiO2 anatase setelah mengkalsinasi padatan tersebut pada suhu 600oC. Data EDX juga menunjukkan bahwa masih terdapat pengotor-pengotor seperti silikon (0,98%) dan besi (2,75%) pada TiO2 anatase yang didapatkan. Berbagai karakterisasi dilakukan pada TiO2 anatase seperti uv-vis spektroskopi, scanning electron microscopy dan UV Diffuse Reflectance Spectroscopy. TiO2 anatase dari ilmenite ini mempunyai nilai celah energi 3,08 eV. Uji fotokatalis dilakukan terhadap zat warna CongoRed dan dibandingkan dengan TiO2 komersial degussa P25. Persen degradasi oleh TiO2 anatase dari ilmenite ini sekitar 20%, sedangkan persen degradasi oleh degussa P25 mencapai nilai 92%.

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ABSTRACTThe use of titanium products have been increasing from year to year. TiO2 is one of titanium products which is often used as a white pigment in paint, food industry and cosmetics industries. Until now, Indonesia is stil importing various product of titanium even though Indonesia has many ilmenite source which are naturally the main source of titanium. This research was conducted to obtain TiO2 anatase from Bangka ilmenite. The hydrolyzed titania residue was prepared from Bangka ilmenite leached by hydrochloric acid solution to dissolve the iron in ilmenite. EDX data show that the iron content was reduced in hydrolyzed titania residue. The H2O2 (10%) was used as a coordination agent to leach titanium from the hydrolyzed titania residue to obtain ammonium perokso titanate. Peroxo titanate powder was obtained by evaporating the ammonium perokso titanate solution. XRD data show that TiO2 anatase was formed after calcining peroxo titanate powder at the temperature of 600oC. EDX data also show the anatase TiO2 obtained in this research had the impurities, such as silicon (0,98%) and iron (2,75%). Various studies such as X-ray diffraction, UV-vis spectroscopy, Scanning Electron Microscopy and UV Diffuse Reflectance Spectroscopy were conducted. The band gap of anatase TiO2 from extracted ilmenite is 3,08 eV. Photoreactivity was conducted againts the CongoRed dye and compared with the commercial TiO2, Degussa P-25. The degradation percentage of TiO2 from extracted ilmenite is 20% whereas degradation percentage of Degussa P25 is 92%."

"Diantara tiga struktur TiO₂, anatase TiO₂ telah mendapat banyak perhatian karena sifatnya yang menarik serta potensinya untuk dimanfaatkan dalam berbagai aplikasi. Berbagai aplikasi tersebut bergantung pada sifat transpor material ini. Beberapa penelitian terdahulu mengenai sifat transport anatase TiO₂ menunjukkan adanya kopling antara elektron dan fonon yang membentuk suatu kuasi partikel bernama polaron. Namun, belum ada penjelasan mengenai bagaimana keberadaan polaron pada anatase TiO₂ mempengaruhi sifat transpor terutama resistivitas. Oleh karena itu, kami melakukan studi teoretik terhadap sifat transport anatase TiO₂ yang dipengaruhi oleh kehadiran polaron. Kami menggunakan model Holstein, di mana menggunakan dua pita anatase TiO₂ yaitu pita konduksi dan pita valensi yang diselesaikan dalam kerangka Dynamical Mean Field Theory (DMFT) untuk menjelaskan interaksi antar elektron dan fonon. Kami menghitung densitas keadaan sistem dan nilai dari invers kuadrat dari densitas keadaan yang berkorespondensi pada potensial kimia, di mana nilai ini sebanding dengan nilai resistivitas, sebagai fungsi temperatur. Dengan menggunakan nilai densitas pembawa muatan seperti pada eksperimen, hasil perhitungan menunjukkan pada resistivitas turun seiring dengan pertambahan temperatur pada seluruh nilai densitas pembawa muatan. Hal ini menunjukkan bahwa model yang digunakan hanya baik dalam mendeskripsikan efek trapping namun kurang baik dalam menjelaskan efek hamburan.

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We present a theoretical study on the effects of electron-phonon interactions on the transport properties of anatase TiO₂. Temperature-dependent resistivity measurement on anatase TiO₂ thin film has shown that carrier concentrations and temperatures affect the resistivity of this material. At low carrier concentrations, a metal to insulator transition could be observed, while at high carrier concentrations this material only shows metal-like resistivity. In this study we aim to investigate the behavior of temperature-dependent resistivity at various carrier concentrations as revealed in the experimental study. We hypothesize that electron-phonon interactions with intermediate coupling constant govern the transport properties of this material. We construct Holstein model Hamiltonian incorporating both conduction and valence bands of anatase TiO₂ within parabolic dispersion approximation. We solve the model within the Dynamical Mean Field Theory (DMFT). We calculate the density of states of the system and the corresponding inverse of the square of the density of states at the chemical potential, which is approximately proportional to the resistivity, as a function of temperature. Using carrier concentration values taken as in the experimental data, the calculations show that only the trends of decreasing resistivity with increasing temperature is found in all carrier concentrations value. The results show that our model is good in the describing the trapping effects due to the electron-phonon interaction but the model is doing poorly in capturing the scattering effects."

"Perhitungan Density Functional Theory DFT digunakan untuk menginvestigasi sifat-sifat elektronik TiO2 pada fase anatase,baik yang murni maupun yang di dope dengan Ta. Hasil perhitungan menunjukan bahwa TiO2 merupakan bahan semikonduktor non feromagnetik. Interaksi elektron-elektron diikutsertakan melalui DFT U, sehingga hasil perhitungan lebih sesuai dengan data eksperimen. Sifat-sifat optis diteliti melalui perhitungan fungsi-fungsi dielektrik tanpa dan dengan melibatkan interaksi elektron-hole melalui persamaan Bethe Salpeter. Hasil perhitungan dengan DFT U dan DFT U BSE menunjukan adanya eksiton pada TiO2 murni. Penambahan Ta pada TiO2 menguatkan spektrum optis pada sekitar energy 4,3 eV dan hasil perhitungan yang telah didapat, dapat dikatakan konsisten dengan paper rujukan [Z. Yong et al].

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The Density Functional Theory DFT calculation is used to investigate the electronic properties of TiO2 in the anatase phase, either pure or dope with Ta. The results show that TiO2 is a non ferromagnetic semiconductor material. The interactions of electrons are included through DFT U, so the results of the calculations are more in line with the experimental data. The optical properties are examined through the calculation of dielectric functions without and by involving electron hole interactions via the Bethe Salpeter equation. The results of calculations with DFT U and DFT U BSE indicate the existence of an exciton in TiO2 pure. The addition of Ta to TiO2 amplifies the optical spectrum around 4.3 eV of energy and the calculated results can be said to be consistent with the reference paper Z. Yong et al."

"ABSTRAKPada penelitian ini dilaporkan investigasi mengenai efek dari eksposur faset kristal (001) TiO2 anatase terhadap aktivitas fotoelektrokatalitik dari fotoanoda yang terdiri dari film nanokomposit BiVO4/TiO2. Fotoanoda dibuat dengan mendeposisikan nanokomposit di atas permukaan kaca FTO melalui teknik doctor blade. Dalam penelitian ini, empat jenis morfologi TiO2 antase yaitu, nanospindel, nanocube, nanooctahedral, dan nanosheet disintesis melalui metode hidrotermal dengan penambahan directing agent yang berbeda. Selanjutnya, TiO2 hasil sintesis dikarakterisasi dengan menggunakan X-Ray Diffractometer (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmelt Tellers (BET), dan UV-Vis diffuse reflectance spectra (DRS). Berdasarkan hasil karakterisasi, puncak difraksi menunjukkan karakteristik untuk fase anatase murni dengan eksposure faset kristal (001) untuk nanospindel dan nanocube dan faset kristal (101) untuk nanocube dan nanooctahedral. Selain itu, respon fotoelektrokimia dari fotoanoda juga diukur menggunakan sistem 3 elektroda pada reaktor photocatalytic fuel cell (PFC) dan menghasilkan nilai densitas arus mencapai 0,0386 mA/cm2 untuk nanokomposit BiVO4/TiO2 nanosheet dan 0,0381 mA/cm2 untuk nanokomposit BiVO4/TiO2 nanospindle. Menggunakan sistem PFC ini, degradasi rhodamin B yang diperoleh adalah sebesar 23,15% untuk nanokomposit BiVO4/TiO2 nanosheet dan 30,58% untuk nanokomposit BiVO4/TiO2 nanospindle selama 3 jam reaksi.

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ABSTRACTThis work reports an investigation on the effect of exposing (001) crystal facet of anatase TiO2 to photoelectrocatalytic activity of photoanode composed of TiO2/BiVO4 nanocomposite film. Here, the photoanode was fabricated by depositing the nanocomposite on the surface of FTO via doctor blade technique. In this study, four different types of anatase TiO2 morphologies, i. e. nanospindle, nanocube, nanooctahedra, and nanosheet were synthesized via hydrothermal method in the presence of various directing agents. Furthermore, the as-prepared TiO2 was characterized using X-Ray Diffractometer (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmelt-Tellers (BET), and UV-Vis diffuse reflectance spectra (DRS). Based on the result, the diffraction peaks revealed characteristic for the pure anatase phase with exposure (001) crystal facet for nanospindle and nanosheet and (101) crystal facet for nanocube and nanooctahedra. Additionally, photoelectrochemical response of the photoanode was also evaluated using a three-electrode system on the photocatalytic fuel cell (PFC) reactor and exhibited a significantly high current density value of 0.0386 mA/cm2 and 0.0381 mA/cm2 for TiO2 nanosheet/BiVO4 and TiO2 nanospindle/BiVO4 nanocomposite. Using this PFC system, the degradation of rhodamine B were obtained 23.15% and 30.58% for TiO2 nanosheet/BiVO4 and TiO2 nanospindle/BiVO4 nanocomposite for 3 hours reaction time. "

"Dye-Sensitized Solar Cell (DSSC) merupakan sumber energi alternatif yang sangat menjanjikan. Salah satu komponen penting DSSC adalah fotoanoda yaitu berupa bahan TiO2 yang disensitasi dengan zat warna. Pada penelitian kali ini, TiO2 Nanorod telah berhasil disintesis dengan menggunakan metode hidrotermal menggunakan Ti(OBu)4 sebagai prekursor Ti dan dilanjutkan dengan perlakuan panas (kalsinasi) pada variasi suhu (tanpa kalsinasi, 500ºC, 700ºC, 800ºC, dan 950ºC). Berdasarkan hasil karakterisasi SEM-EDX, bentuk morfologi nanorod belum nampak pada sampel TiO2 (tanpa kalsinasi), untuk sampel TiO2 (dengan suhu kalsinasi 700ºC) sudah mulai nampak terbentuk morfologi nanorod tetapi belum sempurna dan untuk sampel TiO2 (dengan suhu kalsinasi 950ºC) sudah terbentuk morfologi nanorod secara jelas dengan diameter lubang rod yang bervariasi yaitu sebesar 223.8 nm, 277.8 nm, 322.0 nm, dan 326.3 nm. Hasil analisis FTIR menunjukkan bahwa pada suhu kalsinasi semakin tinggi maka puncak serapan pada daerah yang khas untuk gugus fungsi hidroksil semakin rendah nilai serapannya, mengindikasikan semakin berkurangnya keberadaan residu gugus OH bebas. Sedangkan, hasil dari analisis XRD didapatkan hasil bahwa sampel tanpa kalsinasi menunjukkan keberadaan fasa anatase dan rutile dengan ukuran kristalit sebesar 11.34 nm. Sampel TiO2 Nanorod dengan perlakuan panas pada suhu kalsinasi 500ºdidominasi oleh keberadaan fasa kristal rutile, memiliki ukuran kristalit sebesar 20.98 nm. Semakin besar suhu kalsinasi diamati semakin didominasi oleh fasa rutile, dan ukuran kristalitnya menjadi semakin besar, berturut-turut sampel TiO2 Nanorod (dengan suhu kalsinasi 700º, 800ºC dan 950ºC) sebesar 22.14 nm, 39.45 nm, 46.76 nm. Hasil karakterisasi dengan menggunakan Spektrofotometri UV-DRS didapatkan hasil semakin besar suhu kalsinasi maka nilai energi band gap semakin kecil. Nilai band gap yang dihasilkan berada pada rentang anatase dan rutile. TiO2 Nanorod (tanpa kalsinasi) memiliki nilai band gap sebesar 3.06 eV, sedangkan untuk TiO2 Nanorod (dengan suhu kalsinasi 500ºC, 700ºC, 800ºC dan 950ºC sebesar 3.05 eV, 3.04 eV, 3.03 eV, dan 3.03 eV.

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Dye-sensitized solar cell (DSSC) is a very promising source of alternative energy. One of the key components of the DSSC is photoanoda, which is associated with the TiO2 content. In this research, nanorod TiO2 has been successfully synthesized using the hydrothermal method, by using Ti(OBu)4 as a precursor of Ti, and followed by thermal treatment (calcination) at various temperature (without calcination, 500ºC, 700ºC, 800ºC, and 950ºC). Based on SEM-EDX characterization, TiO2 samples the sample (without calcination) showed no clear formation of nanorod morphology. In the other hand, the TiO2 sample which was heated at 700ºC, started showing the nanorod morphology and a clear nanorod morphology was observed in the TiO2 sample which has heated at 950ºC. The diameter of the rood produced was 223.8 nm, 277.8 nm, 322.0 nm, and 326.3 nm, respectively. The FTIR analysis showed that the peak absorption attributed to the OH group decreased when with more high temperature treatment exposed to the TiO2 samples. The XRD analysis of uncalcinated sample indicated the formation of slightly anatase and more predominantly by rutile, which has a crystallite size of 11.34 nm. It was observed that with more higher temperatures, TiO2 Nanorod samples were predominated by rutile crystal phase. In addition the higher calcination temperatures resulted bigger crystallite size these are the calcination temperature of 500ºC, 700ºC, 800ºC, and 950oC resulted crystallite size of 20.98 nm, 22.14 nm, 39.45 nm, and 46.76 nm, respectively. The characterization results using UV-DRS spectrophotometry showed that the greater the calcination temperature, the smaller the band gap energy value. The resulting band gap values are in the anatase and rutile ranges. TiO2 Nanorod (without calcination) has a band gap value of 3.06 eV, while for TiO2 Nanorod (with calcination temperatures of 500ºC, 700ºC, 800ºC and 950ºC of 3.05 eV, 3.04 eV, 3.03 eV and 3.03 eV."

"[ABSTRAKPeningkatan kesadaran akan ancaman polusi lingkungan mendorong pengembangan pengolahan limbah yang lebih efisien dan berkesinambungan. Material semikonduktor TiO2 merupakan material yang diharapkan memegang peranan penting dalam penyelesaian permasalahan polusi lingkungan melalui pemanfaatan energi matahari berbasis perangkat fotovoltaik termodifikasi. Sistem hibrid Dye Sensitized Solar Cell (DSSC)-katalisis merupakan salah satu pendekatan penyelesaian permasalahan limbah dikarenakan dapat mengoksidasi berbagai senyawa limbah serta pengaktifan dalam jangkauan panjang gelombang sinar tampak menyebabkan sistem ini menjadi lebih efisien.Pada penelitian ini, fabrikasi sistem hibrid DSSC-katalisis menggunakan TiO2 nanotube yang disintesis melalui teknik Rapid Breakdown Anodization pada beda potensial 15 V dalam elektrolit 0,15 M HClO4. Pengujian performa sistem hibrid DSSC-katalisis menggunakan simulasi limbah rhodamine B dalam air. Beberapa variasi yang dilakukan adalah zat warna yang digunakan, perbandingan luas daerah warna dan daerah katalisis, serta perbandingan komposisi campuran fase anatase-rutil dalam TiO2. Variasi ini dilakukan untuk mengetahui kondisi optimum device DSSC-katalisis dalam mendegradasi rhodamine B.TiO2 hasil sintesis dikalsinasi pada suhu 400°C selama 3 jam dan 2 jam serta 500°C selama 3 jam, lalu dikarakterisasi menggunakan XRD, UV Vis DRS, FTIR, FESEM, dan EDX. Hasil karakterisasi UV-Vis DRS menunjukkan band gap TiO2 hasil sintesis berkisar antara 3-3,5 eV. Sementara hasil uji FTIR yang menunjukkan ada puncak spesifik disekitar daerah 400-700 cm-1. Pada FESEM EDX, terlihat hasil yang cukup baik dalam bentuk bundle nanotube yang membuktikan bahwa teknik RBA dapat digunakan dalam proses sintesis TiO2 nanotube.TiO2 hasil sintesis digunakan untuk merangkai sistem hibrid DSSC-katalisis menggunakan rhodamine B dan ekstrak buah naga sebagai zat warnanya. Zona katalisis pada hibrid DSSC diuji aktivitas katalisisnya, dimana persen degradasi oleh sistem bersensitizer rhodamine B sebesar 65,22% dan ekstrak buah naga sebesar 34,78% dengan lama penyinaran masing-masing 60 menit. Hal ini menunjukkan bahwa dalam sistem ini, rhodamine B memberikan hasil yang lebih baik. Pengujian selanjutnya menggunakan sensitizer rhodamine B dengan variasi perbandingan luas zona warna dan zona katalisis sebesar 1:2, 1:1, dan 1:0,5 dan diperoleh persen degradasi berturut-turut 40,19%; 25,01% ; dan 9,59%. Dengan demikian perbandingan optimum pada variasi ini adalah luas zona warna dan katalis yang paling baik adalah 1:2. Pengujian ketiga menggunakan TiO2 dengan komposisi campuran fase kristal anatase rutil sebesar 100% anatase 0% rutil.

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ABSTRACTAn increasing concern on environmental pollution lead to development for more efficient and sustainable waste treatment. Titanium dioxide is expected to play an important role to solve the environmental pollution problem by using solar energy based on modified photovoltaic devices. Hybrid Dye Sensitized Solar Cell (DSSC) -catalysis system may become an efficient approach to solve the problem not only causes of the oxidizing power to degrade almost organic non biodegradable compounds in the waste but also the activation energy of this system still in visible light range. In this study, fabrication of hybrid DSSC - catalysis system used TiO2 nanotubes which was synthesized by Rapid Breakdown Anodization method, the potential difference was 15 V in 0.15 M HClO4. Degradating ability testing for hybrid DSSC ?catalysis system using simulated waste rhodamine B dispersed in water. Several variations has been done as kind of the dye used for the system, the wide comparison of dyes zone and catalytic zone, and composition of mixed crystalline phase ratio of anatase and rutile in TiO2 used. The purpose of the variation was to determine the optimum conditions for DSSC - catalysis device in degrading rhodamine B. TiO2 synthesized was calcined up to 400 ° C for 3 hours and 2 hours and 500°C for 3 hours. It was characterized using XRD, UV- Vis DRS, FTIR, FESEM, and EDX. UV- Vis DRS showed the band gap of samples between 3-3.5 eV. The result of FTIR measurements showed there was peak around the region 400-700 cm-1. FESEM EDX results showed very good shape of TiO2 nanotube bundle which proves that the RBA technique can be used in the synthesis process. Testing for determine the better sensitizer between rhodamine B and dragon fruit extract has been done. Based on the results of UV Vis measurements, percent degradation of rhodamine B system up to 65.22% and dragon fruit extract only 34.78%. Each of them exposure by visible light for 60 minutes. It indicates that in this system, rhodamine B sensitizer gives the better results. Further testing using sensitizer rhodamine B with a wide comparison of dye zone and catalytic zones by 1: 2, 1: 1 and 1: 0.5 and obtained percent of degradation respectively 40.19%; 25.01%; and 9.59%. Thus the optimum ratio in this variation is 1: 2. The third testing using the composition of the mixture TiO2 anatase-rutile crystalline phase 100% anatase 0% rutile, 92.88% anatase 7.12% rutile and 17.08% anatase 82.92% rutile with a percent of degradation for each sample were 66.80%, 81.01%, and 70.37%. The test results showed that the best phase in the system is the mixture of anatase 92.88% rutile 7.12%. Based on the three variations known that the system would work better if using rhodamine B as a;An increasing concern on environmental pollution lead to development for more efficient and sustainable waste treatment. Titanium dioxide is expected to play an important role to solve the environmental pollution problem by using solar energy based on modified photovoltaic devices. Hybrid Dye Sensitized Solar Cell (DSSC) -catalysis system may become an efficient approach to solve the problem not only causes of the oxidizing power to degrade almost organic non biodegradable compounds in the waste but also the activation energy of this system still in visible light range. In this study, fabrication of hybrid DSSC - catalysis system used TiO2 nanotubes which was synthesized by Rapid Breakdown Anodization method, the potential difference was 15 V in 0.15 M HClO4. Degradating ability testing for hybrid DSSC ?catalysis system using simulated waste rhodamine B dispersed in water. Several variations has been done as kind of the dye used for the system, the wide comparison of dyes zone and catalytic zone, and composition of mixed crystalline phase ratio of anatase and rutile in TiO2 used. The purpose of the variation was to determine the optimum conditions for DSSC - catalysis device in degrading rhodamine B. TiO2 synthesized was calcined up to 400 ° C for 3 hours and 2 hours and 500°C for 3 hours. It was characterized using XRD, UV- Vis DRS, FTIR, FESEM, and EDX. UV- Vis DRS showed the band gap of samples between 3-3.5 eV. The result of FTIR measurements showed there was peak around the region 400-700 cm-1. FESEM EDX results showed very good shape of TiO2 nanotube bundle which proves that the RBA technique can be used in the synthesis process. Testing for determine the better sensitizer between rhodamine B and dragon fruit extract has been done. Based on the results of UV Vis measurements, percent degradation of rhodamine B system up to 65.22% and dragon fruit extract only 34.78%. Each of them exposure by visible light for 60 minutes. It indicates that in this system, rhodamine B sensitizer gives the better results. Further testing using sensitizer rhodamine B with a wide comparison of dye zone and catalytic zones by 1: 2, 1: 1 and 1: 0.5 and obtained percent of degradation respectively 40.19%; 25.01%; and 9.59%. Thus the optimum ratio in this variation is 1: 2. The third testing using the composition of the mixture TiO2 anatase-rutile crystalline phase 100% anatase 0% rutile, 92.88% anatase 7.12% rutile and 17.08% anatase 82.92% rutile with a percent of degradation for each sample were 66.80%, 81.01%, and 70.37%. The test results showed that the best phase in the system is the mixture of anatase 92.88% rutile 7.12%. Based on the three variations known that the system would work better if using rhodamine B as a;An increasing concern on environmental pollution lead to development for more efficient and sustainable waste treatment. Titanium dioxide is expected to play an important role to solve the environmental pollution problem by using solar energy based on modified photovoltaic devices. Hybrid Dye Sensitized Solar Cell (DSSC) -catalysis system may become an efficient approach to solve the problem not only causes of the oxidizing power to degrade almost organic non biodegradable compounds in the waste but also the activation energy of this system still in visible light range. In this study, fabrication of hybrid DSSC - catalysis system used TiO2 nanotubes which was synthesized by Rapid Breakdown Anodization method, the potential difference was 15 V in 0.15 M HClO4. Degradating ability testing for hybrid DSSC ?catalysis system using simulated waste rhodamine B dispersed in water. Several variations has been done as kind of the dye used for the system, the wide comparison of dyes zone and catalytic zone, and composition of mixed crystalline phase ratio of anatase and rutile in TiO2 used. The purpose of the variation was to determine the optimum conditions for DSSC - catalysis device in degrading rhodamine B. TiO2 synthesized was calcined up to 400 ° C for 3 hours and 2 hours and 500°C for 3 hours. It was characterized using XRD, UV- Vis DRS, FTIR, FESEM, and EDX. UV- Vis DRS showed the band gap of samples between 3-3.5 eV. The result of FTIR measurements showed there was peak around the region 400-700 cm-1. FESEM EDX results showed very good shape of TiO2 nanotube bundle which proves that the RBA technique can be used in the synthesis process. Testing for determine the better sensitizer between rhodamine B and dragon fruit extract has been done. Based on the results of UV Vis measurements, percent degradation of rhodamine B system up to 65.22% and dragon fruit extract only 34.78%. Each of them exposure by visible light for 60 minutes. It indicates that in this system, rhodamine B sensitizer gives the better results. Further testing using sensitizer rhodamine B with a wide comparison of dye zone and catalytic zones by 1: 2, 1: 1 and 1: 0.5 and obtained percent of degradation respectively 40.19%; 25.01%; and 9.59%. Thus the optimum ratio in this variation is 1: 2. The third testing using the composition of the mixture TiO2 anatase-rutile crystalline phase 100% anatase 0% rutile, 92.88% anatase 7.12% rutile and 17.08% anatase 82.92% rutile with a percent of degradation for each sample were 66.80%, 81.01%, and 70.37%. The test results showed that the best phase in the system is the mixture of anatase 92.88% rutile 7.12%. Based on the three variations known that the system would work better if using rhodamine B as a, An increasing concern on environmental pollution lead to development for more efficient and sustainable waste treatment. Titanium dioxide is expected to play an important role to solve the environmental pollution problem by using solar energy based on modified photovoltaic devices. Hybrid Dye Sensitized Solar Cell (DSSC) -catalysis system may become an efficient approach to solve the problem not only causes of the oxidizing power to degrade almost organic non biodegradable compounds in the waste but also the activation energy of this system still in visible light range. In this study, fabrication of hybrid DSSC - catalysis system used TiO2 nanotubes which was synthesized by Rapid Breakdown Anodization method, the potential difference was 15 V in 0.15 M HClO4. Degradating ability testing for hybrid DSSC –catalysis system using simulated waste rhodamine B dispersed in water. Several variations has been done as kind of the dye used for the system, the wide comparison of dyes zone and catalytic zone, and composition of mixed crystalline phase ratio of anatase and rutile in TiO2 used. The purpose of the variation was to determine the optimum conditions for DSSC - catalysis device in degrading rhodamine B. TiO2 synthesized was calcined up to 400 ° C for 3 hours and 2 hours and 500°C for 3 hours. It was characterized using XRD, UV- Vis DRS, FTIR, FESEM, and EDX. UV- Vis DRS showed the band gap of samples between 3-3.5 eV. The result of FTIR measurements showed there was peak around the region 400-700 cm-1. FESEM EDX results showed very good shape of TiO2 nanotube bundle which proves that the RBA technique can be used in the synthesis process. Testing for determine the better sensitizer between rhodamine B and dragon fruit extract has been done. Based on the results of UV Vis measurements, percent degradation of rhodamine B system up to 65.22% and dragon fruit extract only 34.78%. Each of them exposure by visible light for 60 minutes. It indicates that in this system, rhodamine B sensitizer gives the better results. Further testing using sensitizer rhodamine B with a wide comparison of dye zone and catalytic zones by 1: 2, 1: 1 and 1: 0.5 and obtained percent of degradation respectively 40.19%; 25.01%; and 9.59%. Thus the optimum ratio in this variation is 1: 2. The third testing using the composition of the mixture TiO2 anatase-rutile crystalline phase 100% anatase 0% rutile, 92.88% anatase 7.12% rutile and 17.08% anatase 82.92% rutile with a percent of degradation for each sample were 66.80%, 81.01%, and 70.37%. The test results showed that the best phase in the system is the mixture of anatase 92.88% rutile 7.12%. Based on the three variations known that the system would work better if using rhodamine B as a]"

"Nanopartikel TiO2 anatase telah berhasil disintesis menggunakan prekursor titanium tetraisopropoxide dan katalis tetramethylammonium hydroxide dengan metode sol-gel yang kemudian dilanjutkan dengan proses hidrotermal dan kalsinasi. Perlakuan hidrotermal dilakukan dengan variasi temperatur 100, 125, dan 150oC, yang secara khusus ditujukan untuk menginvestigasi pengaruh temperatur proses hidrotermal terhadap peningkatan kristalinitas dan ukuran kristalit. Hasil yang didapatkan kemudian diaplikasikan untuk fabrikasi sel surya tersensitasi zat pewarna dye-sensitized solar cell, DSSC dengan melihat performa efisiensi konversi - dari DSSC yang di fabrikasi dengan menggunakan zat pensensitasi hasil ekstraksi anthocyanin dari pewarna alam buah senduduk Melastoma malabathricum L.. Metode karakterisasi material yang digunakan adalah X-ray Diffraction XRD, Scanning Electron Microscope SEM , Fourier transform infrared FTIR, ultraviolet-visible Spectroscopy UV-Vis, dan differential scanning calorimetry DSC, sementara pengujian performa untuk mengetahui efisiensi - dilakukan menggunakan Semiconductor Parameter Analyzer dengan menganalisis karakteristik kurva arus dan tegangan J-V. Hasil penelitian menunjukkan bahwa dengan meningkatnya temperatur proses hidrotermal, terdapat peningkatan kristalinitas dan ukuran kristalit yang cukup signifikan serta berbanding lurus. Semakin tinggi kristalinitas, ukuran kristalit juga mengalami peningkatan. Efisiensi DSSC yang didapatkan cukup menjanjikan dengan hasil perhitungan maksimal 5,69 untuk temperatur proses hidrotermal 150oC dan menggunakan zat pensensitasi dari anthocyanin yang diekstrak menggunakan etanol dan 20 wt. air suling. Hasil ekstraksi anthocyanin dari pewarna alam buah senduduk dalam penelitian ini memiliki potensi untuk digunakan sebagai zat pensensitasi pada DSSC.

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Anatase TiO2 nanoparticles have been successfully synthesized using Titanium Tetraisopropoxide as precursor and Tetramethylammonium hydroxide as catalyst through a sol gel method followed by hydrothermal treatment and calcination. Hydrothermal treatment was carried out at temperature variations of 100, 125, and 150oC, which is specifically aimed at investigating the effect of hydrothermal temperature on the crystallinity enhancement and crystallite size of the anatase TiO2 nanoparticles. The as synthesized TiO2 nanoparticles have been applied for dye sensitized solar cell DSSC, focused on the performance conversion efficiency of DSSC fabricated using sensitizer extracted from natural dye of Melastoma malabathricum L.

Characterization of the as synthesized materials was performed using X ray Diffraction XRD, Scanning Electron Microscope SEM , Fourier transform infrared FTIR, ultraviolet visible Spectroscopy UV Vis, and differential scanning calorimetry DSC, while the performance conversion efficiency was carried out using Semiconductor Parameter Analyzer through the characteristics of current versus voltage J V curve.

This results shows that increasing temperature of hydrothermal treatment results in significant crystallinity enhancement and an increase in crystallite size. The efficiency obtained is quite promising with maximum calculation of 5.69 for hydrothermal treatment temperature of 150oC sensitized using natural dye extracted with ethanol containing 20 wt. distilled water. This natural dye extracted from M. malabathricum L. has the potential to be used as sensitizer in DSSC device."