In the present study, a coal-based pitch containing 12.1% quinoline insoluble (QI) underwent isothermal heat treatment, and changes in the mesophase microstructure were analyzed for the heat treatment duration. The nuclei creation and growth rate of mesophase were affected by the distribution of QI particles in the pitch. The growth process could be explained in four regions through the mesophase area fraction. During the carbonization of carbon blocks, mesophase formation was induced in the binder phase. The physical properties of carbon blocks were measured as a function of residence time. As residence time increased, bulk density decreased and porosity increased, but electrical conductivity increased. It was determined that forming a mesophase in the binder phase during carbonization reduced the size of large pores in carbon block and improved the connectivity between particles, thereby increasing electrical conductivity. These results are expected to show greater improvement in electrical properties after graphitization.

In this study, the aromatic carbon content of epoxy resin (EP) increased via carbon tar pitch (CTP) modification, and the CTP occurred self-polymerization reaction. The carboxyl and hydroxyl groups of CTP and the hydroxyl and carboxyl groups of EP occurred chemical cross-linking reaction. CTP and graphitization treatment promoted EP CF carbon crystal growth. The graphitization degree of pure EP CF and 40 wt% CTP modified EP CF are 8.42% and 44.21%, respectively. With the increase CTP content, the cell size, ligament junction and density of graphitization modified EP CF gradually increased, while the number of pores and cells gradually decreased. The cell size, ligament junction size and density of 40 wt% CTP modified graphitization EP CF increased to 1200 μm, 280 μm and 0.5033 g/cm3, respectively. EP CF exhibits entangling carbon ribbon and isotropic amorphous carbon. The 40 wt% CTP modified EP CF is composed of evenly distributed amorphous resin carbon and graphite domain CTP carbon. The graphitization modified EP CF improved electrical conductivity, and the electrical conductivity of 40 wt% CTP modified EP CF is 126.6 S/m. The compressive strength can be decided by EP carbon strength and its char yield, and graphitization 40 wt% CTP modified EP CF reached 4.9 MPa. This study provides some basis for preparation and application of CTP modified EP CF.

In this study, Pitch-derived activated carbon (PAC) pellets were by steam activation for automotive carbon canisters. The crystal structure of PAC was analyzed using X-ray diffraction. The textural properties of PAC were studied by Brunauer– Emmett–Teller (BET), Horvath-Kawazoe (HK), and Non-Localized Density Functional Theory (NLDFT) equations with N2/ 77 K isotherm adsorption/ desorption curves. The butane adsorption capacity of the PAC pellets was analyzed according to the ASTM D5228 standard. With increasing steam activation time, the specific surface area and total pore volume of the PAC increased 650–1950 m2/ g and 0.27–1.02 cm3/ g, respectively. The mesopore ratio of PAC increased with increasing activation time and was observed up to 28.4% at 190 min. The butane adsorption capacity of the PAC increased and was observed to range from 10.86 to 51.55%. A close relationship between butane adsorption capacity and pore size (1.47–2.39 nm) was found. Finally, the butane activity of PAC was found to be 51.55% for the steam activated at 950 ℃ for 190 min; this butane activity is 24% better than that of the coconut-derived activated carbon (41.43%) with a similar specific surface area, indicating that pitch is a suitable material for the activated carbon of automotive carbon canisters.

In recent times, there has been a significant demand for supercapacitors in energy storage applications due to their rapid charging– discharging capabilities, high power density, and excellent stability. Nevertheless, the synthesis of electrode materials with a substantial surface area, exceptionally high porosity, and superior electrochemical performance is still challenging. Activated carbons with a distinctive porous structure and exceptional electrochemical properties emerged as promising electrode materials for supercapacitors. In this study, we used a porous activated carbon (PAC) derived from petroleum coke followed by KOH activation as an efficient anodic electrode material. The ultra-high Brunauer–Emmett–Teller surface area of 2105.6 m2 g− 1 with stacked layers of carbon atoms arranged in a two-dimensional hexagonal structure makes the PAC an efficient candidate for a supercapacitor electrode. The PAC delivers a specific capacitance of 470 F g− 1 at a current density of 0.5 A g− 1 over a potential window of 0 to −1 V. The excellent cycling stability in a three-electrode setup with a capacitance retention of ⁓98% even at a high current density of 10 A g− 1 makes the PAC a potential anodic electrode material for high-performance supercapacitor applications.

The pitch-based activated carbon fibers (ACFs) were prepared from ethylene tar-derived pitches containing nickelocene (CNi) or nickel nitrate (NiN). The effects of different anions and contents of metal salts on the microstructure and surface chemical properties of fibers were investigated. The results revealed that Ni2+ from CNi mainly remained its pristine molecule in the organometal salt-derived pitch (OP-xCNi), while Ni2+ from NiN occurred complexation reaction with polycyclic aromatic hydrocarbons (PAHs) in the inorganic metal salt-derived pitch (IP-xNiN) due to the weaker binding ability between anions and Ni2+ of CNi than CNi. The XRD and SEM results confirmed that IP-3NiN-ACF contained Ni, NiO, Ni2O3 nanoparticles with different size distributions, while OP-3CNi-ACF only contained more uniformly distributed Ni nanoparticles with small size. Furthermore, OP-3.0CNi-ACF presented higher specific surface area of 1862 m2/ g and a pore volume of 1.69 cm3/ g than those of IP-3.0NiN-ACF due to the formation of pore structure during the in-situ catalytic activation of different metal nanoparticles. Therefore, this work further pointed out that the desired pore structure and surface chemistry of pitch-based ACFs could be obtained through regulating and controlling the interaction of anion species, metal cations and PAHs during the synthesis of pitch precursors.

Electrochemical reduction of carbon dioxide to valuable chemicals is a promising way of storing renewable energy through electric-to-chemical energy conversion, while its large-scale application is in urgent need of cheap and high-performance catalysts. Herein, we invent a convenient method to synthesize N-doped porous carbon by ammonia etching the pyrolysis carbon of petroleum pitch. We found the ammonia etching treatment not only increase the pyridinic-N content, but also enlarge the specific surface area of the petroleum pitch-based porous carbon. As a cheap and easily available catalyst for carbon dioxide electroreduction, up to 82% of Faradaic efficiency towards carbon monoxide was obtained at − 0.9 V vs the reversible hydrogen electrode in 0.1 M KHCO3. After a long time electrocatalysis of more than 20 h, the Faradaic efficiency of carbon monoxide remains 80%, indicating the porous carbon as made have an ultra-high stability as catalyst for carbon dioxide reduction. Our work provides a new technology to economically prepare efficient electrocatalysts for carbon dioxide reduction.

The pore structure of pitch-based activated carbon prepared by physical activation was improved by nitric acid treatment of pitch. The nitric acid treatment introduced oxygen and nitrogen functional groups on pitch, and increased pitch molecular weight by cross-linking. The introduced oxygen and nitrogen functional groups on pitch were removed during the carbonization process, so they did not directly affect the physical activation process. The increased pitch molecular weight induced an increase of the pitch softening point. The increased softening point prevented rearrangement between the pitch molecules during the carbonization process, thereby inhibiting the orientation improvement of pitch molecules. The crystal degree of the carbonized pitch was reduced due to the inhibition of the orientation improvement. The reduced crystal degree increased reactivity between carbonized pitch and activation agent ( CO2) and formed micropores, so that activated carbon with a high specific surface area could be prepared.

Pyrolysis fuel oil (PFO) is used for the manufacturing of high-purity pitch for carbon precursor due to its high carbon content, high aromaticity, and low heterogeneous element and impurity content. Pitch is commonly classified with its softening point, which is most considerable physical property affecting to various characteristics of the carbon materials based on pitch, such as electrical and thermal conductivity, mechanical strength, and pore property. Hence, the softening point should be controlled to apply pitch to produce various carbon materials for different applications. Previous studies introduce reforming process under high pressure and two step heat treatment for the synthesis of pitch with high softening point from PFO. These methods lead to a high process cost; therefore, it is necessary to develop a process to synthesize the pitch with high softening point by using energy effective process at a low temperature. In this study, waste polyethylene terephthalate (PET) was added to control the softening point of PFO-based pitch. The pitch synthesized by the heat treatment with the addition of PET showed the softening point higher than that of the pitch synthesized with only PFO. The softening point of PFObased pitch synthesized at 420 °C was 138.3 °C, while that of the pitch synthesized by adding PET under the same process conditions was 342.8 °C. It is proposed that the effect of the PET addition on the increase in the softening point was due to the radicals generated from thermal degradation of PET. The radicals from PET react with the PFO molecules to promote the polymerization and finally increase the molecular weight and softening point of the pitch. In addition, activated carbon was prepared by using the pitch synthesized by adding PET, and the results showed that the specific surface area of the activated carbon increased by the addition of PET. It is expected that the pitch synthesis method with PET addition significantly contributes to the manufacture of pitch and activated carbon.

The pitch-based activated carbons were prepared with KOH/KMnO4 as a multiple function activation agent to increase the specific capacitance of a supercapacitor electrode active material. And the porous structure and electrochemical properties of activated carbon were analyzed on varying amounts of KMnO4. KMnO4 was decomposed into K2O, MnO, and O2 at the activation temperature of KOH, and MnO was introduced to activated carbon. K2O/ O2 reacts with a surrounding pitch to generate micropores and forms a pathway that exposes MnO to the outside. It also affects to the specific surface area of activated carbon like KOH chemical activation. The enhanced specific surface area and introduced MnO in activated carbon led to a 28.9% increase in specific capacitance.

Fly ash consists of various metal oxides which can remove SO2 gas by the catalyst effect. When fly ash is added in the preparation process of pitch-based activated carbon, the pitch particles aggregate and fly ash is embedded in the activated carbon. To increase SO2 gas removal performance, activated carbon was prepared by surface-treated fly ash and petroleum-based pitch. Carboxyl groups were introduced into the fly ash by malic acid treatment. The introduced carboxyl groups acted as an activation agent to create micropore around the fly ash, and created micropores were exposed to the fly ash outside of the activated carbon. The exposed fly ash increased removal amount of SO2 gas by a catalytic effect of the metal oxides. The SO2 gas removal performance improved by 34% because of the catalyst effect of the exposed fly ash and improvement in the micropore structure in the activated carbon.

In the present study, carbon molded bodies were prepared by using graphite/coke fillers and petroleum-based binder pitch with various softening points, and the thermal properties of the prepared carbon molded bodies were investigated. The ratio of a binder affects the molded body preparation: no molded body was prepared at a low binder pitch content, and swelling occurred during the thermal treatment at a high binder pitch content. The binder pitch thermal treatment yield was the highest at 41 wt% at the softening point of 150 °C and the lowest at 23 wt% at the softening point of 78 °C. A significant mass reduction was found in the range of 150 to 300 °C in the petroleum-based binder pitch, and in the range of 300 to 475 °C in the coal-based binder pitch. The molecular weight of the binder pitch was analyzed through the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) method. The molecular weight ratio within the interval showing the highest binder pitch molecular weight (178 to 712 m/z) was the highest at 66.4% in the coal-based binder pitch (softening point 115 °C) and the lowest at 46.0% in the petroleum-based binder pitch (softening point 116 °C). When the petroleumbased binder pitch was applied, as the softening point was increased, the voids decreased and thus the thermal conductivity increased. The highest thermal conductivity was 99.5 W/mK for the carbon molded bodies prepared using the coal-based binder pitch and 102.8 W/mK for those prepared by using the petroleum-based binder pitch. The results showed that the thermal properties were similar between the coal-based binder pitch (softening point 115 °C) and the petroleum-based binder pitch (softening point 150 °C).

Spinnable mesophase pitch precursor containing more than 98% mesophase content was successfully prepared from FCC-DO (fluid catalytic cracking-decant oil) without hydrogenation or catalytic reaction. The preparation method involved thermal condensation, vacuum treatment, and annealing treatment. Petroleum mesophase pitch-based carbon fibers are produced by melt spinning of pitch precursors, followed by stabilization and carbonization. The resulting carbon fiber exhibited good mechanical performances up to tensile strength of 2.1 GPa and tensile modulus of 212 GPa, with strain-to-failure higher than 1.0%. These properties ensuring that the automotive grade carbon fibers can be successfully prepared from FCC-DO derived petroleum mesophase pitches through the cost-competitive processes.

In this study, pitch crosslinked by oxygen function groups was made into activated carbon (AC) and pore structure was observed. The oxygen functional groups were introduced by the addition of waste PET for pitch synthesis. Activation agent ratios used to obtain the AC during the activation process were 1:1, 1:2 and 1:4 (pitch:KOH, w/w). The oxygen content in the prepared pitch was characterized by elemental analysis. Also, the molecular weight of pitch was investigated by MALDITOF. Specific surface area and micropore volume of the prepared AC were determined by the argon adsorption–desorption analysis and calculated using the Brunauer–Emmett–Teller and Horvath–Kawazoe equations, respectively. Micropore fraction of PET-free AC was smaller than that of PET-added AC. At high activation agent ratio, mesopores were created when the micropore structure collapsed. However, in the PET-added AC, due to the oxygen crosslinking effect, the micropore structure and micropore size were maintained even at a high activation agent ratio. Therefore, PET AC was found to have a higher micropore fraction than that of PET-free AC.

Pitch precursors affording excellent spinnability, high-level oxidation-resistance, and good carbonization yields were prepared by bromination–dehydrobromination of various ratios of pyrolyzed fuel oil and coal tar pitch. The pitches exhibited spinnabilities that were much better than those of pitches prepared via simple distillation. A pitch prepared using a 1:2 ratio of fuel oil and coal tar pitch exhibited the best tensile strength. Pitch fibers of diameter 8.9 ± 0.1 μm were stabilized at 270 °C without soaking time after heating at a rate of 0.5 °C/min and carbonized at 1100 °C for 1 h after heating at 5 °C/min. The resulting carbon fibers exhibited a tensile strength, elongation, Young’s modulus, and average diameter of 1700 ± 170 MPa, 1.6 ± 0.1%, 106 ± 37 GPa, and 7.1 ± 0.2 μm, respectively.

In this study, we tried to prepare an isotropic spinnable pitch which can be useful to prepare the general purpose carbon fiber through the co-carbonization of biomass tar with ethylene bottom oil under two different preparation methods (atmospheric distillation, pressurized distillation). The results showed that the ethylene bottom oil added co-carbonization was very effective to decrease of the oxygen contents for obtaining a stable spinnable pitch. The pressurized distillation was more effective to reduce the oxygen functional groups of pitches than atmospheric distillation. The obtained spinnable pitch by the pressurized distillation showed higher pitch yield of 42% and lower oxygen content of 9.12% than the spinnable pitch by the atmospheric distillation. The carbon fiber derived from the pressurized distillation spinnable pitch by carbonization at 800ºC for 5 min showed that the higher tensile strength of carbon fiber was increased up to 800 MPa.

Polyacrylonitrile/pitch nanofibers were prepared by electrospinning as a precursor for a gas sensor material. Pitch nanofibers were properly fabricated by incorporating polyacrylonitrile as an electrospinning supplement component. Polyacrylonitrile/pitch nanofibers were activated with steam at various temperatures followed by subsequent carbonization to make carbon nanofibers with a highly conductive graphitic structure. Steam activation was effective in facilitating gas adsorption onto the carbon nanofibers due to the increased surface area. The carbon nanofibers activated at 800°C had a larger surface area and a lower micro pore fraction resulting in a higher variation in electrical resistance for improved CO gas sensing properties.

We demonstrated an effective way of preparing melt spinnable mesophase pitches via catalytic hydrogenation of petroleum residue (fluidized catalytic cracking-decant oil) and their subsequent thermal soaking. The mesophase pitches thus obtained were analyzed in terms of their viscosity, elemental composition, solubility, molecular weight, softening point and optical texture. We found that zeolite-induced catalytic hydrogenation under high hydrogen pressure contributed to a large variation in the properties of the pitches. As the hydrogen pressure increased, the C/H ratio decreased, and the solubility in n-hexane increased. The mesophase pitch with entirely anisotropic domains of flow texture exhibited good meltspinnability. The mesophase carbon fibers obtained from the catalytically hydrogenated petroleum residue showed moderate mechanical properties.

본 연구에서는 열분해잔사유(Pyrolysis Fuel Oil, PFO)를 이용한 Pitch계 활성탄소섬유를 제조하였다. 제조한 Pitch안정화 섬유의 탄화 및 활성화 온도를 850, 880, 900 ℃로 달리하여 각각 다른 샘플의 기공형성에 대한 영향을 알아보기 위해 BET 와 SEM을 이용하여 비교 분석하였다. 세 가지 샘플 ACF850, ACF880, ACF900를 분석한 결과 ACF880의 비표면적과 미세 기공표면적이 각각 1,420 m2·g-1, 1,270 m2·g-1으로 가장 높았으며, 외부비표면적과 BJH흡착누적공극표면에서 가장 낮은 중기공표면적이 도출되었다. 또한 N2가스 등온흡착곡선을 분석한 결과, 미세기공의 분포가 균일한 것을 확인할 수 있었다. ACF880은 흡착률 및 흡착속도에서도 가장 높은 결과값을 보이며, 흡착속도는 미세기공표면적과 비례하며 중기공표면적과 반비례함을 알 수 있었다. 제조한 Pitch계 활성탄소섬유를 라돈 연속측정방법을 통해 48시간 동안 측정한 결과 샘플 모두 라돈 흡착성능을 보였다. 제 조한 샘플 중 ACF880이 34.0%로 가장 높은 흡착률을 보였으며, ACF850이 29.5%로 가장 낮은 흡착률을 나타내었다. 이는 비표면적이 높을수록 흡착률이 높아지는 것을 알 수 있었다. 이를 선형회귀선 기울기로 환산하여 흡착속도로 확인한 결과 ACF880이 -1.89로 가장 빠른 것을 확인하였으며, ACF900이 -1.48로 가장 낮은 흡착속도를 보여 미세기공표면적이 높을수 록, 중기공표면적이 낮을수록 흡착속도가 증가하는 것을 알 수 있었다.