Kurniawan, RizmahardianAshari (2013) Hybrid Biofuel Cell Based on Carbon Nanotube Covalently Attached Laccase Cathode and Polyaniline-Coated Carbon Nanotube-Supported Pt Bimetallic Anode. Magister thesis, Universitas Brawijaya.
Abstract
Latar belakang ekonomi dan permasalahan lingkungkungan telah memotivasi riset di bidang produksi energi. Dalam riset ini, biofuel sel hibrid dikembangkan untuk memenuhi kebutuhan tersebut. Biofuel sel tersebut terdiri dari katoda laccase amobil secara kovalen pada Carbon Nanotube (CNT-Laccase) dan anoda alloy platinum yang terdeposit pada Carbon Nanotube terkoating polianiline (PANICNT). CNT-Laccase dikarakterisasi dengan Fourier Transform Infrared Spectrophotometry (FTIR), Surface Electron Microscopy (SEM) dan Termogravimetry Analysis (TGA). Spektra FTIR menunjukkan bahwa struktur tersebut mengandung gugus fungsi seperti hidroksil, amin, dan amida. Gambar SEM menunjukkan imobilisasi tidak menghancurkan struktur tabung dari CNT, melainkan memicu terjadinya aggregasi. Analisis unsur menggunakan spektrometri Energy Disperse X-Ray (EDX) menunjukkan atom nitrogen dan oksigen terdistribusi pada struktur tersebut yang mengindikasikan adanya laccase pada CNT-Laccase. CNT-Laccase diketahui memiliki dua suhu penguraian yaitu pada 310ºC dan 670ºC, yaitu dekomposisi bagian laccase dan CNT dari CNT-Laccase. Immobilisasi Laccase mampu mengubah termostabilitas CNT. Immobilisasi juga mampu meningkatkan stabilitas aktivitas enzimatik laccase pada suhu tinggi dan pH netral. Laccase bebas kehilangan seluruh aktivitasnya pada suhu 65ºC, sedangkan CNT-Laccase masih mampu mempertahankan 57,12% dari aktivitasnya pada suhu 45ºC. Aktivitas CNT-Laccase pada pH 7 yaitu 7.04% dari aktivitasnya pada pH 5, yang lebih tinggi dibandingkan aktivitas laccase sebelum imobilisasi. CNT-Laccase tidak memiliki aktivitas elektroreduksi oksigen tanpa adanya penambahan ABTS (asam 2,2`-azino-bis(3-etilbenzotiazolin-6-sulfonat) sebagai mediator. ABTS dibutuhkan untuk menerima elektron dari elektroda dan mengantarkannya menuju gugus aktif laccase. Aktivitas elektroreduksi oksigen juga ditentukan oleh jenis dan komposisi polimer yang digunakan di elektroda. Berdasarkan penelitian yang dilakukan, nafion dapat mendorong aktivitas elektroreduksi oksigen yang lebih tinggi dibandingkan dengan polivinil alkohol (PVA). Arus listrik yang dihasilkan dengan menggunakan Nafion sebagai polimer dengan rasio 1:10 terhadap volume buffer adalah 1,31 mA/cm 2 . Hasil ini lebih tinggi dibandingkan menggunakan PVA, yaitu 1.01 mA/cm 2 . Peningkatan rasio polimer menjadi 1:2 dan 1:1 diketahui dapat menghambat aktivitas elektroreduksi oksigen. Pada bagian anoda, alloy seperti PtSn, Pt 3 Sn, Pt, and PtPb diuji aktivitas elektrooksidasi glukosa. Pembentukan alloy diketahui dengan adanya pergeseran pola difraksi sinar X dari Pt-fcc. Alloy-alloy tersebut dapat terdeposit pada permukaan PANICNT seperti yang terlihat pada foto Transmission Electron Microscopy (TEM). Alloy-alloy tersebut mampu mengoksidasi glukosa pada larutan basa dan netral dengan aktivitas yang berbeda-beda yang ditentukan oleh jenis logam sekunder. PtSn/PANICNT memiliki aktivitas tertinggi yang ditunjukkan dengan arus listrik yang tinggi dan sensitivitas yang tinggi terhadap kehadiran glukosa. Arus listrik yang dihasilkan sekitar 8 mA/cm 2 dan 4 mA/cm 2 pada larutan basa dan netral, secara berturut-turut. Sensitivitas PtSn/PANICNT tertinggi dicapai pada potentsial 0.0 V dan 0.1 V, yaitu sekitar 39.64 μAcm -2 mM -1 dan 39.54 μAcm -2 mM -1 , secara berturut-turut. Substitusi Sn menjadi Pb sebagai atom sekunder pada PtPb/PANICNT mampu menggeser elektrooksidasi glukosa pada potential yang lebih rendah. Hal ini ditunjukkan dengan sensitivitas tertinggi yang diperoleh pada potential -0,1 V, yaitu sebesar 40.33 μAcm -2 mM -1 .
English Abstract
Economic and environmental requirements have motivated research in energy generation. Here, hybrid biofuel cell have been developed to meet need. cathode composed of laccase immobilized on CNT (CNT-Laccase), while anode is Pt bimetallic alloy deposited on polyaniline-coated carbon nanotube (PANICNT). CNT-Laccase was characterized by Fourier Transform Infrared (FTIR) Spectrophotometry, Surface Electron Microscopy (SEM) and rmogravimetric Analysis (TGA). CNT-Laccase FTIR spectra showed that structure contain several functional groups, such as hydroxyl, amine and amide. SEM figures revealed that immobilization didn`t destroy tube structure of CNT, but it promoted aggregation. Elemental analysis of structure displayed oxygen and nitrogen atoms distribution indicating presence of Laccase. refore, FTIR and SEM reasserted successful immobilization. TGA reveal CNT-Laccase possesses two decomposition temperatures at 310ºC and 670ºC, that are related to decomposition of Laccase part and CNT part of CNT-Laccase, respectively. Laccase immobilization has changed CNT rmo stability. Immobilization also affected Laccase enzymatic activity where it boosts stability at high temperature and neutral pH. At temperature 65ºC, free Laccase completely loss its activity, while CNT-Laccase still retaining 57.12% of its activity at 45ºC. activity of CNT laccase at pH 7 was 7.04% of activity at pH 5 which was higher than that of free Laccase. CNT-Laccase was not able to perform oxygen electroreduction without addition ABTS (2,2`-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) as mediator. In our case, ABTS was needed to shuttle electrons from electrode to Laccase active site. Performance of oxygen electroreduction activity was also determined by type and composition of binding polymer. Nafion was able to provide better environment for oxygen electroreduction activity compare to polyvinyl alcohol (PVA). Current density resulted in using Nafion in ratio 1:10 to buffer volume was 1.31 mA/cm 2 , which was higher than that of PVA (1.01 mA/cm 2 ). Increasing binding polymer ratio into 1:2 and 1:1 undermined oxygen electroreduction activity. On anode side, alloy such as PtSn, Pt 3 Sn, Pt, and PtPb were tested to analyze ir activity toward glucose electrooxidation. formation of alloy was confirmed by shifted Pt fcc patterns on X-ray Diffraction (XRD) analysis. alloys were able to be deposited on PANICNT surface as confirmed by Transmission Electron Microscopy (TEM) images. All metal alloys were able to oxidize glucose in neutral and basic solution. activity is affected by presence of secondary atom. PtSn/PANICNT showed highest activity as reflected by highest current density and highest sensitivity. current density was about 8 mA/cm 2 and 4 mA/cm 2 at basic and neutral pH, respectively. highest sensitivity for PtSn/PANICNT was achieved at potential 0.0 V and 0.1 V, which were about 39.64 μAcm -2 mM -1 and 39.54 μAcm -2 mM -1 respectively. On o r hand, PtPb/PANICNT shifted glucose electrooxidation to lower potential as highest sensitivity (40.33 μAcm -2 mM -1 ) was achieved at -0.1 V.
| Item Type: | Thesis (Magister) |
|---|---|
| Identification Number: | TES/662.88/KUR/h/041305535 |
| Subjects: | 600 Technology (Applied sciences) > 662 Explosives of explosives, fuels, related products > 662.8 Other fuels |
| Divisions: | S2/S3 > Magister Matematika, Fakultas MIPA |
| Depositing User: | Endro Setyobudi |
| Date Deposited: | 13 Jan 2014 19:36 |
| Last Modified: | 13 Jan 2014 19:36 |
| URI: | http://repository.ub.ac.id/id/eprint/160116 |
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