Sintesis Carbon Quantum Dots (CQDs) Terdoping Ethylenediamine untuk Aplikasi Penyimpanan Hidrogen dalam Media Butanol

Apriliana, Herlani (2026) Sintesis Carbon Quantum Dots (CQDs) Terdoping Ethylenediamine untuk Aplikasi Penyimpanan Hidrogen dalam Media Butanol. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Krisis energi dan tuntutan ke energi terbarukan mendorong pengembangan teknologi penyimpanan hidrogen yang efisien pada tekanan rendah. Namun, adsorben karbon konvensional umumnya masih memerlukan tekanan tinggi atau temperatur kriogenik. Pendopingan nitrogen diketahui mampu meningkatkan interaksi H₂ dengan permukaan karbon, tetapi kajian pemanfaatan carbon quantum dots (CQDs) sebagai adsorben hidrogen masih terbatas. Penelitian ini bertujuan mensintesis dan mengevaluasi CQDs terdoping ethylenediamine (EDA) sebagai adsorben H₂, baik dalam bentuk powder maupun terdispersi dalam butanol sebagai sistem fuel-slurry. CQDs disintesis secara hidrotermal dari asam sitrat dengan variasi rasio CA:EDA (CQDs, CQDE1, CQDE2, dan CQDE3), kemudian dikeringkan menjadi serbuk dan sebagian didispersikan dalam butanol. Karakterisasi dilakukan menggunakan FTIR, XRD, FESEM dan Adsorpsi-Desorpsi N2 Isoterm. Uji adsorpsi H₂ dilakukan secara isotermal pada 298 K dan tekanan hingga sekitar 3 bar, kemudian dianalisis menggunakan model kinetika pseudo-orde dua, difusi intra-partikel, serta parameter termodinamika adsorpsi. Hasil menunjukkan bahwa peningkatan loading EDA meningkatkan kapasitas adsorpsi H₂ powder dari 0,1520 mmol g⁻¹ (CQDs) menjadi maksimum 3,8870 mmol g⁻¹ pada CQDE3 pada tekanan mendekati 1 bar, dengan efisiensi sekitar 3,9000 mmol g⁻¹ bar⁻¹. Secara kinetika, seluruh sampel mengikuti model pseudo-orde dua. Analisis termodinamika menghasilkan nilai ΔG negatif, yang mengindikasikan adsorpsi yang spontan. Pada sistem CQD@butanol, kapasitas per gram campuran lebih rendah akibat dominasi massa butanol (92,60 wt%). Namun, setelah normalisasi terhadap fraksi massa CQD (7,40 wt%), CQDE3@butanol menunjukkan kapasitas adsorpsi efektif sekitar 5,8380 mmol g⁻¹, lebih tinggi dibandingkan CQDE3 powder. Hasil ini menegaskan potensi CQDE3 sebagai adsorben hidrogen tekanan rendah dan komponen aktif dalam sistem penyimpanan berbasis fuel-slurry. Lalu, diperkuat juga berdasarkan nilai kalor Diesel/CQDE3@Butanol sebesar 10.9520 kkal/kg, sedikit lebih tinggi dibandingkan campuran Diesel@butanol tanpa penambahan CQDs yang
bernilai 10.8230 kkal/kg.
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The energy crisis and the growing demand for renewable energy have driven the development of efficient hydrogen storage technologies under low-pressure conditions. However, conventional carbon-based adsorbents generally require high pressure or cryogenic temperatures to achieve practical hydrogen storage capacities. Nitrogen doping is known to enhance the interaction between hydrogen molecules and carbon surfaces, yet studies on the use of carbon quantum dots (CQDs) as hydrogen adsorbents remain limited. This study aims to synthesize and evaluate ethylenediamine (EDA)-doped CQDs as hydrogen adsorbents, both in powder form and when dispersed in butanol as a fuel-slurry system. CQDs were synthesized hydrothermally from citric acid with different CA:EDA ratios (CQDs, CQDE1, CQDE2, and CQDE3). The resulting materials were dried into powders, and a portion was dispersed in butanol. Structural and surface characterizations were carried out using FTIR, XRD, FESEM, and N₂ adsorption–desorption isotherms. Hydrogen adsorption experiments were conducted isothermally at 298 K and pressures up to approximately 3 bar. The adsorption data were analyzed using the pseudo-second-order kinetic model, intraparticle diffusion model, and thermodynamic parameters of adsorption. The results show that increasing EDA loading significantly enhances the hydrogen adsorption capacity of CQDs, from 0.1520 mmol g⁻¹ for undoped CQDs to a maximum of 3.8870 mmol g⁻¹ for CQDE3 at pressures close to 1 bar, corresponding to an adsorption efficiency of approximately 3.9000 mmol g⁻¹ bar⁻¹. Kinetic analysis indicates that hydrogen adsorption on all samples follows the pseudo-second-order model, while thermodynamic analysis yields negative ΔG values, confirming the spontaneous nature of the adsorption process. For the CQD@butanol system, the hydrogen adsorption capacity per gram of mixture is lower due to the dominant mass fraction of butanol (92.60 wt%). However, after normalization to the CQD mass fraction (7.40 wt%), CQDE3@butanol exhibits an effective hydrogen adsorption capacity of approximately 5.8380 mmol g⁻¹, which is higher than that of CQDE3 in powder form. These results highlight the potential of CQDE3 as a lowpressure hydrogen adsorbent and as an active component in fuel-slurry-based hydrogen storage systems. This conclusion is further supported by the calorific value of Diesel/CQDE3@Butanol, which reaches 10,952.0 kcal kg⁻¹, slightly higher than that of the Diesel@butanol blend without CQDs (10,823.0 kcal kg⁻¹).

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Bahan Bakar Slurry, Ekstraksi Butanol, Etilendiamina, Penyimpanan Hidrogen, Titik kuantum karbon, Slurry Fuel, Butanol Extraction, Ethylenediamine, Hydrogen Storage. Carbon Quantum Dots
Subjects:	Q Science > QC Physics > QC162 Adsorption and absorption
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Chemistry > 47201-(S1) Undergraduate Thesis
Depositing User:	Herlani Apriliana
Date Deposited:	04 Feb 2026 07:55
Last Modified:	04 Feb 2026 07:55
URI:	http://repository.its.ac.id/id/eprint/132128

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