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Abstrak :
Nanokomposit TiO2/CuO dengan variasi rasio Cu/Ti disusun menggunakan metode sol-gel. Sampel komposit dikarakterisasi dengan X-Ray Diffraction, Energy Dispersive X-Ray Spectroscopy, Field Emission Scaning, Brunauer-Emmett-Teller, UV-Visible Diffuse Reflectance Spectroscopy dan Electronic Spin Resonance Spectroscopy. Methylene blue digunakan sebagai model pewarna tekstil untuk mengevaluasi fotokatalitik, sonokatalitik dan fotosonokatalitik. Difraksi sinar-X dan dispersif energi analisis X-ray menegaskan bahwa hanya struktur monoklinik CuO dan struktur anatase TiO2 yang muncul di nanokomposit TiO2/CuO. Degradasi methylene blue menunjukkan bahwa penggabungan CuO di nanokomposit TiO2/CuO menunjukkan aktivitas fotokatalitik yang cukup tinggi, dan energi cahaya yang dapat dimanfaatkan lebih banyak dibandingkan TiO2 murni. Selain itu, degradasi methylene blue juga diselidiki menggunakan sistem sonokatalisis dan sistem fotosonokatalisis. Hasil penelitian menunjukkan bahwa semua data eksperimen mengikuti model pseudo-first order tapi laju konstanta fotosonokatalisis lebih tinggi dari proses fotokatalisis dan sonokatalisis individu masing-masing. Selain itu, kegiatan fotokatalitik, sonokatalitik dan fotosonokatalitik akan berkaitan dengan sifat struktural dan optik sampel. Mekanisme kegiatan katalitik akan dibahas.

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TiO2/CuO nanocomposite with different Cu/Ti ratios were prepared using sol-gel method. The obtained composite samples were characterized with X-Ray Diffraction, Energy Dispersive X-Ray Spectroscopy, Field Emission Scaning, Brunauer-Emmett-Teller, UV-Visible Diffuse Reflectance Spectroscopy and Electronic Spin Resonance Spectroscopy. Methylene blue was used as a model of textile dye to evaluate their photocatalytic, sonocatalytic and photosonocatalytic activities. X-ray diffraction and energy dispersive X-ray analysis confirmed that only monoclinic CuO and anatase TiO2 structures are present in TiO2/CuO nanocomposites. The degradation of methylene blue indicated that the incorporation of CuO in TiO2/CuO nanocomposite exhibited an appreciable higher photocatalytic activity, and more light energy could be utilized than pure TiO2. In addition, the degradation of methylene blue was also investigated using sonocatalysis and photosonocatalysis systems. The results showed that all experimental data followed the pseudo-first order model but the rate constant of the sonophotocatalysis is higher than the respective individual photocatalysis and sonocatalysis process. Furthermore, the photocatalytic, sonocatalytic and photosonocatalytic activities will be related to their structural and optical properties. The mechanism of catalytic activities will be discussed.

Abstrak :
Metode hidrotermal telah diterapkan dalam pembuatan katalis nanokomposit Ag/CeO2 dengan tiga variasi rasio molar katalis nanopartikel CeO2 dan penambahan graphene pada nanokomposit dengan variasi tiga persen berat (wt.%). Kotoran dan fase lain dalam sampel tidak ditemukan dalam pengukuran Difraksi sinar-X (XRD) dan fluoresensi sinar-X (XRF). Keberadaan graphene dikonfirmasi oleh pengukuran Thermal Gravimetric Analysis (TGA) dan Raman Spectroscopy. Luas permukaan spesifik nanokomposit terbesar diperoleh untuk rasio molar CeO2 1:2 dan peningkatan 10wt.% pada graphene berdasarkan hasil pengukuran BET. Tiga jenis proses katalitik yang digunakan untuk mendegradasi Methylene Blue (MB), yaitu sonocatalytic (paparan gelombang ultrasonik), fotokatalitik (paparan sinar tampak dan ultraviolet), dan kombinasi keduanya (sonophotocatalytic). Degradasi maksimum MB diperoleh untuk variasi rasio molar 1:2 dengan 5 wt.% graphene untuk dosis 0,5 g/L dengan konsentrasi MB 20 mg/L pada pH larutan 13 untuk ketiganya. jenis proses katalitik. Mekanisme degradasi maksimum MB dalam proses sonofotokatalitik untuk katalis nanokomposit graphene Ag/CeO2/5 wt.% adalah kontribusi kekosongan oksigen, luas permukaan spesifik, adanya resonansi plasmon permukaan (SPR) dan situs aktif. Spesies aktif lubang yang berperan dalam proses katalitik yang melibatkan cahaya yaitu proses fotokatalitik dan sonofotokatalitik, sedangkan radikal hidroksil merupakan spesies yang berperan aktif dalam proses sonokatalitik.
The hydrothermal method has been applied in the manufacture of Ag/CeO2 nanocomposite catalysts with three variations of the molar ratio of the CeO2 nanoparticle catalyst and the addition of graphene to the nanocomposite with a variation of three percent by weight (wt.%). Impurities and other phases in the sample were not found in X-ray diffraction (XRD) and X-ray fluorescence (XRF) measurements. The existence of graphene was confirmed by Thermal Gravimetric Analysis (TGA) and Raman Spectroscopy measurements. The largest specific surface area of ​​nanocomposite was obtained for CeO2 1:2 molar ratio and 10wt.% increase in graphene based on BET measurement results. Three types of catalytic processes are used to degrade Methylene Blue (MB), namely sonocatalytic (exposure to ultrasonic waves), photocatalytic (exposure to visible and ultraviolet light), and a combination of both (sonophotocatalytic). The maximum degradation of MB was obtained for a variation of the molar ratio of 1:2 with 5 wt.% graphene for a dose of 0.5 g/L with a concentration of MB 20 mg/L at a solution pH of 13 for all three. type of catalytic process. The maximum degradation mechanism of MB in the sonophotocatalytic process for Ag/CeO2/5 wt.% graphene nanocomposite catalyst is the contribution of oxygen vacancies, specific surface area, presence of surface plasmon resonance (SPR) and active sites. Active species of holes that play a role in catalytic processes involving light are photocatalytic and sonophotocatalytic processes, while hydroxyl radicals are species that play an active role in sonocatalytic processes.

Abstrak :
Nanokomposit MnFe2O4/NGP dengan variasi 5, 10, dan 15 wt.% digunakan untuk sebagai katalis untuk mendegradasi methylene blue pada proses fotokatalitk dan sonokatalitik. MnFe2O4 dan MnFe2O4/NGP 5, 10, 15 wt.% disintesis dengan menggunakan metode hydrothermal. Impuritas dan fase lain tidak ditemukan pada pengukuran x-ray diffraction (XRD) dan x-ray fluorescence (XRF). Keberadaan NGP terkonfirmasi dari pengukuran XRD, thermogravimetric analysis (TGA), spektroskopi Raman, dan x-ray photoelectron spectroscopy (XPS). Penambahan luas sampel spesifik seiring bertambahnya NGP dikonfirmasi melalui pengukuran Brunauer-Emmet Teller (BET). Morfologi dari MnFe2O4 yang menyerupai persegi dan cenderung berkumpul didapat dari pengukuran transmission electron microscopy (TEM). Katalis memiliki kemampuan degradasi yang lebih baik pada proses photocatalytic dengan cahaya tampak dibanding cahaya UV. Kondisi sistem terbaik dari katalis untuk mendegradasi methylene blue adalah pada dosis katalis 0.2 g/L, konsentrasi H2O2 8 mL, dan pH 13. Penambahan NGP pada MnFe2O4 terbukti meningkatkan kemampuan degradasi methylene blue. Katalis juga terbukti memiliki stabilitas yang tinggi setelah digunakan sebanyak lima kali. Spesies aktif dari katalis pada proses fotokatalitik dan sonokatalitik adalah hidroksil radikal. ......MnFe2O4/NGP nanocomposites with variations of 5, 10, and 15 wt.% were used as catalysts to degrade methylene blue in the photocatalytic and sonocatalytic processes. MnFe2O4 and MnFe2O4/NGP 5, 10, 15 wt.% were synthesized using the hydrothermal method. Impurities and other phases were not found in x-ray diffraction (XRD) and x-ray fluorescence (XRF) measurements. The presence of NGP was confirmed by XRD measurements, thermogravimetric analysis (TGA), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS). The increase in specific sample area as NGP increases was confirmed by Brunauer-Emmet Teller (BET) measurements. The morphology of MnFe2O4 which resembles a square and tends to congregate was obtained from transmission electron microscopy (TEM) measurements. The catalyst has better degradation ability in photocatalytic processes with visible light than UV light. The best system conditions for the catalyst to degrade methylene blue were at a catalyst dose of 0.2 g / L, 8 mL H2O2 concentration, and a pH of 13. The addition of NGP to MnFe2O4 was proven to increase the degradation ability of methylene blue. The catalyst has also been shown to have high stability after being used five times. The active species of catalyst in photocatalytic and sonocatalytic processes are hydroxyl radicals