•PDIC12/CuTcPc p-n heterostructure is a novel organic composite photocatalyst.•PDIC12 greatly promotes the visible light-driven photocatalytic activity of CuTcPc.•PDIC12/CuTcPc displays excellent visible light photocatalytic activity (λ > 400 nm).•The resulting hydroxyl radical (OH) played the major roles for RhB degradation.•Provide useful insights to improve the performance of traditional photocatalysts.Among photocatalytic materials, p-n heterojunction-type photocatalysts has good photocatalytic performance under visible light irradiation. Herein, a novel Copper phthalocyanine/perylene diimide derivatives p-n heterojunction photoeatalysts based on the intermolecular hydrogen bond between pyridyl and carboxyl was designed and characterized using FT-IR, UV–vis and photoluminescence spectra, and then compared their photocatalytic performance by degradation for rhodamine B (RhB) under visible light irradiation. The hydrogen bond composites shows significant higher photocatalytic activity comparing with its parent, and the photocatalysis increased with increasing of mole fraction of perylene diimide derivatives. The change of morphology and p-n heterojunction structure are in favor of the high photocatalytic active. Furthermore, the photocatalytic mechanism was investigated by radical scavengers testing, that confirmed hydroxyl radical (OH) was the main reactive species for the degradation of RhB.A novel PDIC12/CuTcPc p-n heterojunction-type photoeatalysts for enhancing photocatalytic performance under visible-light irradiation.

Here, we propose a simple, effective method to prepare expanded graphite in which the intercalation and expansion of graphite are realized by only one step under ambient conditions, not involving any heating or any sophisticated devices. We demonstrate that the expanded graphite prepared by such an one-step room-temperature method exhibits an expansion volume of up to 225 times. Most importantly, the used amount of concentrated H2SO4, which acts as the intercalant, can be dramatically decreased by about 85% in comparison to that used in the conventional methods, which will greatly reduces the effluent and alleviate the environmentally detrimental effect caused by the excessive usage of H2SO4.

The nanoscale microporous carbide-derived carbon (nano-CDC) is synthesized by chlorination of silicon carbide nano-powder with a particle diameter around 60 nm and further pore-tuned by KOH activation with different KOH/nano-CDC ratios. Based on the higher specific surface area (SSA), a hierarchical micro- and meso-pore structure (especially for the greatly produced mesopores), and the shorter inherent ion transport distance within porous nano-carbons, the KOH-activated nano-CDC exhibits superior supercapacitive performances. Its specific capacitance is up to 141 F g−1, 156% increase compared with that of pristine nano-CDC (54 F g−1). Most interestingly, the cyclic voltammogram curve of the activated nano-CDC can keep a rectangular-like shape even at a scan rate of 5000 mV s−1, exhibiting significantly better power performance. This work confirms that constructing favorable pore structure in nanometer-sized porous carbons is an effective strategy for fabricating high-power supercapacitors.

•Introduction of core–shell CNT@AC can impede the stacking of graphene sheets.•Introducing CNT@AC among graphene sheets leads to high SSA and abundant micropores.•Graphene and core–shell CNT@AC hybrid exhibit superior supercapacitive performance.Many works have demonstrated that the graphene and carbon nano-tube hybrid (RGO/CNT), synthesized by introducing CNT among graphene sheets, can exhibit improved supercapacitive performance. However, due to its relatively low specific surface area (SSA) and undeveloped pores, the introduced CNT has limited contribution to the electrochemical performance. To solve the problem, we have synthesized a hybrid (RGO/CNT@AC) of graphene and core–shell CNT@AC by introducing activated porous carbon-coated carbon nanotube (CNT@AC) among the graphene sheets. The SSA and micropore volume of RGO/CNT@AC are greatly higher than those of RGO/CNT. Moreover, RGO/CNT@AC shows superior supercapacitive performance compared with RGO/CNT in 6 M KOH electrolyte. The highest specific capacitance is up to 193 F g−1 at a scan rate of 10 mV s−1, much higher than that (91 F g−1) of RGO/CNT. Furthermore, RGO/CNT@AC also shows obviously better rate capability (138 F g−1 retention at a high scan rate of 5000 mV s−1) and excellent cycling stability (almost 100% capacitance maintaining in cycling stability test). The significant improvement in supercapacitive performance of the RGO/CNT@AC hybrid should be ascribed to the abundant micropores contributed by the AC coated on the CNT surface and more diffusion paths existing between RGO sheets.

•Introduction of nano-CDC can effectively impede the stacking of graphene sheets.•Graphene/nano-CDC composites own higher SSA and developed pore structure.•Graphene/nano-CDC composites exhibit excellent supercapacitive performance.Introducing carbon nanotube (CNT) or carbon black (CB) among graphene sheets has been demonstrated an effective strategy to impede the restacking of graphene sheets and eventually enhances the supercapacitive performance. However, due to their relatively low specific surface area (SSA) and undeveloped pores, the introduced CNT or CB itself has limited contribution to the electrochemical performance. To address the problem, we have synthesized a graphene/nanometer-sized carbide-derived carbon (graphene/nano-CDC) composite. Benefiting from the introduction of the porous nano-CDC, the graphene/nano-CDC composite behaves higher SSA and developed pore structure, and thus superior supercapacitive performance. The specific capacitance of the graphene/nano-CDC composite can reach 195 F g−1 at a scan rate of 5 mV s−1, a 179% increase compared with RGO (only 70 F g−1). Most interestingly, even at the scan rate of 5000 mV s−1, its cyclic voltammogram curves can still keep a relatively typical rectangle shape and the capacitance retention can maintain 67% (130 F g−1), approximately 5 times higher than those of the RGO (13%, 9 F g−1). In addition, the specific capacitance of the graphene/nano-CDC composite is quite stable over the entire cycle numbers, and has no significant degradation even after 10,000 cycles.

An isolable and ambient stable bay-substituted perylene diimide adical anion salt was straightforwardly synthesized by base catalysis reduction of N,N-diethylhexyl-1,7-di(pentafluoro-phenoxyl) perylene diimide (DFPDI) in polar solvents, such as acetone, DMF, DMSO, NMP in yields of 48.7 %. Elemental analysis and 1H NMR, 13C NMR and EPR were carried out to confirm the formation of the compounds. Solvent-dependent cyclic voltammetries revealed the only condition for generating DFPDI radical anion in polar solvents—the reduction potential (DFPDI/DFPDI−) is more positive than −0.36 V (vs. Ag/AgCl). Redox studies revealed that DFPDI radical anion was not only ambient stable to moderate oxidants air (O2) and moisture for prolonged existence but also sensitive to strong oxidants-acid H+ and strong oxidization metal ions with low limit value.

Unsymmetrical N-pyridyl-N′-3,4,5-trialkoxy phenyl perylene diimides (PDIs) with yield of 28–32% were obtained using one-step method and the optimized condition. A consistent decrease of absorption coefficients can be observed by UV–vis absorption spectra when the length of the alkoxy chains increased. The new combination of pyridyl and alkoxy phenyl on perylene diimides leads to hydrogen bonds composites with interesting morphological behaviors.The synthesized the unsymmetrical N-pyridyl-N′-3,4,5-alkoxy phenyl perylene diimides (PDIs) with acceptable yield, which easily form hydrogen bonds composite with terephthalic acid by COH…N intermolecular hydrogen bonding.

•The introduction of carbon nanotube can impede the stacking of MXene sheets.•Introducing carbon nanotube can improve the electrical conductivity of MXenes.•The d-Ti3C2/CNT composites exhibit excellent supercapacitive performance.MXenes, a new family of two-dimensional materials, are terminated by O, OH and F groups. The existence of the oxygen-containing functional groups indicates a potential application in supercapacitor based on a redox mechanism. However, the irreversible stacking of MXenes will lead to an insufficient utilization of these functional groups and thus a decrease in the supercapacitive performance. To solve the problem, we synthesized a composite material comprised of carbon nanotube (CNT) and Ti3C2 sheets (d-Ti3C2) delaminated from MXenes by ultrasonic stirring. The FTIR result suggests that the ultrasonication has no significant effect on the oxygen-containing functional groups. The resultant composites exhibit significantly higher volumetric capacitance and better capacitance retention (during 5–100 mv s−1) than d-Ti3C2. A highest volumetric capacitance of 393 F cm−3 at 5 mv s−1 in KOH electrolyte can be obtained when the weight ratio of d-Ti3C2 to CNT is 2:1. In addition, the volumetric capacitance has no significant degradation even after 10000 cycles in cycling stability test, showing an excellent cycling stability compared with metal oxides. These enhanced electrochemical performances can be ascribed to the introduction of CNTs, which impede the stacking of Ti3C2, enlarge the distance between Ti3C2 sheets and improve the electrical conductivity.

•Oxygen-containing functional groups can improve the wettability of graphitized CDC.•The treated CDC exhibits great improvement in specific capacitance and rate capability.•The work proposes a route to improve supercapacitive behavior of graphitized carbons.A graphitized carbide-derived carbon (CDC), synthesized by chlorination of TiC at 1000 °C, has high specific surface area (SSA), hierarchical micro- and meso-pores, and excellent electrical conductivity. However, the low hydrophilicity leads to poor supercapacitive in alkaline electrolyte. A strategy that introducing oxygen-containing functional groups onto the graphitized CDC by nitrate acid treatment is presented to improve its surface wettability. The treated CDC exhibits a great increase in specific capacitance (from 11.3 to 146 F g−1) and, most interestingly, an enhanced power capability, a rectangular shape being maintained in CV curves even at the scan rate of 500 mV s−1. The superiority of the treated CDC is caused by the improved wettability, maintained mesopores and high accessible SSA. Moreover, the introduction of oxygen-containing functional groups contributes the pseudocapacitance of graphitized CDC. Therefore, HNO3 treatment is a promising way to improve the supercapacitive performance of graphitized carbon materials with mesopores and high specific surface area.

•Hierarchical porous carbon can be obtained by catalysis of microporous CDC.•Hierarchical porous carbon exhibits excellent supercapacitive performance.•Catalyzing CDC may be an effective strategy to tune the CDC pore structure.Microporous carbide-derived carbon (CDC) with both high SSA and extremely narrow pore size distribution is synthesized by chlorination of niobium carbide powder. The produced microporous CDC is catalyzed at 1000 °C by using nickel nitrate as the catalyst. This treatment leads to the formation of a small amount of mesopores and slight decrease in the SSA. Electrochemical investigations show that the specific capacitance of the CDC catalyzed by nickel nitrate is almost as high as that of the pristine CDC in 6M KOH electrolyte. Furthermore, its cyclic voltammogram curves can keep a rectangular-like shape even at a scan rate of 500 mV s−1, a significant improvement compared with that of the pristine CDC, indicating that the catalyzed CDC as an electrode material for supercapacitor exhibits superior specific capacitance and rate performance. Therefore, catalyzing CDC may be regarded as a facile and effective strategy to tune the CDC pore structure to match the applications of supercapacitor or some others.

Graphitized carbide-derived-carbon (CDC) with hierarchical micro- and meso-pores is synthesized by chlorination of titanium carbide powder at 1000 °C. The produced CDC has many bilayer graphenes and some narrow graphite ribbons, which contributes a large amount of micropores (∼1.35 nm) and some mesopores. Although hierarchical pore is an attractive structure for supercapacitor, the low hydrophilicity of the graphitized CDC leads to poor electrochemical performance in alkaline electrolyte. The specific capacitance of the CDC in KOH aqueous electrolyte is only 5 F g−1. A strategy that adding ethanol to alkaline electrolyte is presented to improve its surface wettability. The specific capacitance of the graphitized CDC in KOH aqueous electrolyte with addition of ethanol increases to 60 F g−1 at a scan rate of 20 mV s−1. The optimal content of ethanol in KOH electrolyte is 10 wt.%. In addition, cyclic voltammogram curve can maintain a quasi-rectangular shape well even at a scan rate of 500 mV s−1 and the retention rate of the specific capacitance is about 70%. The specific capacitance is stable at high current density (e.g. 1 A g−1), and almost no performance degradation is observed after 8000 consecutive cycles.

•Wettability and contact angle of carbide-derived carbons (CDCs) are investigated.•Hydrophilicity and specific capacitance of CDC depend on its microstructure.•Well-ordered graphite ribbons have lower hydrophilicity and capacitance.•A strategy that improving the surface wettability and capacitive behavior of CDC.Porous carbide-derived carbons (CDCs) are synthesized from TiC at different chlorination temperatures as electrode materials for electrochemical capacitors. It is found that the microstructure of the produced CDCs has significant influence on both the hydrophilicity in aqueous KOH electrolyte and the resultant electrochemical performance. Because the TiC-CDC synthesized at higher temperature (e.g. 1000 °C) contains well-ordered graphite ribbons, it shows lower hydrophilicity and specific capacitance. It is also found that addition of a small amount of ethanol to KOH electrolyte effectively improves the wettability of the CDCs synthesized at higher temperature and the corresponding specific capacitance. Compared with the CDC synthesized at 600 °C, the CDC synthesized at 1000 °C shows fast ion transport and excellent capacitive behavior in KOH electrolyte with addition of ethanol because of the existences of mesopores and high specific surface area.

•Porous carbons prepared from carbides using chlorination method.•Carbon volume fraction in carbide precursor affects the pore structure.•Pore size in CDC depends on the thickness of the produced graphite.•Pore size distribution of NbC–CDC is insensitive to chlorination temperature.Porous carbide-derived carbons (CDCs) are synthesized by chlorination of carbides with different carbon volume fractions in the temperature range from 400 to 1000 °C. It is found that the volume fraction of carbon atoms in carbide precursor has much influence on pore structure of the produced CDC. It is prone to form well ordered graphite to chlorinate carbides with high carbon volume fraction (e.g. VC and TiC). Interlayer spacing of the produced graphite is about 0.34 nm. Its thickness increases with chlorination temperature, which leads to a monotonous increase of pore size in the produced CDC. As for the CDCs synthesized from carbides with low carbon volume fraction (e.g. NbC), it is mainly composed of single or bi-layer graphene. The pore size distribution of these NbC–CDCs is insensitive to chlorination temperature. NbC–CDC synthesized at moderate temperature (600 or 800 °C) contains a large amount of micropores (∼0.8 nm) and small amount of mesopores. Since almost all of these micropores are end-opened, the produced NbC–CDC has high specific surface area (>2000 m2 g−1).Carbide-derived carbon (CDC) is a new type of carbon nano-material produced by selective remove of the non-carbon atoms from carbide lattice layer by layer. Atomic-level control can be achieved in the synthesis process. The pores in CDC can be regarded as the result that the space of the original carbide particle is divided by the produced graphite. For the carbides with the same crystal structure, carbon volume fraction in carbide has big influence on the pore structure of the produced CDC. Tuning the carbon volume fraction in carbide can be an effective way to produce CDC with desirable application.

A microstructure control strategy for carbide-derived carbon (CDC) by ball-milling the metal carbide precursor prior to CDC synthesis is investigated. This work explores the effect of chlorination temperature and ball-milling time on the microstructure, specific surface area (SSA) and the pore size distribution. It is found that the degree of order of CDC obtained from the milled titanium carbide (TiC) is obviously high and can be well tuned by controlling the ball-milling time at a lower chlorination temperature (400–800 °C). As the chlorination temperature rises to 1000 °C, an obvious decrease in the degree of order is observed and many cubic diamond-like carbon nanoparticles with larger d-spacing are formed. In addition, the produced CDC has a high SSA with both micro- and meso-pores. The effect of ball-milling TiC precursor on the microstructure of CDC can be attributed to the iron (Fe) in the TiC from the milling balls and jar to a great extent. The Fe promotes the formation of the better-organised carbon at lower chlorination temperature and the formation of the nano-diamond at higher temperature.

Porous carbide-derived carbons (CDCs) are synthesized from different carbide (VC, TiC, NbC) as electrode materials for electrochemical capacitors. The process of carbide–carbon transformation is investigated by observations at different carbide/CDC interfaces. It is found that the restructuring process has much influence on formation of microstructure as well as the resultant electrochemical performance. The carbon structure in the produced CDC is well in accordance with that formed at the carbide/CDC interface, indicating that the microstructure in the produced CDC is decided by re-bonding of the residual carbon atoms. It is further found that the internal stress during carbide–carbon transformation has much influence on the CDC microstructure. In addition, the microstructure in CDCs is dependent on the volumetric concentration of carbon atoms in carbide precursor. Lower volumetric concentration of carbon atoms facilitates the formation of CDC with short and curved graphene structure, which owns easily accessible pores and large specific surface area, and thus high electrochemical performance for ultracapacitor. A novel strategy that controlling microstructure of CDC through controlling the volumetric concentration of carbon atoms in carbide precursor is presented. This strategy is very effective to form designed microstructure of CDC for electrochemical applications.

•CDC are obtained from the chlorination of VC in the presence or absence of iron.•The degree of order increases monotonously with chlorination temperature for VC-CDC.•A sharp decrease in the degree of order for VC/Fe-CDC is observed at 800 °C.•VC/Fe-CDC observed at 800 °C shows the highest specific surface area.•VC/Fe-CDC observed at 800 °C shows a good electrochemical performance.Carbide-derived carbons (CDCs) are obtained from vanadium carbide powders in the presence or absence of iron catalyst at chlorination temperatures of 400, 600, 800 and 1000 °C. The structural differences of the resulting carbons are characterized by low-temperature nitrogen sorption, Raman spectroscopy, X-ray diffraction, and transmission electron microscope techniques. Unlike monotonous increase in the degree of order for the CDC synthesized without addition of iron catalyst, a various decrease for the CDC synthesized with the catalyst is observed. This difference is due to the formation of many nano-diamonds during the CDC processing in the presence of iron catalyst. Variation in the specific surface area is associated with the degree of order in the CDC. CDC synthesized with iron catalyst at chlorination temperature of 800 °C shows the highest specific surface area, as well as the best electrochemical performance.

Carbide-derived carbon (CDC) was prepared by the chlorination of the 10 h milled SiC powder at 800 °C. The microstructure of the produced carbon was analyzed by High-resolution Transmission Electron Microscope. The results show that there exist a large number of hollow carbon onions in the resultant CDC. Interestingly, all of these hollow carbon onions possess larger lattice spacing. The formation of such carbon onions can be attributed to the existence of the Fe in the SiC grain boundaries. Furthermore, the possible mechanism for the formation of the hollow carbon onions with larger lattice spacing was discussed in this article.Highlights► Chlorination of the ball-milled SiC powder. ► SiC grains are surrounded by Fe in the milled SiC. ► Hollow carbon onions with larger lattice spacing.

The thermal diffusion coefficient, heat capacity, thermal conductivity, and thermal expansion coefficient of Cu76.12Al23.88 alloy before and after cryogenic treatment in the heating temperature range of 25°C to 600°C were measured by thermal constant tester and thermal expansion instrument. The effects of cryogenic treatment on the thermal physical properties of Cu76.12Al23.88 alloy were investigated by comparing the variation of the thermal parameters before and after cryogenic treatment. The results show that the variation trend of the thermal diffusion coefficient, heat capacity, thermal conductivity, and thermal expansion coefficient of Cu76.12Al23.88 alloy after cryogenic treatment was the same as before. The cryogenic treatment can increase the thermal diffusion coefficient, thermal conductivity, and thermal expansion coefficient of Cu76.12Al23.88 alloy and decrease its heat capacity. The maximum difference in the thermal diffusion coefficient between the before and after cryogenic treatment appeared at 400°C. Similarly, thermal conductivity was observed at 200°C.

The microstructure of a Cu-Zn alloy treated under different high pressures was investigated by means of metallographic, scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD), and the hardness of the Cu-Zn alloy was also measured. The results show that the α phase with a smaller grain size, different shapes, and random distribution appears in the Cu-Zn alloy during the solid-state phase transformation generation in the temperature range of 25–750°C and the pressure range of 0–6 GPa. The amount of residual α phase in the microstructure decreases and then increases with increasing pressure. Under a high pressure of 3 GPa, the least volume fraction of residual α phase was obtained, and under a high pressure of 6 GPa, the changes of the microstructure of the Cu-Zn alloy were not obvious. In addition, high pressure can increase the hardness of the Cu-Zn alloy, but it cannot generate any new phase.

A coal tar pitch-derived carbonaceous mesophase (CM) was treated in a high energy ball mill apparatus. The structures for the raw and the as-milled CMs were characterized by X-ray diffraction and Laser-Raman spectroscopic techniques. The structural stability for the as-milled CMs was measured with a differential scanning calorimetry (DSC) measurement system, and the frictional behaviors for the CMs were investigated by using an SRV high temperature friction- and wear- tester. The results have shown that high energy ball milling leads to a drop in the crystallinity of the CMs and a decrease in the size of graphite planar micro-crystals, implying a higher structural amorphism caused by the high energy ball milling. Furthermore, the extended ball milling facilitates the structural amorphous transition for the CMs. In addition, high energy ball milling results in a lower structural stability for the CMs, and the stability further decreases as the ball milling time increases. The CMs display a high temperature lubrication effect. High energy ball milling is supposed to have a beneficial effect to the graphitization of the CMs induced by frictional mechanical action and, therefore, facilitate the high temperature lubrication effect to some extent. This effect can be enhanced through prolonged ball milling.

Metallic elements Ti and Ni were doped into the coal tar pitch-derived carbonaceous mesophase (CM) through mechanical alloying in a high-energy ball milling apparatus. The structures for the raw and Ti/Ni-doped carbonaceous mesophases were characterized by X-ray diffractometer. The friction and wear behavior of the Ti/Ni-doped CMs as lubricating additives at different applied loads and temperatures were investigated using a MMU-5G high temperature friction and wear tester. Worn morphologies of the lower 45# carbon steel specimens were observed by scanning electron microscope (SEM). The carbonaceous substances on the worn surfaces were examined by Raman spectroscopic technique. The results have shown that the Ti/Ni-doped CM through mechanical alloying shows an increase in the crystallinity in comparison to that for the raw CM, implying a transition to the more ordered structures caused by the catalytic graphitization at lower temperatures due to the doped Ti/Ni. The Ti/Ni-doped CMs through mechanical alloying, when used as lubricating additives, displayed an obvious high temperature anti-friction and wear resistant effect, and the lager the applied load, the lower the friction coefficient and the wear severity. In addition, as the applied load increases, the carbonaceous substances on the worn surfaces show a rise in the ordered degree, and the corresponding microcrystalline planar size (La) for the carbonaceous substances becomes larger.

A coal tar pitch-derived carbonaceous mesophase (CM) was treated in a high-energy ball mill apparatus. The structures for the raw and the as-milled CMs were characterized by X-ray diffraction and laser-Raman spectroscopic techniques, and the frictional behaviors for the CMs were investigated by using a SRV high temperature friction and wear tester. The results have shown that, high-energy ball milling leads to a drop in the crystallinity of the CMs and a decrease in the size of graphite planar micro-crystals, implying a higher structural amorphism caused by the high-energy ball milling. In addition, the CMs display a high temperature lubrication effect. High-energy ball milling is supposed to be beneficial to the graphitization of the CMs induced by friction mechanical action, and, therefore, facilitate the high temperature lubrication effect to some extent.

In this paper, we present a novel route to prepare sulfur and nitrogen co-doped reduced graphene oxide, in which, two main procedures – the preparation of a sulfur doped graphite intercalation compound (S-GIC) and the construction of the sulfur and nitrogen co-doped reduced graphene oxide (SN-RGO) – are included. The loading of sulfur and nitrogen in SN-RGO, which is tracked by X-ray photoelectron spectroscopy, is 1.47 and 3.90 at%, respectively. SN-RGO possesses an almost two times higher specific surface area (SSA) than RGO and a narrow pore size distribution. Electrochemical investigations demonstrate that SN-RGO exhibits an outstanding capacitive performance, its specific capacitance at the scan rate of 5 mV s−1 in a 6 M KOH aqueous electrolyte being up to 402.4 F g−1, which is, to the best of our knowledge, among the highest values so far reported for S/N co-doped carbon materials. Furthermore, SN-RGO also exhibits an excellent cycling stability (almost 95% specific capacitance being retained even after 10000 cycles). This work suggests that constructing doped graphene-based materials by using the intercalated substances among the graphite layers as the dopant sources can be considered as a promising strategy for the development of high performance electrodes for supercapacitors.