Amorphous Carbon Structure Research Articles

Karakteristik Struktur, Fungsionalitas dan Sifat Fisis Silika Aspal Dengan Perbandingan 65%: 35%

Synthesis and characterization of silica composites of rice husk and asphalt with a ratio of 65%: 35% has been carried out. This study aims to see the characteristics of the structure, functionality and physical properties, namely moisture content and thickness development of the sample. The synthesis of silica from rice husks was carried out by the sol-gel method. Based on the research that has been done, the XRD characterization results obtained in the sample have the structure of silica and amorphous carbon, then the results of FTIR characterization show the Si - OH functional group (silanol) occurs at wave number 3528, metal hydroxide Si - OH (silanol) is oxidized to Si - O - Si and Si - O were formed at wave numbers 1081 cm-1, 792 cm-1 and 471 cm-1 and the formation of the C - H stretching functional group occurred at wave numbers 2932 cm-1, 2853 cm-1. Then test the physical properties of water content of 5.813% with a change in thickness development of 9.753%. So it can be concluded that the addition of bitumen to the silica sample changes the phase structure of the sample and changes the original spectrum of rice husk silica.

Embedding Metal–Organic Frameworks for the Design of Flexible Hybrid Supercapacitors by Electrospinning: Synthesis of Highly Graphitized Carbon Nanofibers Containing Metal Oxide Nanoparticles

Electrospun carbonaceous fibers have emerged as promising electrode materials for application in energy storage devices. However, their relatively poor electrical conductivity (due to their amorphous carbon structures) and low capacitive performance lead to poor prospects for their further application. Herein, a universal synthesis of highly graphitized carbon nanofibers, containing various metal oxide nanoparticles (e.g., Fe2O3, NiO), by the pyrolysis of metal–organic framework (MOF)‐embedded electrospun nanofibers, is reported. The resulting carbon nanofibers exhibit large mesopore volumes, contain large quantities of Faradic metal oxide nanoparticles, and are highly graphitized. The fibers also have excellent mechanical flexibility, provide fast ion transfer characteristics, and a large pseudocapacitance combined with excellent electrical conductivity, leading to large specific capacitances. Consequently, asymmetric flexible hybrid supercapacitors assembled from Fe2O3‐embedded highly graphitized carbon nanofibers (FOCNF) and NiO‐embedded highly graphitized carbon nanofibers (NOCNF) exhibit a high energy density of 43.1 Wh kg−1 at a power density of 412.5 W kg−1 and possess excellent flexibility (capacitance retention of 94.4% at 180° bending and 96.2% at 30° twisting) with superior cycling stability. This strategy provides a new MOF‐based approach for the design and synthesis of multifunctional flexible carbonaceous materials and might lead to their further application in flexible energy storage devices.

Effect of Temperature on the Graphitizability and Electrochemical Properties of a Quang Ninh Natural Anthracite Used As Anode in Li/Na-Ion Batteries

In this research, natural anthracite coal (ATC) originated from Vang Danh - Quang Ninh province in Viet Nam was firstly chemically purified and then calcined in inert gas (Ar) at 800 oC for different periods (t = 2, 3 and 6 h) to remove all the impurities and enrich the carbon content. The purity and graphitized structure of treated coal proved significantly while evaluating its structural parameters (the lateral crystallite size - La, stacking crystallite height - Lc, the average number of layers per carbon crystallite - Naverage, and the average number of carbon atoms per aromatic lamellae - n)1, 2 and morphology. After purification step, ATC possesses relatively high carbon content (96.0%) and its impurities were mostly removed. The structure of heat-treated ATC samples is like hard carbon. Besides, its graphene interlayer spacing is larger than that of graphite. These features seem to be potential for application of ATC as negative electrode materials for both Li and Na rechargeable batteries.In batteries testing, using ATC calcined at 800 oC for 3 hours as anode material in lithium half-cell exhibited a quite good specific capacity (170.1 mAh g-1), which is much higher than the value obtained for commercial hard carbon (162.2 mAh g-1). Moreover, Coulombic efficiency of ATC is almost absolute (99.8%). In sodium half-cell, the sample calcined at 800 oC for 2 hours gave much smaller specific capacity of 130.5 mAh g-1 than hard carbon one (280 mAh g-1). Nevertheless, Coulombic efficiency of ATC anode in lithium half-cell and sodium half-cell throughout 100 cycles remained absolutely at 99.6%, while their values for hard carbon anode were 99.9% and 99.7%, respectively. References Abou-Rjeily, J.; Laziz, N. A.; Autret-Lambert, C.; Outzourhit, A.; Sougrati, M.-T.; Ghamouss, F., Towards valorizing natural coals in sodium-ion batteries: impact of coal rank on energy storage. Scientific Reports 2020, 10 (1), 1-10.Manoj, B.; Kunjomana, A., Study of stacking structure of amorphous carbon by X-ray diffraction technique. Int. J. Electrochem. Sci 2012, 7 (4), 3127-34. Acknowledgement This work is supported by Viet Nam National University Ho Chi Minh City (VNUHCM) under grant number B2020-18-06

Mechanism of superlubricity of a DLC/Si3N4 contact in the presence of castor oil and other green lubricants

To meet the surging needs in energy efficiency and eco-friendly lubricants, a novel superlubricious technology using a vegetable oil and ceramic materials is proposed. By coupling different hydrogen-free amorphous carbon coatings with varying fraction of sp2 and sp3 hybridized carbon in presence of a commercially available silicon nitride bulk ceramic, castor oil provides superlubricity although the liquid vegetable oil film in the contact is only a few nanometres thick at most. Besides a partial liquid film possibly separating surfaces in contact, local tribochemical reactions between asperities are essential to maintain superlubricity at low speeds. High local pressure activates chemical degradation of castor oil generating graphitic/graphenic-like species on top of asperities, thus helping both the chemical polishing of surface and its chemical passivation by H and OH species. Particularly, the formation of the formation of −(CH2−CH2)n− noligomers have been evidenced to have a major role in the friction reduction. Computer simulation unveils that formation of chemical degradation products of castor oil on friction surfaces are favoured by the quantity of sp2-hybridized carbon atoms in the amorphous carbon structure. Hence, tuning sp2-carbon content in hydrogen-free amorphous carbon, in particular, on the top layers of the coating, provides an alternative way to control superlubricity achieved with castor oil and other selected green lubricants.

N, P Self-Doped Porous Carbon Material Derived from Lotus Pollen for Highly Efficient Ethanol-Water Mixtures Photocatalytic Hydrogen Production.

Porous biochar materials prepared with biomass as a precursor have received widespread attention. In this work, lotus pollen (LP) was used as the carbon source, a variety of the pollen carbon photocatalyst were prepared by a two-step roasting method. A series of characterizations were carried out on the prepared samples, and it was found that the average particle size was about 40 μm. They also exhibit a typical amorphous carbon structure and a porous structure with a network-like interconnected surface. The photocatalytic hydrogen production performances of lotus pollen carbon (LP-C) and commercial carbon black (CB) were measured under the full spectrum illumination. LP-C-600 showed the best hydrogen production performance (3.5 μmol·g−1·h−1). In addition, the photoelectrochemical (PEC) measurement results confirmed that the LP-C materials show better incident photon-current efficiency (IPCE) performance than the CB materials in the neutral electrolyte. This is because the unique surface wrinkling, hierarchical porous structure, and the N, P self-doping behavior of the LP-C samples are able to improve the light utilization efficiency and the carrier separation/transfer efficiency, thereby further improving the overall hydrogen production efficiency.

Physical and Chemical Properties of Coal Gasification Fine Slag and Its Carbon Products by Hydrophobic-Hydrophilic Separation.

Coal gasification fine slag is a kind of solid waste with low resource utilization rate. The complex embedding of residual carbon and inorganic minerals (ash materials) is the main reason restricting the efficient resource separation and utilization of residual carbon or ash materials. Hydrophobic–hydrophilic separation (HHS) is a separation technology in which mineral particles with different surface hydrophobicity values are enriched in the water phase and oil phase under the action of mechanical stirring. The water on the surface of hydrophobic particles is replaced by the oil phase to form flocs, which are enriched in the hydrophobic liquid phase, while hydrophilic particles are dispersed into the aqueous phase. In this study, the HHS process was used to separate the carbon/ash from the fine gasification slag produced by a Shenning gasifier, Texaco gasifier, and GSP gasifier of Ningxia Coal Industry Co., Ltd. The physicochemical properties of the original sample and the residual carbon products obtained by hydrophobic–hydrophilic separation were analyzed. The results show that HHS can separate the carbon/ash in the three kinds of fine slag to varying degrees. The carbon element is enriched into the hydrophobic phase to form the concentrates, while the silicon element, oxygen element, and metal element enter the tailings. The spherical ash with different particle sizes distributed on the surface of residual carbon and the gap of the matrix is basically removed, while the ash in the carbon–ash melt is difficult to remove. The ash contents of the concentrate and tailings of fine slag of the Shenning gasifier are 22.58 and 96.28%, respectively, which reach the best ash index compared with that of the other two gasifiers. From the change of mineral surface properties after HHS, the distribution of oxygen-containing groups, benzene rings, Si–O, and clay minerals or carbonate minerals in the three kinds of fine slag residual carbon products is basically similar. Compared with the other two gasifier products, the GSP gasifier concentrate has a larger specific surface area and less ash material, more amorphous carbon structures (less graphitic), and more active sites, resulting in a stronger combustion activity.

Relationship between local coordinates and thermal conductivity in amorphous carbon

To determine the correlation between local structure and thermal conductivity of amorphous carbon, we investigated heat conduction in 216-atom systems with different densities (2.0–3.4 g/cm3) using the ab initio molecular dynamics approach. By applying the Allen–Feldman theory with interatomic force constants from ab initio calculations, we report a significant correlation between the thermal conductivity and the density. To clarify which structural characteristics in the high- and low-density cases determine the magnitude of thermal conductivity, we performed geometrical and topological analyses. Coordination number analysis and ring statistics revealed that the sp/sp2/sp3 bond ratios and topological characteristics correlate with density. We also demonstrated that these structural characteristics can be quantified using persistent homology analysis, providing a predictive model of thermal conductivity.

Effect mechanism of carbonaceous materials on the flotation separation of lead–zinc ore

The associated carbonaceous material in ore will deteriorate the flotation process. However, only a few studies have been conducted on the properties of carbonaceous materials in lead–zinc ore flotation. The properties and adsorption performance of carbonaceous materials remain unclear. In this study, the closed-circuit flotation of bench-scale experiments shows that carbon pre-flotation can improve the grade and recovery of lead. The properties of the enriched carbonaceous materials were analysed. Amorphous carbon accounts for 99.70% of the total carbon in the concentrate. The structure of amorphous carbon is similar to the properties of coal, which has rich aromatic rings, carbonyl, and hydrocarbyl. Moreover, amorphous carbon has abundant pore structures with a specific surface area of 16.18 m2/g and an average pore diameter of 12.94 nm. The adsorption isotherm of diethyl dithiocarbamate (DDTC) onto amorphous carbon fits the Freundlich model well. The pseudo-second-order (PSO) model can better interpret the adsorption process. The adsorption capacity of amorphous carbon for DDTC is superior to that of galena, leading to the depletion of DDTC in the flotation pulp.

Atomic coordination dictates vibrational characteristics and thermal conductivity in amorphous carbon

We discuss the role of atomic coordination in dictating the vibrational characteristics and thermal conductivity in amorphous carbon. Our systematic atomistic simulations on amorphous carbon structures at varying mass densities show the significant role played by the ratio of sp2 to sp3 hybridized bonds in dictating the contributions from propagating (phonon-like) and non-propagating vibrational modes and their influence on the overall thermal conductivities of the structures. Specifically, our results show that as the concentration of sp3-bonded carbon atoms increases, the thermal conductivity can be increased by four fold, which is attributed to enhanced contributions from propagating modes in these amorphous structures. Our results shed more light into the role of atomic coordination on dictating heat transfer mechanisms in amorphous materials, and also provide a deeper understanding of the ability to tune the thermal conductivity of amorphous carbon structures through the control of the local atomic coordination.

Modification of Multi-Wall carbon nanotubes using controlled microwave Irradiation: Experimental determination of the enthalpy change

Irradiation of multi-wall carbon nanotubes (MWCNT) was performed at different energy densities to characterize structural changes induced by a highly localized 2.45 GHz electric field. For this purpose, a transversal electric (TE102) resonant microwave cavity was designed and coupled to a standard 800 W microwave oven magnetron. The nanotubes were sealed inside a Pyrex reactor at 10-4 Torr to avoid oxidation or reactions with the environment. Irradiated MWCNT properties were characterized using Raman Spectroscopy, Fourier Transform Infrared Spectroscopy, Thermogravimetry, Solubility tests and Transmission Electron Microscopy. In this work, the energy densities required to modify the MWCNT structure were obtained through an optical method. From an energy density of 82 J/cm3, nanotubes presented nondestructive structural changes, loss of catalytic particles and a decrease of amorphous carbon structures on the surface. A more effective modification with high purity and clearly better structured walls was observed for 167 J/cm3. Furthermore, it was determined that at an energy density of 6.9 KJ/mol a higher purification of MWCNTs is obtained. This value is in agreement with the enthalpy of formation reported for the MWCNTs. This experimental approach could be applied for the functionalization of carbon nanostructures. Finally, the purification process is easily scalable, environmentally friendly and makes maximum use of the irradiated energy.

Effect of pre-carbonization temperature on the porous structure and electrochemical properties of activated carbon fibers derived from kapok for supercapacitor applications

Activated carbon fibers (ACFs) were successfully synthesized from kapok via a two-step process: (i) pre-carbonization and (ii) chemical activation. The pre-carbonization temperature was varied at 300℃, 400℃, and 500℃. The mixing ratio of the pre-carbonized product and potassium hydroxide (KOH) was 3:1, while the activation temperature was 800℃. The effect of pre-carbonization temperature on the morphology, surface area and porosity, chemical functional group, and phase structure of ACFs was investigated and discussed. The characterization results showed that ACFs exhibited an amorphous carbon structure with a hollow fiber shape resembling the kapok. The specific surface area decreased from 487 m2×g-1 to 326 m2×g-1 as the pre-carbonization increased. The pore structure of ACFs possessed a major contribution of micropores, and mesopores became more dominant at a high pre-carbonization temperature. The potential use of ACFs as electrode materials in supercapacitors was electrochemically tested by cyclic voltammetry and galvanostatic charge-discharge measurements. The ACFs obtained from pre-carbonization at 500℃ had the highest specific capacitance of 31.9 F×g-1 at a current density of 1 A×g-1. The results in this work will be a helpful guideline for the further design and development of ACFs from kapok for supercapacitor applications.

High potential of yellow potato (Solanum Tuberosum L.) peel waste as porous carbon source for supercapacitor electrodes

Yellow potato peel contains chemical components such as protein, fiber, starch and sugar which is composed atom carbon chains bonding. Heating potato peel at high temperatures can disrupt the bonding of the carbon atoms of the constituents, vaporizing volatile compounds, thereby producing high carbon fixed. This study preparation yellow potato peel-based carbon electrodes through a single-stage integrated pyrolysis with carbonization from room temperature to 600 °C in N2 gas atmosphere followed by physical activation to a temperature of 850°C in CO2 gas environment. The impregnation of ZnCl2 at different concentrations was optimized as an independent variable precursor to produce porous activated carbon for energy storage devices. The difference in concentration of 0.1M, 0.3M and 0.5M ZnCl2 can increase the porosity, structure of amorphous carbon and the resulting high electrochemical performance. Electrochemical properties were characterized using cyclic voltammetry and galvanostatic charge discharge methods in an aqueous electrolyte of 1M H2SO4 at a voltage of 0-1000 mV and a scanning rate of 1 mV s−1. Furthermore, the resulting specific capacitance increased from 82.82 F g−1, 195.66 F g−1 and 147.03 F g−1 based on the effect of the concentration of the chemical activator ZnCl2. While the specific capacitance obtained using the GCD method shows higher numbers, namely 145.13 F g−1, 223.25 F g−1 and 174.08 F g−1. Energy density 27.18 Wh kg−1 and power density 97.93 W kg−1 from cv method. The simple approach of activated carbon from potato peel waste is expected to produce an economical and simple porous carbon electrode for high performance energy storage application.

Nanoporous Magnetic Carbon Nanofiber Aerogels with Embedded α-Fe/γ-Fe Core–Shell Nanoparticles for Oil Sorption and Recovery

Biomass-based carbon aerogels have received a lot of attention as oil sorbents or oil/water separators due to their effectiveness, low cost, and vast availability of natural resources as their precursors. Magnetically functionalizing the carbon aerogel improves its reusability by magnetic recovery after oil sorption. This work fabricated magnetic carbon nanofibers (MCF) aerogels from the pyrolysis of magnetic bacterial cellulose (MBC) aerogels. The effect of the pyrolysis temperature on the phase transformation and functionalities of the MCF aerogel was investigated. The combined characterization techniques concluded that the MBC aerogel consists of the BC nanofiber matrix decorated with nonmagnetic FeC4H2O4 and magnetic Fe3O4 nanoparticles, which transformed into amorphous carbon nanofibers anchored with the α-Fe/Fe3O4 core–shell structured nanoparticles after pyrolysis at 700 °C. Increasing the pyrolysis temperature to 800–900 °C led to the formation of purer amorphous carbon nanofibers, whereas the nanoparticles turned into the α-Fe/γ-Fe core–shell structure. At 1000 °C, the amorphous carbon structure is better developed and coated on the α-Fe/γ-Fe core–shell nanoparticles. The interpretation explains the results from the magnetic measurement very well and fits perfectly on the Fe–C phase diagram. Furthermore, the MCF aerogels show excellent properties as an efficient oil sorbent, such as large surface area, low density, and hydrophobic properties. Among the samples, the MCF aerogel pyrolyzed at 700 °C (MCF700) exhibits the most desirable properties while requiring the lowest pyrolysis temperature. It could adsorb various oils and organic solvents with high sorption capacity and could be recycled several times. With its magnetic attraction ability, the MCF700 could be magnetically manipulated toward oil, and it could be retrieved after use without direct human contact. These synergistic functionalities make it practically helpful for oil-spill remedies over a large-scale area.

Graphite microcrystals growth in naturally graphitized coal from Hunan, China

The transformation of coal to graphite is a process through which carbon atoms are arranged from amorphous into a crystalline form. However, there is still no study focusing on how the graphite single crystal grow up in graphitized coals during natural graphitization. Herein, a series of naturally graphitized coals were thoroughly studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to uncover the morphological and atomic structural evolution from anthracite to coaly graphite. The anthracite and meta-anthracite samples showed an amorphous carbon structure, whereas the carbon arrangement becomes more and more orderly from semi-graphite to coaly graphite as confirmed by XRD. The crushed particles of anthracite and meta-anthracite show granular and tabular texture with uneven surface under SEM. Small layered graphite flake appears from semi-graphite stage with co-occurrence of dense coal particles, HRTEM data shows the layered graphite flakes are the single graphite crystals. Almost all the dense coal particles change into layered microcrystalline graphite in the most graphitized coals (coaly graphite), and the flaky graphite microcrystals always show up as aggregates. The results will benefit the future applications of the naturally graphitized coals.

Improvement in the physicochemical characteristics of biochar derived from solid digestate of food waste with different moisture contents

The management of digestate from food waste (DFW) has become a worldwide challenge. Pyrolysis is a promising technology to generate biochar from the DFW. However, unlike other biomass, DFW usually has high salt and moisture content, which affects the properties of biochar generated from pyrolysis. The characteristics of biochar derived from DFW with different MCs (5%, 20%, 40%, and 60%) were investigated in the present study. It was found that more micropore and mesopore structures were generated in the biochar with the increase of MC from 5% to 60%, resulting in the Brunauer–Emmett–Teller surface area of the biochar increased from 89.23 m2 g−1 to 117.75 m2 g−1. The MC could also promote the variation of oxygen-containing functional groups and the generation of amorphous carbon structures, which are beneficial for the adsorption property of the biochar. Pyrolysis could stabilize the metals in the biochar, while MC has little effect on the metal speciations. These results provide fundamental information on the impact of MC on the properties of biochar derived from DFW and are important for the optimization of the pre-drying process.

Raman Spectroscopy Characterization of Amorphous Coke Generated in Industrial Processes.

Examples on the real-world field application of Raman spectroscopy with systematic analysis of the intensity variation of D and G bands corresponding to the change of excitation laser energy to characterize and compare coke species from various industrial processes are presented. The findings indicate the different degree of sp2 and sp3 hybridized bonding structures of amorphous carbon collected from different industrial processes as well as heavy carbonaceous deposits generated by industrial catalysts. This spectroscopic methodology is practical and highly beneficial in identifying coke formation mechanisms in industrial processes, as well as supporting design strategies to abate the undesired coke formation on industrial catalysts.

High Surface Area Nanoporous Activated Carbons Materials from Areca catechu Nut with Excellent Iodine and Methylene Blue Adsorption

Nanoporous carbon materials from biomass exhibit a high surface area due to well-defined pore structures. Therefore, they have been extensively used in separation and purification technologies as efficient adsorbents. Here, we report the iodine and methylene blue adsorption properties of the hierarchically porous carbon materials prepared from Areca catechu nut. The preparation method involves the phosphoric acid (H3PO4) activation of the Areca catechu nut powder. The effects of carbonization conditions (mixing ratio with H3PO4, carbonization time, and carbonization temperature) on the textural properties and surface functional groups were studied. The optimum textural properties were obtained at a mixing ratio of 1:1, carbonized for 3 h at 400 °C, and the sample achieved a high specific surface area of 2132.1 m2 g−1 and a large pore volume of 3.426 cm3 g−1, respectively. The prepared materials have amorphous carbon structures and contain oxygenated surface functional groups. Due to the well-defined micro-and mesopore structures with the high surface area and large pore volume, the optimal sample showed excellent iodine and methylene blue adsorption. The iodine number and methylene blue values were ca. 888 mg g−1 and 369 mg g−1, respectively. The batch adsorption studies of methylene dye were affected by pH, adsorbent dose, contact time, and initial concentration. The optimum parameters for the methylene blue adsorption were in alkaline pH, adsorbent dose of 2.8 g L−1, and contact time of 180 min. Equilibrium data could be best represented by the Langmuir isotherm model with a monolayer adsorption capacity of 333.3 mg g−1. Thus, our results demonstrate that the Areca catechu nut has considerable potential as the novel precursor material for the scalable production of high surface area hierarchically porous carbon materials that are essential in removing organic dyes from water.

Investigation of the CN and C2 emission characteristics and microstructural evolution of coal to char using laser-induced breakdown spectroscopy and Raman spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was employed to study the spectral characteristics of the C2 and CN emissions of three types of coal and their pyrolysis char samples. By analysing the atomic and molecular emissions, the electron temperature, electron density and rotational temperature were calculated to evaluate the characteristics of the laser-induced plasma. The correlation between the molecular emissions and coal combustion characteristics was also investigated, which was explained from the aspect of microstructural evolution obtained by Raman spectroscopy. The molecular emissions were gradually inhibited with increasing pyrolysis temperatures, however the molecules tended to distribute at a higher equilibrium temperature. The rotational temperatures increase by 1000–3300 K relative to the raw coal for chars prepared at pyrolysis temperatures of 293–1173 K. The reduction of C2 and CN emissions, which are thought to be mainly caused by small aromatic rings and amorphous carbon structures, is consistent with the Raman spectroscopy results in that the microstructures evolve towards a more stable large aromatic-ring skeleton after pyrolysis. When the carbon conversion ratio is Xc = 50% for three kinds of coal, the R2 values of the exponential fitting between C2 emission and carbon conversion rate are all higher than 0.99.

Effect of sp hybridization and bond-length disorder on magnetism in amorphous carbon- A first-principles study

Magnetism in amorphous carbon system is investigated using first-principle molecular dynamics (MD) and constrained magnetic calculations. The existing literature suggests that sp2-like 3-fold coordinated carbon atoms only play a significant role in obtaining magnetism in amorphous carbon. The present calculations predict the role of the sp1 hybridised atom and the presence of bond-length disorder in sustaining the magnetic moment in the amorphous carbon system. For a low-density amorphous carbon structure with a typical density of 1.0 g/cm3 and below, the sp1-like 2-fold coordinated carbon atoms play an essential role instead of the sp2 atom. In the intermediate density regime, i.e., between 1.0 g/cm3 to 3.0 g/cm3, apart from sp1 or sp2 fraction, the effect of variation in bond length is observed to play a vital role to sustain magnetism in the amorphous carbon system. The origin of magnetism in Q‑carbon in terms of bond-length disorder and change in hybridization ratio is explained.

Karakteristik Struktur Dan Fungsional Aspal Komposit dengan Perbandingan 85%:15%

Synthesis and characterization of rice husk and asphalt silica composites was carried out with a ratio of 85%: 15%. Silica synthesis from rice husk was carried out by the sol-gel method. The materials used in this study were rice husks, asphalt, distilled water, gasoline, NaOH and HNO3. Then the silica and asphalt according to the comparison is set at 110oC. This study aims to look at the structural characteristics, functionality and physical properties, namely water content and thickness development of the sample. Based on the research that has been done, it can be concluded that from the results of XRD characterization the samples have silica and amorphous carbon structures, then based on FTIR characterization shows the -OH (hydroxil) functional groups occur at wave number 3524 cm-1, the hydroxide metal Si-OH (silanol) is oxidized into Si - O - Si and Si - O are formed at wave numbers 1084 cm-1, 810 cm-1 and 462 cm-1 and the formation of the C-H and C=O function group occurs at wave numbers 2923 cm-1 and 2361 cm-1. Then test the physical properties of the water content of 7.642% with a change in thickness development of 4.783%.