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"Pada penelitian ini, sintesis nanopartikel ZnO, Co2SnO4, dan nanokomposit ZnO/Co2SnO4 dilakukan secara green synthesis menggunakan ekstrak daun talas (Colocasia esculenta L. Schott) dalam sistem dua fasa (n-heksana – air). Kandungan metabolit sekunder yang terdapat pada ekstrak daun talas seperti alkaloid dan saponin akan berperan sebagai sumber basa lemah dan capping agent dalam proses sintesis. Selanjutnya, hasil sintesis akan dikarakterisasi dengan menggunakan Spektrofotometer UV-Vis, Spektrofotometer UV-Vis DRS, Spektroskopi FTIR, X-Ray Diffraction (XRD), dan Transmission Electron Microscopy (TEM). Berdasarkan hasil karakterisasi dengan spektrofotometer UV-Vis DRS didapatkan nilai band gap energy untuk nanopartikel ZnO, Co2SnO4, dan nanokomposit ZnO/Co2SnO4 masing-masing sebesar 3,08 eV, 1,6 eV, dan 2,44 eV. Nanokomposit ZnO/Co2SnO4 diuji aktivitas fotokatalitiknya terhadap malasit hijau. Berdasarkan hasil penelitian, uji aktivitas fotokatalitik nanokomposit ZnO/Co2SnO4 memiliki persen degradasi tertinggi pada kondisi optimum dengan berat sebesar 12 mg pada 5,0 x 10-6 M malasit hijau selama 120 menit di bawah sinar tampak, yaitu sebesar 92,63%.

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In this research, synthesis of ZnO, Co2SnO4 nanoparticles, and ZnO/Co2SnO4 nanocomposites were prepared by green synthesis using taro (Colocasia esculenta L.Schott) leaf extract in a two phase system (n-hexane – water). The content of secondary metabolites found in taro leaf extract such as alkaloid and saponin were roled as a source of weak base and capping agent in the synthesis process. Furthermore, the synthesis results were characterized by UV-Vis spectrophotometer, UV-Vis DRS spectrophotometer, FTIR spectroscopy, X-Ray Diffraction, and Transmission Electron Microscopy. UV-Vis DRS spectrophotometer characterization shows that band gap energy of ZnO, Co2SnO4 nanoparticles, and ZnO/Co2SnO4 nanocomposites were 3,08 eV, 1,6 eV, and 2,44 eV, respectively. ZnO/Co2SnO4 nanocomposites was applied for its photocatalytic activity to malachite green. Based on research results, the photocatalytic activity test of ZnO/Co2SnO4 nanocomposites had the highest degradation percentage of malachite green reached in the optimum condition of 12 mg mass catalyst and 5,0 x 10-6 M of malachite green concentration for 120 minutes under visible light, which was 92,63%."

"Dalam penelitian ini nanopartikel Bi2O3, nanopartikel Fe2O3, dan nanobimetal oksida BiFeO3 telah berhasil disintesis menggunakan metode green synthesis dengan ekstrak daun okra. Kandungan metabolit sekunder yang terdapat dalam ekstrak daun okra seperti alkaloid digunakan sebagai agen penghidrolisa (sumber basa lemah -OH), sedangkan saponin dan flavonoid digunakan sebagai agen penstabil (capping agent). Hasil sintesis nanobimetal oksida BiFeO3 selanjutnya dikarakterisasi menggunakan UV-Vis RS, FTIR, XRD, SEM, dan TEM. Hasil karakterisasi TEM dari nanobimetal oksida BiFeO3 menunjukkan morfologi spherical dan cenderung beraglomerasi. Hasil karakterisasi TEM dari nanobimetal oksida BiFeO3 memiliki struktur kristal rhombhohedral dengan rata-rata ukuran kristal sebesar 14, 55 nm. Selanjutnya hasil karakterisasi UV-Vis DRS dari nanopartikel Bi2O3, nanopartikel Fe2O3, dan nanobimetal oksida BiFeO3 memiliki nilai energi bandgap berturut-turut 2,87 eV, 2,11 eV, dan 2,00 eV. Aktivitas fotokatalitik nanobimetal oksida BiFeO3 dalam mendegradasi methylene blue lebih baik dibandingkan dengan nanopartikel Bi2O3 dan nanopartikel Fe2O3 dengan persen degradasi berturut0turut sebesar 94,04 %, 67,11 %, dan 80,44 %. Kinetika fotodegradasi terhadap methylene blue menggunakan fotokatalis BiFeO3 mengikuti kinetika reaksi orde pseudo 1.

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In this research, Bi2O3 nanoparticles, Fe2O3 nanoparticles, and BiFeO3 nanobimetallic oxide have been successfully synthesized using green synthesis method with okra leaf extract. The content of secondary metabolites contained in okra leaf extracts such as alkaloids is used as a hydrolyzing agent (weak base source -OH), while saponins and flavonoids are used as stabilizing agents (capping agents). The results of the synthesis of BiFeO3 nanobimetallic oxide were then characterized using UV-Vis RS, FTIR, XRD, SEM, and TEM. The results of TEM characterization of BiFeO3 nanobimetallic oxide show spherical morphology and tend to agglomerate. The results of TEM characterization of BiFeO3 nanobimetallic oxide have a rhombhohedral crystal structure with an average crystal size of 14.55 nm. Furthermore, the results of UV-Vis DRS characterization from Bi2O3 nanoparticles, Fe2O3 nanoparticles, and BiFeO3 nanobimetallic oxide have bandgap energy values respectively 2.87 eV, 2.11 eV and 2.00 eV. The photocatalytic activity of BiFeO3 nanobimetallic oxide in degrading methylene blue is better than that of Bi2O3 nanoparticles and Fe2O3 nanoparticles with percent degradation of 94.04%, 67.11%, and 80.44%, respectively. The kinetics of photodegradation against methylene blue using BiFeO3 photocatalysts follow the kinetics of first-order pseudo reaction."

"Pada penelitian ini, sintesis nanokomposit ZnO/CeMnO₃ dilakukan dengan metode green synthesis menggunakan ekstrak daun bayam raja (Amaranthus viridis). Metabolit sekunder pada ekstrak digunakan sebagai basa lemah dan capping agent dalam proses sintesis nanokomposit. Untuk mengidentifikasi sifat optik dan struktural nanopartikel serta nanokomposit, dilakukan dikarakterisasi dengan instrumen UV-Vis DRS, FTIR, XRD, Photoluminescence, SEM-EDX, dan HRTEM. Nanokomposit ZnO/CeMnO₃ menunjukkan nilai band gap yang menurun dibanding ZnO, yaitu pada 2,68 eV. Selain itu, karakterisasi HRTEM mengkonfirmasi terbentuknya ZnO/CeMnO₃ heterojunction dengan d spacing ZnO (110) = 0,162 nm dan d spacing CeMnO₃ = 0,31 nm. Ukuran partikel rata-rata ZnO/CeMnO₃ adalah 7,46 nm. Aktivitas fotokatalitik nanokomposit ZnO/CeMnO₃ diuji untuk mendegradasi larutan malasit hijau di bawah sinar tampak selama 120 menit serta dibandingkan dengan aktivitas fotokatalitik nanopartikel ZnO dan CeMnO₃. Persentase fotodegradasi malasit hijau oleh ZnO/CeMnO₃, CeMnO₃, dan ZnO masing-masing bernilai 92,69%; 69,46%; dan 37,5%. Kinetika reaksi fotodegradasi nanokomposit ZnO/CeMnO₃ mengikuti model orde satu semu dengan konstanta laju senilai 1,031 x 10^-2 min^-1. Peningkatan aktivitas fotokatalitik nanokomposit ZnO/CeMnO₃ disebabkan karena adanya penurunan bandgap ZnO dan rendahnya laju fotorekombinasi electron-hole yang masing-masing dibuktikan oleh analisis spektroskopi UV-Vis DRS dan photoluminescence.

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In this study, ZnO/CeMnO₃ nanocomposites were synthesized using green synthesis method using green amaranth leaf extract (Amaranthus viridis). The secondary metabolites present in the extract were utilized as a weak base and capping agent during the synthesis processes. To identify the optical and structural properties of the synthesized nanoparticles and nanocomposites, characterization was performed using UV-DRS, FTIR, XRD, Photoluminescence, SEM-EDX, and HRTEM instruments. The synthesized ZnO/CeMnO₃ nanocomposite showed a decreased band gap value compared to ZnO, at 2,68 eV. Additionally, XRD and HRTEM characterization confirmed the formation of the ZnO/CeMnO₃ composite on a nanometer scale with the average particle size at 7,46 nm. The photocatalytic activity of the ZnO/CeMnO₃ nanocomposite was tested by degrading a malachite green solution under visible light for 120 minutes and compared with the photocatalytic activity of ZnO and CeMnO3 nanoparticles. The percentages of malachite green photodegradation by ZnO/CeMnO₃, CeMnO₃, and ZnO were 92,69%; 69,46%; and 37,5%, respectively. The photodegradation reaction kinetics of the ZnO/CeMnO₃ nanocomposite were also determined to follow a pseudo-first-order model with a rate constant of 1.031 x 10^-2 min^-1. The increase in photocatalytic activity of the ZnO/CeMnO₃ nanocomposite is due to a decrease in the bandgap and a low rate of electron-hole photorecombination which is proven by UV-Vis DRS and photoluminescence analysis respectively."