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All Journal Metalurgi Makara Journal of Technology

Akhmad Herman Yuwono

Faculty of Engineering Universitas Indonesia

Author-ID : 426772

Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology Mechanical Engineering

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Articles

FABRIKASI NANOROD SENG OKSIDA (ZnO) MENGGUNAKAN METODE SOL-GEL DENGAN VARIASI KONSENTRASI POLYETHYLENE GLYCOL DAN WAKTU TUNDA EVAPORASI AMONIA Yuwono, Akhmad Herman
Metalurgi Vol 26, No 2 (2011): Metalurgi Vol.26 No.2 Agustus 2011
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Seng oksida (ZnO) adalah salah satu material semikonduktor yang banyak digunakan dalam aplikasi katalitik, elektronik dan optoelektronik. Pada penelitian ini, ZnO nanorods telah berhasil disintesis menggunakan metode sol-gel dengan campuran (Zn(NO3 ) 2 .4H2 O), NH4 OH, dan polyethylene glycol (PEG). Variasi pada konsentrasi PEG dan penahanan laju evaporasi amoniak pada larutan telah dilakukan dan nanorod ZnO yang dihasilkan dikarakterisasi dengan XRD dan SEM untuk menginvestigasi perbedaan diameter, morfologi dan tingkat nanokristalinitas nanorod ZnO. Penambahan PEG dari 1 hingga 3 gram pada larutan meningkatkan ukuran diameter rata-rata nanorods dari 157 menjadi 464 nm. Namun demikian tidak didapatkan adanya peningkatan ukuran nanokristalit ZnO di dalam struktur solid nanorod tersebut. Pada variasi waktu tunda evaporasi amonia selama 1 dan 2 jam, terjadi penurunan diameter nanorod menjadi 410 dan 328 nm, sebagai perbandingan terhadap diameter nanorod ZnO tanpa proses penundaan evaporasi ammonia yang mencapai 464 nm. Sebaliknya, besar kristalit di dalam struktur nanorod ZnO bertambah dari 121,49 menjadi 166,59 nm sejalan dengan penambahan waktu tunda evaporasi ammonia dari 1 hingga 2 jam, sebagai perbandingan terhadap ukuran kristalit nanorod ZnO tanpa proses penundaan evaporasi ammonia yang hanya mencapai 94,77 nm. AbstractZinc oxide (ZnO) is one of semiconductor materials which has been widely used for catalytic, electronic and optoelectronic applications. In the present research, ZnO nanorod has been successfully synthesized through a sol-gel method using (Zn(NO3)2.4H2O), NH4Keywords: ZnO nanorods, PEG concentration, Evaporation delay time, Crystallinity OH, and polyethylene glycol (PEG) precusrors. Variation in PEG concentration and ammonia evaporation delay time were performed and the resulting ZnO nanorods were characterized by XRD and SEM to investigate the difference in diameter, morphology and nanocrystallinity. It was revellead that the addition of PEG concentration from 1 to 3 grams has increased the average diameter of ZnO nanorods from 157 to 464 nm. However, there was no an increase in the crystallite size on those nanorod solid structures. The ammonia evaporation delay time from 1 to 2 hours has resulted in a deacrease in the average diameter of ZnO nanorods from 410 to 328 nm, in comparison to those of without evaporation delay time which can reach up to 464 nm. By contrast, the average crystallite size of ZnO phase in the nanorod structures has increased from 121.49 to 166.59 nm when the evaporation delay time was prolonged from 1 to 2 hours, as compared to those of without evaporation delay time which can only reach 94.77 nm in size.

STUDI PERBANDINGAN EFEK FOTOKATALISIS Fe2O3-TiO2 HASIL EKSTRAKSI ILMENIT BANGKA DAN P-25 DEGUSSA UNTUK APLIKASI PENGOLAHAN LIMBAH CAIR TPA CILOWONG[The Photocatalytic Effect of P-25 Degussa and Fe2O3-TiO2 Derived from Bangka- Indonesia Ilmenite Extraction for Waste Water Treatment of Leachate on the Landfill Cilowong] Lalasari, Latifa Hanum; Yuwono, Akhmad Herman; Firdiyono, Firdiyono; Andriyah, Lia; N, Elfi; Harjanto, Sri; Suharno, Bambang
Metalurgi Vol 27, No 3 (2012): Metalurgi Vol.27 No.3 Desember 2012
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

STUDI PERBANDINGAN EFEK FOTOKATALISIS Fe2O3-TiO2 HASIL EKSTRAKSI ILMENITBANGKA DAN P-25 DEGUSSA UNTUK APLIKASI PENGOLAHAN LIMBAH CAIR TPACILOWONG. Telah dilakukan penelitian penurunan kadar BOD5, COD, dan TDS dari lindi sampah tempatpembuangan akhir (TPA) Cilowong dengan menggunakan katalis Fe2O3-TiO2 dari hasil proses ekstraksi ilmenitBangka Indonesia dan TiO2 P-25 Degussa (komersial). Proses dilakukan dalam reaktor fotokatalitik berukuran30 x 15 x 20 cm dengan radiasi sinar UV 50 watt selama 90 menit pada temperatur kamar dan setiap 15 menitdiambil sampel untuk dilakukan analisa BOD5, COD, dan TDS. Variabel percobaan yang digunakan adalah rasiovolume (v/v) lindi/H2O sebesar 1/4; 1/8; 1/12; 1/16 dengan jumlah katalis yang digunakan masing-masingsebanyak 1 gram. Hasil penelitian pada rasio volume (v/v) lindi/H2O sebesar 1/16 menunjukkan penurunanBOD5, COD, TDS masing-masing sebesar 45; 90,43; 100 % untuk katalis Fe2O3-TiO2 dan sebesar 80,6; 75; 100% untuk TiO2 P-25 Degussa. Penelitian juga memberikan gambaran bahwa mineral Ilmenit Bangka Indonesiaberpotensi besar sebagai bahan baku dalam pembuatan katalis Fe2O3-TiO2. AbstractThe current work presents the results of investigation on the decreasing levels of BOD5, COD, TDS ofleachate on the landfill (TPA) Cilowong by using Fe2O3-TiO2 catalyst derived from the extraction process ofBangka Indonesia ilmenite as well as commercial TiO2 P-25 Degussa catalysts. The measurement wascarried out in a photocatalytic reactor of 30 x 15 x 20 cm equipped with a 50 watt UV radiation. The processwas performed for 90 minutes at room temperature, and the samples were taken every 15 min for BOD,COD, and TDS analyses. The ratio of leachate to H2O (%v) was varied as 1/4; 1/8; 1/12 and 1/16, with theamount of catalyst used was 1 gram. The result on ratio of leachate to H2O of 1/16 showed the decrease inBOD5, COD, TDS with the use of Fe2O3-TiO2 catalysts by 45; 90.43 and 100% for Fe2O3-TiO2 catalysts,while with the use of Degussa P-25 TiO2 catalysts the decrease in BOD5, COD, TDS reached by 80.6; 75 and100%, respectively. On the basis of findings, it is shown that Ilmenite Bangka Indonesia has great potentialas a raw material for synthesizing the Fe2O3-TiO2 catalysts.

FABRIKASI NANOTUBES TiO2 DENGAN TINGKAT NANOKRISTALINITAS TINGGI MELALUI PERLAKUAN KOMBINASI ANIL DAN PASCA-HIDROTERMAL UNTUK APLIKASI SEL SURYA TERSENSITISASI ZAT PEWARNA[Fabrication of Highly Nanocrystalline TiO2 Nanotubes Through a Combination of Pre-Annealing and Hydrothermal Treatment for Dye Sensitized Solar Cell Application] Ferdiansyah, Alfian; Yuwono, Akhmad Herman; Sofyan, Norifon; Kartini, Indriana; Pujianto, Togo Hadi; Munir, Badrul
Metalurgi Vol 27, No 2 (2012): Metalurgi Vol. 27 No. 2 Agustus 2012
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

FABRIKASI NANOTUBES TiO2 DENGAN TINGKAT NANOKRISTALINITAS TINGGI MELALUIPERLAKUAN KOMBINASI ANIL DAN PASCA-HIDROTERMAL UNTUK APLIKASI SEL SURYATERSENSITISASI ZAT PEWARNA. Dewasa ini struktur nanotubes telah mendapat perhatian yang sangatbesar karena memiliki rasio luas permukaan yang tinggi. Hal ini penting dalam aplikasinya sebagai elektroda selsurya tersensitasi zat pewarna (dye sensitized solar cell, DSSC). Pada penelitian ini telah difabrikasi nanotubesTiO2 melalui teknik hidrotermal standar dimana serbuk nano TiO2 P25 Degussa dilarutkan pada larutan alkalinsodium hidroksida berkonsentrasi tinggi di dalam otoklaf tersegel. Untuk meningkatkan nanokristalinitas,dilakukan sebuah modifikasi dimana proses anil konvensional dikombinasikan dengan pasca hidrotermal. Detailstruktur, morfologi dan kristalinitas diuji dengan XRD, spektroskopi Raman, SEM dan TEM, sedangkan sifatoptik dari nanotubes diinvestigasi dengan spektroskopi UV-Vis. Hasil investigasi menunjukkan bahwa denganmemberikan kombinasi anil konvensional dan pasca hidrotermal pada nanotubes, nanokristalinitas dapatditingkatkan secara signifikan dan pada saat yang sama integritas struktur rongga (hollow) tetap terjaga. Untuksampel nanotubes yang sebelumnya diberikan anil 150 °C, ukuran kristalit anatase bertambah dari 6,93 sampai7,82 nm setelah perlakuan pasca-hidrotermal 80-150 °C. Peningkatan nanokristalinitas lebih signifikanditunjukkan ketika temperatur anil dinaikkan sampai 300 °C kemudian dilanjutkan pasca-hidrotermal yang sama,menghasilkan peningkatan ukuran kristalit mulai dari 17,20 sampai 18,30 nm. Energi celah pita yang dihasilkannanotubes berbanding terbalik dengan ukurun kristalit, dimana nilai terendah sebesar 3,19 eV didapatkan dariukuran kristalit terbesar yaitu 18,30 nm. Nanotubes ini juga memberikan sirkuit tegangan terbuka pada divaisDSSC hasil fabrikasi sebesar 108 mV.AbstractFABRICATION OF HIGHLY NANOCRYSTALLINE TiO2 NANOTUBES THROUGH A COMBINATIONOF PRE-ANNEALING AND HYDROTHERMAL TREATMENT FOR DYE SENSITIZED SOLAR CELLAPPLICATION. In the recent years TiO2 nanotube structure has attracted a great attention due to its very highsurface area to volume ratio. This property plays an important role on the dye sensitized solar cell electrodesapplications. In this study, TiO2 nanotubes have been fabricated through hydrothermal technique by dissolvingDegussa P25 TiO2 nanopowder in a highly concentrated alkaline solution of sodium hydroxide into a sealedautoclave. In order to improve nanocrystallinty of TiO2 nanotubes structure, a modification was made bycombining conventional annealing process and hydrothermal post. Details of the structure, morphology andcrystallinity of products were analized by XRD, Raman spectroscopy, SEM and TEM, while the opticalproperties of the nanotubes was examined by UV-Vis spectroscopy. The investigation result showed thatenhancing nanocrystallinity while at the same time maintaining the integrity of the nanotube hollow structurecan be obtained by the combined process of conventional annealing and post-hydrothermal treatment. For thenanotube samples which have been previously annealed at 150 °C, the crystallite size of anatase TiO2 increasedfrom 6.93 to 7.82 nm after post-hydrothermal treatment of 80-150 °C. A more significant enhancement in the142 | Majalah Metalurgi, V 27.2.2012, ISSN 0216-3188/ hal 141-150nanocrystallinity can be achieved when the annealing temperature was raised to 300 ° C, followed by posthydrothermal.This resulted in the crystallite size of anatase TiO2 nanotubes increased from 17.20 to 18.30 nm.The band gap energy of resulting nanotubes is inversely proportional to crystallites size, where the lowest valueof 3.19 eV obtained from the largest crystallite size is 18.30. In the DSSC fabrication device, this nanotubes alsoshown the highest open-circuit voltage of 108 mV.

Pengaruh Waktu Deposisi dan Temperatur Substrat Terhadap Pembuatan Kaca Konduktif FTO (Fluorine doped Tin Oxide) [The Influence of Deposition Time and Substrate Temperature in Manufacturing Process of FTO (Fluorine doped Tin Oxide) Conductive Glass] Arini, Tri; Lalasari, Latifa Hanum; Yuwono, Akhmad Herman; Firdiyono, F; Andriyah, Lia; Subhan, Achmad
Metalurgi Vol 32, No 1 (2017): Metalurgi Vol. 32 No. 1 April 2017
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Manufacturing FTO (fluorine-doped tin oxide) is expected to replace ITO (indium tin oxide) because the process is simple and relatively low cost. Tin chloride precursor with fluorine doping is prepared via sol-gel method with a coating process with spray pyrolisis technique can be considered as a new breakthrough in DSSC device structures. This experiment uses the raw material tin (II) chloride hydrate (SnCl2.2H2O) as precursors and ammonium fluoride (NH4F) as a doping ratio of 6% wt with variation in temperatures of 250, 300, 350, 400 °C and time resistivities of 5, 20, 30 and 40 minutes. The results showed that the longer deposition time decreasing value of conductive glass resistivity. This condition would reduce the value of transmittance. High transmittance and low resistivity obtained on the variation of deposition time 5 minutes with a substrate temperature of 300 °C with a resistivity value of 3.16 x 10-4 Ω.cm and transmittance value of 86.74%AbstrakPembuatan FTO (flourine-doped tin oxide) ini diharapkan dapat menggantikan fungsi ITO (indium tin oxide) karena proses pembuatan yang sederhana dan biaya yang relatif rendah. Prekursor timah klorida dengan doping flourine yang dipreparasi melalui metode sol-gel dengan proses pelapisan dengan teknik spray pyrolisis dapat dipertimbangkan sebagai suatu terobosan baru di dalam struktur device sel surya tersensitasi zat pewarna. Percobaan ini menggunakan bahan baku timah (II) klorida hidrat (SnCl2.2H2O) sebagai prekursor dan amonium florida (NH4F) sebagai doping dengan rasio 6 %berat dengan variasi temperatur 250, 300, 350, 400 °C dan dengan variasi waktu 5, 20, 30, dan 40 menit. Hasil percobaan menunjukkan bahwa semakin lama waktu deposisi maka akan semakin kecil nilai resistivitas kaca konduktif. Namun semakin lama waktu deposisi akan mengurangi nilai transmitansi. Pada percobaan ini menghasilkan transmitansi tinggi dan resistivitas rendah diperoleh pada variasi waktu deposisi 5 menit dengan temperatur substrat 300 °C dengan nilai resitivitas 3,16 x 10-4 Ω.cm dan nilai transmitansi 86,74%.

Dye Sensitized Solar Cell with Conventionally Annealed and Post-Hydrothermally Treated Nanocrystalline Semiconductor Oxide TiO2 Derived from Sol-Gel Process Yuwono, Akhmad Herman; Munir, Badrul; Ferdiansyah, Alfian; Rahman, Arif; Handini, Wulandari
Makara Journal of Technology Vol. 14, No. 2
Publisher : UI Scholars Hub

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Dye-sensitized solar cell (DSSC) is one of the very promising alternative renewable energy sources to anticipate the declination in the fossil fuel reserves in the next few decades and to make use of the abundance of intensive sunlight energy in tropical countries like Indonesia. In the present study, TiO2 nanoparticles of different nanocrystallinity 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 post-hydrothermal treatments. The resulting nanoparticles were integrated into the DSSC prototype and sensitized with an organic dye made of the extract of red onion. The basic performance of the fabricated DSSC has been examined and correlated to the crystallite size and band gap energy of TiO2 nanoparticles. It was found that post-hydrothermally treated TiO2 nanoparticles derived from sol of 2.00 Rw, with the most enhanced nanocrystalline size of 12.46 nm and the lowest band gap energy of 3.48 eV, showed the highest open circuit voltage (Voc) of 69.33 mV.

Co-Authors Achmad Subhan Alfian Ferdiansyah Amalia Sholehah, Amalia Andriyah, Lia Anne Zulfia Arif Rahman Badrul Munir, Badrul Bambang Priyono Bambang Suharno Daniel Kurniawan Eny Kusrini Evvy Kartini firdiyono, F Firdiyono, Firdiyono Ghiska Ramahdita, Ghiska Heri Jodi, Heri Indriana Kartini johansyah johansyah John Wang Lalasari, Latifa Hanum Mario Marfelly, Mario N, Elfi Nofrijon Sofyan, Nofrijon Pujianto, Togo Hadi Sofyan, Norifon Sri Harjanto Tri Arini, Tri Wahid Muhamad Furkon Rahmatulloh, Wahid Muhamad Furkon Wulandari Handini Yu Zhang

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