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Vertically aligned nitrogen doped graphene standing on SiC microspheres (NG on SiC) is prepared by precursor pyrolysis method via a lab-made continuously preparation system. As one of the raw materials, acetonitrile is confirmed have three important effects that could effectively facilitate the nitrogen doping process, significantly promote the lateral dimension and improve graphitization degree of NG on SiC. The metal-free carbocatalyst, NG on SiC, is an efficient selective oxidation catalyst towards targeted C-H bond activation of ethyl benzene. The unique nanostructure of NG on SiC is inborn predispersed graphene which is expected to avoid harmful agglomeration during their preparation, storage, transportation and applications.

Using ultraviolet (UV)-curable 3-(2-(methacryloyloxy)ethyl)-1-alkyl imidazoliums with different alkyl substituents as the bactericidal monomers and trimethylolpropane triacrylate as the crosslinker, highly efficient antibacterial coatings were designed and facilely prepared by a one-step UV-curing method. The differential photocalorimetry experiment showed these monomers polymerized within 120 s under UV irradiation, indicating a very good curable property. The excellent antibacterial activity of these coatings, which reached up to 99.8% ratio against Escherichia Coli, was demonstrated by a shake flask test method.

Boron carbonitride (BCN) nanofibers with rapid and efficient adsorption performance were prepared by electrospinning technology. TEM, XRD, XPS and N2 adsorption–desorption isotherms were performed to study the microstructure of the nanofibers. The results showed that the BCN fibers synthesized at 1000 °C (BCN-1000) have good crystallinity and high specific surface areas (403 m2 g−1). BCN-1000 nanofibers adsorb 70% of amino black 10B (AB-10B) within 10 minutes and reach adsorption equilibrium within 60 minutes. Compared with previous reports, it is found that the adsorption rate of BCN-1000 nanofibers to amino black (AB-10B) is much higher than that of other adsorbents. And BCN nanofibers exhibit a large adsorption capacity (625 mg g−1). In addition, the process of AB-10B adsorption on BCN nanofibers was systematically investigated, which was in accordance with the pseudo-second-order kinetics model and Langmuir isotherm model.

Recently, flexible intelligent wearable devices are in highly demand and it is urgent to increase the flexibility of traditional devices. Organometallic trihalide perovskite materials have become a hot spot in the photoelectric field due to its outstanding optoelectronic properties, which can be crystallized from solutions and vapors. Herein, we demonstrated a simple approach to flexible thin CH3NH3PbI3 perovskite films on paper substrates using a dual-source physical vapor deposition method and a brush-coating method. The photodetector devices from the two methods have similar photodetecting and repeatable performances. They well maintained the optoelectronic functionality under bending conditions. Typically, up to 75% of its initial photocurrent was remained after 500 bending cycles, demonstrating good stability against bending deformation. Additionally, a 6 × 6 perovskite photodetector array based on stretchable origami-based techniques were fabricated. It has excellent all-optical acquisition capability and provides potential application in three-dimensional photo sensing.

Two types of silicon carbide fibers (SiCf) were prepared employing different pyrolysis techniques. The relationship between the microstructure and the electrical resistivity of the fibers was investigated. The results indicated that the carbon layer present on the fiber surface acted as the main conductive phase in the SiCf obtained by direct pyrolysis, whereas a free carbon phase determined the conductivity of the SiCf prepared by the preheated pyrolysis method. A core-shell model and a general effective media (GEM) theory were proposed to explain the conductivity of different types of SiCf. Quantitative analysis based on these models indicated an electrical resistivity of ~10−2 Ω·cm for the carbon layer on the surface of SiCf obtained by direct pyrolysis. The electrical resistivity and the percolation threshold of the free carbon in SiCf prepared by the preheated pyrolysis method were 10−1 Ω·cm and 11.3% respectively.

Recently, flexible and wearable devices are increasingly in demand and graphene has been widely used due to its exceptional chemical, mechanical and electrical properties. Building complex buckling patterns of graphene is an essential strategy to increase its flexible and stretchable properties. Herein, a facile dimensionally controlled four-dimensional (4D) shrinking method was proposed to generate hierarchical reduced graphene oxide (rGO) buckling patterns on curved substrates mimicking different parts of the uniforms. The reduced graphene oxide ridges (rGORs) generated on the spherical substrate seem isotropic, while those generated on the cylindrical substrate are obviously more hierarchical or oriented, especially when the cylindrical substrate are shrinking via two steps. The oriented rGORs are superhydrophobic and strain sensitive but obviously anisotropic along the axial and circumferential directions. The sensitivity of rGORs along the axial direction is much higher than those along the circumferential direction. In addition, the intrinsic solvent barrier property of graphene enables the crack-free rGORs an excellent chemical protective performance, withstanding DCM immersion for more than 2.5 h. The flexible rGORs-based strain sensors can be used to detect both large and subtle human motions and activities by achieving high sensitivity (maximum gauge factor up to 48), high unidirectional stretchability (300-530%), and ultrahigh areal stretchability (up to 2690%). Excellent durability was also demonstrated for human motion monitoring with resistance to hand rubbing, ultrasonic cleaning, machine washing, and chemical immersion.

Two types of silicon carbide fibers with sinusoidal electrical resistivity were prepared by using different pyrolysis technology. The relationship between the microstructure and the electrical resistivity of these fibers was investigated and compared. The results indicated that carbon layer was the main conductive phase in the SiC fibers obtained by means of one step pyrolysis, whereas a free carbon phase governed the conductivity of the SiC fibers prepared through two step pyrolysis mode.

It has been generally accepted that the band gap width of crystallized silicon carbide (SiC) is about two to three times more than silicon. This feature of SiC results in higher activation energy demand during the electron transition, which is vital for maintaining the semiconducting electron transfer. Although this feature used to be considered as a drawback of SiC electronic devices under mild circumstances, now the SiC-based electronics are expected to serve in harsh environments of higher temperature, higher power, and higher frequency conditions. The theoretical design seems practical since SiC nanopapers were discovered. This chapter starts with the review of the preparation of one-dimensional SiC nanostructures (1D SiC) since the 1D SiC are the most ideal building blocks of SiC nanopaper. Especially to the centimeters-long SiC nanowires, the as-prepared SiC nanopapers could be a strong “bridge” between microworld and macroworld due to their unique fabric morphology. Based on practical and potential strategies of organizing 1D SiC into SiC nanopaper, the novel nanopaper has been proved could be practically applied. SiC nanopapers exhibit electrical resistance that linearly increases with increasing environmental relative humidity in a very short time, and high photoelectrocatalytic activity under UV irradiation, which are potentially applied to high performance sensors and new energy transfer devices.

Multi-layer graphene standing on polycrystalline SiC microspheres was prepared by pyrolyzing liquid polysilacarbosilane. The lateral dimension of the multi-layer graphene is ∼100 nm and the average diameter of the microspheres is ∼0.9 μm. The growth of the multi-layer graphene is proposed to be initiated by phase separation of the microspheres, and facilitated with both crystallization inside and chemical vapor deposition outside. This method offers an alternative way to prepare multi-layer graphene on SiC without the need for 4H– or 6H–SiC crystals.

Ribbon-like g-C3N4 was obtained from dicyandiamide using NaCl crystals as the template. Modification of the texture led to an increase of the band gap to 3.0 eV, with much stronger photoluminescence. Hydrogen bonding produces an exceptionally stable dispersion in water. Upon adding different alcohols, various special assemblies were observed to precipitate from the dispersion.

The emission of BCNO phosphors has been easily tuned from the violet to the near red regions by varying the carbon content. Here we report the optimal conversion of graphene oxide (GO) into BCNO hybrid nanostructures by one-step air oxidation with boric acid and urea. White lighting phosphor was obtained in which the doped porous graphene acts as an interconnecting framework generating and transferring electrons under excitation light. Various carbon-related levels in the BN band structures play an essential role in emitting full colour white light. The quantum confinement in the various kinds of GQDs and GO are also beneficial to widen the emission spectrum.

Multi-walled carbon nanotube (MWNT)-reinforced silicon carbide (SiC) ceramic fibers were successfully prepared by blending MWNTs (0–0.5 wt.%) with polycarbosilane, followed by melt spinning, curing, and pyrolysis. The MWNTs used in this study were modified with a chemical treatment. It was found that the MWNTs were well-dispersed in the matrix and aligned with the axis of the fibers after ultrasonic dispersion combined with melt spinning. Mechanical measurements revealed that significant improvement in Young’s modulus and tensile strength was achieved by incorporating MWNTs into the ceramic fibers. The addition of 0.5 wt.% MWNTs led to a 93.6% increase in the Young’s modulus and a 38.5% increase in the tensile strength.

Multi-walled carbon nanotube (MWNT)-reinforced carbon fiber/silicon carbide (Cf/SiC) composites were prepared using a polymer infiltration and pyrolysis (PIP) process. The MWNTs used in this study were modified using a chemical treatment. The MWNTs were found to be well dispersed in the matrix after ultrasonic dispersion, and the mechanical properties of the Cf/SiC composite were significantly improved by the addition of MWNTs. The addition of 1.5 wt.% of MWNTs to the Cf/SiC composite led to a 29.7% increase in the flexural strength, and a 27.9% increase in the fracture toughness.

Axial graded carbon fibers and silicon carbide fibers with sinusoidal electrical resistivity are prepared by continuous pyrolysis of polymer fibers using an elliptic rotating spool. The electrical resistivity of the graded carbon and silicon carbide fibers hereby prepared varies for 1~2 orders of magnitude along the axial direction. The tensile strength of both fiber-types is in normal range without remarkable weak point. Desired period and range of the electrical resistivity can be facilely controlled by adjusting the shape of the rotating spool and the pyrolysis temperature.

Continuous SiC fibers with different thickness of carbon layer were prepared through three preceramic polymer pyrolysis routes. To make the carbon layer thickness controllable, a simple improvement by using a ceramic bushing was adopted to retard the deposition of the pyrolytic carbons. Auger electron spectroscopy (AES) analysis reveals that the carbon layer thickness varies from less than 5 nm to 40 nm. The specific resistivity of the fibers increases by 5 orders of magnitude as the carbon layer thickness decreases. All of the fibers exhibit a tensile strength of around 1.8 GPa which is independent of the carbon layer thickness. The formation process of the carbon layer is discussed in three steps: the decomposition, the carbonization and the deposition. The as-received fibers have a potential application as the reinforcement of functional materials.

Axial graded silicon carbide fibers with fluctuating carbon layer and sinusoidal electrical resistivity in the range of 10 0 –10 2 Ω· cm were prepared. The preparation of these axial graded fibers was simply realized by continuous pyrolysis using an elliptic rotating spool that makes the pyrolysis time of every axial part of the fiber in furnace varies periodically. The period of the electrical resistivity can be facilely controlled by changing the size of the spool. The axial graded fibers have average tension strength of 2.2 GPa without remarkable weak point. The axial graded SiC fiber with sinusoidal electrical resistivity and moderate tension strength is promising in functional applications such as wide frequency range electromagnetic wave absorbing materials, high temperature sensors, shielding materials for harsh environment and so on.

Centimeters-long SiC nanowire could be a strong “bridge” between microworld and macroworld due to its unique morphology, excellent chemical stability, and intriguing physical properties. Here we present a novel “paperlike” material—free-standing SiC nanopaper fabricated by acetone-assisted compression of centimeters-long SiC nanowires. The resistance of this new paperlike material linearly increases with increasing environmental relative humidity in a very short time. We suggest that adsorption of water molecules on SiC nanopaper surface led to fast electron transfer between SiC nanopaper and water layer, which indicates that SiC nanopaper could be applied to high-performance humidity sensor in harsh environment.