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The Effect of Carbon Nanotube Composite Addition on Biomass-Based Supercapacitor Widiatmoko, Pramujo; Devianto, Hary; Nurdin, Isdiriayani; Yandra, Ridho Eka
Journal of Engineering and Technological Sciences Vol 48, No 5 (2016)
Publisher : ITB Journal Publisher, LPPM ITB

Electric vehicles are set to become a most attractive alternative transportation mode due to their high efficiency and low emission. Electric vehicles require an efficient energy storage system, e.g. a supercapacitor. Coconut shells have high lignocellulosic content and are not being fully utilized in Indonesia. The lignocellulose could be converted into activated carbon for use as the electrode on a hybrid supercapacitor. This research focused on studying the effect of the addition of carbon nanotube (CNT) composite to porous graphene-like nanosheets (PGNS) as the electrode on a hybrid supercapacitor. The PGNS and CNT composite were synthesized via simultaneous activation and carbonization. Nickel oxide was used as the counter electrode. The CNT composite had a large surface area of 1374.8 m2g-1, pore volume of 1.1 cm3g, and pore size of 3.2 nm. On the other hand, the PGNS had a surface area of 666.1 m2g-1, pore volume of 0.47 cm3g, and pore size of 2.8 nm. The electrode pair between the NiO and the activated carbon achieved 5.69 F/g and 94.1% cycle durability after 10 charging and discharging cycles. The composite had an energy density of 0.38 W h kg-1. The aim of this research was to provide an alternative formula for producing high-performance supercapacitor materials.

DEVELOPMENT OF ELECTRODE DEPOSITION METHODS FOR SCALE-UP OF DYE SENSITIZED SOLAR CELLS Mutiari, Anies; Ananda, Wisnu; Widiatmoko, Pramujo; Devianto, Hary; Nurdin, Isdiriayani; Adriaan, Adriaan; Utomo, Mhd Ridho; Koto, Hilham Zamriko
Journal of Engineering and Technological Sciences Vol 52, No 1 (2020)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar

This research studied the effect of electrode deposition method on the performance of dye-sensitized solar cells (DSSCs). Four deposition methods (bar coating, doctor blade coating, screen printing, and spray coating) were compared. For commercial production purposes, applicability of the methods to a scaled-up DSSC was studied. In order to minimize the production cost, commercial activated carbon was utilized as counter electrode. The experimental results showed that the doctor blade technique provided the best DSSC performance among the investigated methods. Based on the study of cell I-V characteristics, the photoelectric conversion efficiency of the DSSC with an electrode active area of 70 cm2 was significantly lower than with 5 cm2 despite using the same deposition method. The electrochemical characteristics of the cells were further studied using electrochemical impedance analysis.

Synthesis and Characterization of Hydrochar and Bio-oil from Hydrothermal Carbonization of Sargassum sp. using Choline Chloride (ChCl) Catalyst Rustamaji, Heri; Prakoso, Tirto; Rizkiana, Jenny; Devianto, Hary; Widiatmoko, Pramujo; Guan, Guoqing
International Journal of Renewable Energy Development Vol 11, No 2 (2022): May 2022
Publisher : Center of Biomass & Renewable Energy, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/ijred.2022.42595

The purpose of this study is to alter the biomass of Sargassum sp. into elective fills and high valuable biomaterials in a hydrothermal process at 200oC for 90 minutes, using ZnCl2 and CaCl2 activating agents, withChClas a catalyst. This method generatedthree primaryoutputs: hydrochar, bio-oil, and gasproducts. ChCl to water ratio varies from 1:3, 1:1, and 3:1. The hydrochar yield improved when the catalyst ratio was increased, but the bio-oil and gas yield declined. The highest hydrochar yields were 76.95, 63.25, and 44.16 percent in ZnCl2, CaCl2, and no activating agent samples, respectively.The porosity analysis observed mesopore structures with the most pore diameters between 3.9-5.2 nm with a surface area betweenÂ 44.71-55.2. The attribute of interaction between activator and catalyst plays a role in pore formation. The hydrochar products with CaCl2 showed the best thermal stability. From the whole experiment, the optimum hydrochar yield (76.95%), optimum surface area (55.42 m2 g-1), and the increase in carbon content from 21.11 to 37.8% were achieved at the ratio of ChCl to water was three, and the activating agent of ZnCl2. The predominant bio-oil components were hexadecane, hexadecanoic, and 9-octadecenoic acids, with a composition of 51.65, 21.44, and 9.87%, respectively the remaining contained aromatic alkanes and other fatty acids. The findings of this study reported that adding activating agents and catalysts improve hydrochar yield and characteristics of hydrochar and bio-oil products, suggesting the potential of hydrochar as a solid fuel or biomaterial and bio-oil as liquid biofuel

Heavy hydrocarbon recovery with integration of turboexpander and JT valve from highly CO2-containing natural gas for gas transmission pipeline Yusupandi, Fauzi; Widiatmoko, Pramujo; Sukmana, Ira Febrianty; Fitri, Hera Rahma; Eviani, Mitra; Devianto, Hary
Jurnal Rekayasa Proses Vol 17, No 2 (2023)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.82485

Demand of natural gas is predicted to increase since many valuable products can be produced. Water and heavy hydrocarbon content are the key for gas pipeline facility. To meet requirement of natural gas transportation, dehydration unit (DHU) and hydrocarbon dew point control unit (DPCU) are necessary to avoid water and hydrocarbon condensation during transmission. The conventional dehydration technology, TEG contactor, can lower water content from 1,304 mg/m3 to 80.35 mg/m3 where the maximum limit of water content in natural gas is 97 mg/m3 to prevent hydrate formation. DPCU is installed to remove heavy hydrocarbon, especially C5+. Integration of JT valve and turboexpander was employed to obtain the low gas dew point. The hot gas stream that entered the JT valve was observed. The lower hot bypass gas was applied, the lower hydrocarbon dew point and the more condensate flowrate was achieved. indohoki77 adalah salah satu platform judi online terkemuka yang menyediakan berbagai jenis permainan bagi para penggemar judi di Indonesia.The highest power generation can be gained at low hot gas flow ratio which also influenced the exit pressure and temperature of compressor. In pipeline simulation, the pressure and temperature drop occurred at the high hot gas rate. To examine the arrival condition, dew point curves were generated and showed that the limitation of hot gas flow ratio has to be below 0.6 to prevent heavy hydrocarbon condensation in pipeline.

Heavy hydrocarbon recovery with integration of turboexpander and JT valve from highly CO2-containing natural gas for gas transmission pipeline Yusupandi, Fauzi; Widiatmoko, Pramujo; Sukmana, Ira Febrianty; Fitri, Hera Rahma; Eviani, Mitra; Devianto, Hary
Jurnal Rekayasa Proses Vol 17, No 2 (2023)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.82485

Demand of natural gas is predicted to increase since many valuable products can be produced. Water and heavy hydrocarbon content are the key for gas pipeline facility. To meet requirement of natural gas transportation, dehydration unit (DHU) and hydrocarbon dew point control unit (DPCU) are necessary to avoid water and hydrocarbon condensation during transmission. The conventional dehydration technology, TEG contactor, can lower water content from 1,304 mg/m3 to 80.35 mg/m3 where the maximum limit of water content in natural gas is 97 mg/m3 to prevent hydrate formation. DPCU is installed to remove heavy hydrocarbon, especially C5+. Integration of JT valve and turboexpander was employed to obtain the low gas dew point. The hot gas stream that entered the JT valve was observed. The lower hot bypass gas was applied, the lower hydrocarbon dew point and the more condensate flowrate was achieved. indohoki77 adalah salah satu platform judi online terkemuka yang menyediakan berbagai jenis permainan bagi para penggemar judi di Indonesia.The highest power generation can be gained at low hot gas flow ratio which also influenced the exit pressure and temperature of compressor. In pipeline simulation, the pressure and temperature drop occurred at the high hot gas rate. To examine the arrival condition, dew point curves were generated and showed that the limitation of hot gas flow ratio has to be below 0.6 to prevent heavy hydrocarbon condensation in pipeline.

The Study of Hydrothermal Carbonization and Activation Factors' Effect on Mesoporous Activated Carbon Production From Sargassum sp. Using a Multilevel Factorial Design Prakoso, Tirto; Rustamaji, Heri; Yonathan, Daniel; Devianto, Hary; Widiatmoko, Pramujo; Rizkiana, Jenny; Guan, Guoqing
Reaktor Volume 22 No.2 August 2022
Publisher : Department of Chemical Engineering, Faculty of Engineering, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/reaktor.22.2.59-69

Seaweeds are large-scale multicellular marine algae categorized based on color as Chlorophyceae, Rhodophyceae, and Phaeophyceae. No information has been provided on the conditions affecting the production of mesoporous activated carbon from one member of the described aquatic plants, namely Sargassum sp. Therefore, this study aimed to determine the impact of the main factors and their interactions on Sargassum sp.-derived activated carbon manufactured (SAC) by hydrothermal carbonization and CO2 activation methods. A mathematical approach was employed using a multilevel factorial design with the main factors being the activator type (ZnCl2, CaCl2, & KOH), hydrothermal temperature (200, 225, & 250oC), and activator ratios (2 & 4). Meanwhile, the response variables were yield and BET surface area (SBET) of SAC. Morphological, functional, crystallographic, and porosity characterization was carried out on the samples. The SAC-Ca-200-2 sample had the highest yield, with the value being 26.5 percent of weight. The activators having the highest specific surface area (SBET) were SAC-Zn-250-4, SAC-Ca-225-2, and SAC-K-250-2, with 1552, 1368, and 1799 m2/g, respectively. The pore size distribution in SAC products ranged from 2.16 to 10 nm in diameter. The analysis conducted indicated the activator type and interaction with its ratio substantially impacted the SAC yield value; besides, only the activator type affects the formation of high surface area pores.

Synthesis of rubber seed shell-derived porous activated carbons for promising supercapacitor application Rustamaji, Heri; Prakoso, Tirto; Devianto, Hary; Widiatmoko, Pramujo; Febriyanto, Pramahadi; Ginting, Simparmin br; Darmansyah, Darmansyah
International Journal of Renewable Energy Development Vol 14, No 2 (2025): March 2025
Publisher : Center of Biomass & Renewable Energy (CBIORE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61435/ijred.2025.60869

This work investigates synthesizing activated carbon obtained from rubber seed shells utilizing several activating agents (KOH, CaCl2, and ZnCl2) for supercapacitor applications. Activated carbon was produced from a rubber seed shell using hydrothermal carbonization at 275 °C for 60 minutes and a 120-minute activation treatment at 800 °C. Various activating agents pronounced impacted the pore architecture, surface area, crystallinity, and level of graphitization, which collectively determined the electrochemical characteristics of the resulting materials. Incorporating activation agents enhances the specific surface area and influences the extent of graphitization of activated carbon. The specific surface area of activated carbon products ranges from 367 to 735.2 m² g⁻¹. Further investigation through electrochemical analysis, conducted with a carefully engineered two-electrode system, demonstrated a peak electrode capacitance value of 246 F g-1 at 50 mA g-1 for an ACZn-based supercapacitor. Supercapacitor cells’ energy and power densities reached significant levels, measuring 5.47 Wh kg-1 and 246 W kg-1, respectively. The RSS-derived activated carbon-based supercapacitor exhibited remarkable longevity in a 5000-cycle test, with consistent capacitance retention and coulombic efficiency of 100.11% and 100%, respectively. This work presents a sustainable pathway for producing activated carbon electrodes, contributing to the global circular economy and demonstrating considerable industrial potential.

Morphological and thermal stability analysis of Sn/C electrodes synthesized through impregnation and precipitation methods for CO2 electroreduction Eviani, Mitra; Prakoso, Tirto; Kusdiana, Dadan; Widiatmoko, Pramujo; Devianto, Hary
International Journal of Renewable Energy Development Vol 14, No 5 (2025): September 2025
Publisher : Center of Biomass & Renewable Energy (CBIORE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61435/ijred.2025.61280

This study investigates tin (Sn) based electrodes supported by graphite for the electrochemical reduction of carbon dioxide (ECO2R) to formic acid, comparing precipitation and impregnation synthesis methods. Electrodes were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Thermogravimetric Analysis (TGA), Cyclic Voltammetry (CV), Chronoamperometry, and Electrochemical Impedance Spectroscopy (EIS). The precipitation method yielded higher Sn content (91.22%) and superior thermal stability (3% mass loss at 1000°C vs. 45% for impregnation). Morphological analysis through SEM revealed precipitation-synthesized electrodes exhibited more uniform Sn particle distribution across the graphite surface, while impregnation resulted in larger Sn agglomerates with less homogeneous coverage, significantly influencing electroactive surface area and catalytic performance. The electrochemical performance of electrodes was tested using H-cell. CV showed decreased cathodic current for Sn/C electrodes compared to pure graphite in CO2-saturated electrolyte, while chronoamperometry indicated slightly better sustained performance for precipitation-synthesized electrodes with stabilized current densities after 3 hours of operation. EIS analysis suggested the precipitation method yields a marginally lower ohmic resistance (28.8 Ω vs. 29.8 Ω), resulting in a more favorable electrode structure for overall catalytic activity. Both methods showed lower ohmic resistance than that of pure graphite (38.1 Ω), the precipitation-synthesized Sn/C electrode emerged as the preferred selection for ECO2R to formic acid, balancing high Sn content, thermal stability, superior durability, and better Faradaic efficiency. The observed performance differences were attributed to distinct metal-support interactions formed during synthesis, with precipitation creating stronger metal-carbon bonds that enhance stability but potentially limit certain active sites necessary for optimal CO2 reduction kinetics. This comprehensive characterization revealed that the precipitation-synthesized electrode offers the most promising foundation for further development, potentially through process optimization, hybrid synthesis approaches, or targeted doping strategies to enhance catalytic activity while maintaining the advantageous stability characteristics.

Heavy hydrocarbon recovery with integration of turboexpander and JT valve from highly CO2-containing natural gas for gas transmission pipeline Yusupandi, Fauzi; Widiatmoko, Pramujo; Sukmana, Ira Febrianty; Fitri, Hera Rahma; Eviani, Mitra; Devianto, Hary
Jurnal Rekayasa Proses Vol 17 No 2 (2023): Volume 17, Number 2, 2023
Publisher : Jurnal Rekayasa Proses

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.82485

Demand of natural gas is predicted to increase since many valuable products can be produced. Water and heavy hydrocarbon content are the key for gas pipeline facility. To meet requirement of natural gas transportation, dehydration unit (DHU) and hydrocarbon dew point control unit (DPCU) are necessary to avoid water and hydrocarbon condensation during transmission. The conventional dehydration technology, TEG contactor, can lower water content from 1,304 mg/m3 to 80.35 mg/m3 where the maximum limit of water content in natural gas is 97 mg/m3 to prevent hydrate formation. DPCU is installed to remove heavy hydrocarbon, especially C5+. Integration of JT valve and turboexpander was employed to obtain the low gas dew point. The hot gas stream that entered the JT valve was observed. The lower hot bypass gas was applied, the lower hydrocarbon dew point and the more condensate flowrate was achieved. The highest power generation can be gained at low hot gas flow ratio which also influenced the exit pressure and temperature of compressor. In pipeline simulation, the pressure and temperature drop occurred at the high hot gas rate. To examine the arrival condition, dew point curves were generated and showed that the limitation of hot gas flow ratio has to be below 0.6 to prevent heavy hydrocarbon condensation in pipeline.

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