The formation of heterojunctions is an e 97542fficient strategy to extend the light response range of TiO 2based catalysts to visible light region. In addition to the bandgap edge match between the narrow bandgap semiconductors and the TiO 2 substrate, a stable phase interface between the sensitiser and TiO 2 is crucial for the construction of heterojunctions, since it acts as a tunnel for the efficient transfer of photogenerated charges. Herein, the coincidence site density (1/Σ) of graphite-like carbon nitride (g-C 3 N 4) nanoflakes and two types of TiO 2 nanofibres [anatase and TiO 2 (B)] was calculated by near coincidence site lattice (NCSL) theory. It was found that the coincidence site density of g-C 3 N 4 and TiO 2 (B) nanofibre with exposed (001) plane is 3 times of that of the g-C 3 N 4 and anatase nanofibre with exposed (100) plane. This indicated that the g-C 3 N 4 nanoflakes are more favourite to form stable heterojunctions with TiO 2 (B) nanofibres. As expected, stable phase interface was formed between the plane of (22-40) of g-C 3 N 4 and the plane (110) of TiO 2 (B) which had same d-spacing of 0.35 nm and same orientation. Under visible light irradiation, the g-C 3 N 4 /TiO 2 (B) system exhibited better photodegradation ability for sulforhodamine B (SRB) dye than g-C 3 N 4 /anatase system, although the photoactivity of the anatase nanofibres was much better than that of the TiO 2 (B) nanofibres. Apparently, the phase interface between g-C 3 N 4 and TiO 2 (B) was more favourable for the electron transfer, which means that the g-C 3 N 4 flakes were easier to sensitise the TiO 2 (B) nanofibres rather than the traditional anatase phase. 65 bandgap semiconductors and thus to extend their visible light response. For instance, core/shell structured g-C 3 N 4 /BiPO 4 photocatalyst displayed superior photodegradation activity for MB dye under UV or visible light irradiation than pure C 3 N 4 or BiPO 4 catalyst, since match of lattice and bandgap edge potential 70 between the C 3 N 4 and BiPO 4 results in the formation of heterojunctions. In addition, g-C 3 N 4 was mixed with TiO 2 to fabricate hybrid photocatalysts via hydrothermal or thermal treatment. These hybrid photocatalysts have displayed high 65 65

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8487wileyonlinelibrary.com high-performance energy storage due to its limited control over specific surface area and insufficient porous channels. [5] And also, the current carbon-based energy storage materials suffer from poor kinetic problems associated with the inner-pore ion transports. [4] Tuning/ optimizing the pore shape, the pore sizes distribution, and the pore connectivity in carbon nanomaterials are very important for improving the electrochemical performance. [6] The hierarchically porous carbon (HPC) materials with optimized micro-, meso-, and macropores are considered to be ideal electrode materials for efficient energy storage. [7,8] Particularly, the mesopores in HPC materials can provide the low-resistant pathways for the ions through the porous particles. The ion-buffering reservoirs can be formed in the macropores that can minimize the ions diffusion distances between the interior surfaces. [9,10] Currently, the regular method to fabricate HPC is the use of hard templates. [11] However, the traditional strategies for fabricating hierarchical architectures hamper their commercial utilization due to the complicated preparation procedure and the involvement of expensive nonrenewable templates. It is still a great challenge for developing a template-free, ecofriendly, and scalable approach to fabricate HPC materials from readily available carbon sources, especially from renewable biomass.The increasing demand for efficient energy storage and conversion devices has aroused great interest in designing advanced materials with high specific surface areas, multiple holes, and good conductivity. Here, we report a new method for fabricating a hierarchical porous carbonaceous aerogel (HPCA) from renewable seaweed aerogel. The HPCA possesses high specific surface area of 2200 m 2 g −1 and multilevel micro/meso/macropore structures. These important features make HPCA exhibit a reversible lithium storage capacity of 827.1 mAh g −1 at the current density of 0.1 A g −1 , which is the highest capacity for all the previously reported nonheteroatom-doped carbon nanomaterials. It also shows high specific capacitance and excellent rate performance for electric double layer capacitors (260.6 F g −1 at 1 A g −1 and 190.0 F g −1 at 50 A g −1 ), and long cycle life with 91.7% capacitance retention after 10 000 cycles at 10 A g −1 . The HPCA also can be used as support to assemble Co 3 O 4 nanowires (Co 3 O 4 @HPCA) for constructing a high performance pseudocapacitor with the maximum specific capacitance of 1167.6 F g −1 at the current density of 1 A g −1 . The present work highlights the first example in using prolifera-green-tide as a sustainable source for developing advanced carbon porous aerogels to achieve multiple energy storage.Adv. Funct. Mater. 2016, 26, 8487-8495 www.afm-journal.de www.MaterialsViews.com Scheme 1. Scheme diagram for the fabrication of the hierarchically porous carbon. EP fibers were decolorized and freeze-dried to get the aerogel of EP. Precarbonized at 700 °C and then activated at 700, 800, a...

Carbon nanomaterials with both doped heteroatom and porous structure represent a new class of carbon nanostructures for boosting electrochemical application, particularly sustainable electrochemical energy conversion and storage applications. We herein demonstrate a unique large-scale sustainable biomass conversion strategy for the synthesis of earth-abundant multifunctional carbon nanomaterials with well-defined doped heteroatom level and multimodal pores through pyrolyzing electrospinning renewable natural alginate. The key part for our chemical synthesis is that we found that the egg-box structure in cobalt alginate nanofiber can offer new opportunity to create large mesopores (∼10–40 nm) on the surface of nitrogen-doped carbon nanofibers. The as-prepared hierarchical carbon nanofibers with three-dimensional pathway for electron and ion transport are conceptually new as high-performance multifunctional electrochemical materials for boosting the performance of oxygen reduction reaction (ORR), lithium ion batteries (LIBs), and supercapacitors (SCs). In particular, they show amazingly the same ORR activity as commercial Pt/C catalyst and much better long-term stability and methanol tolerance for ORR than Pt/C via a four-electron pathway in alkaline electrolyte. They also exhibit a large reversible capacity of 625 mAh g–1 at 1 A g–1, good rate capability, and excellent cycling performance for LIBs, making them among the best in all the reported carbon nanomaterials. They also represent highly efficient carbon nanomaterials for SCs with excellent capacitive behavior of 197 F g–1 at 1 A g–1 and superior stability. The present work highlights the importance of biomass-derived multifunctional mesoporous carbon nanomaterials in enhancing electrochemical catalysis and energy storage.

Thread-like electronic devices have attracted great interest because of their potential applications in wearable electronics. To produce high-performance, thread-like supercapacitors, a mixture of stable dispersions of single-walled carbon nanotubes and conducting polyaniline nanowires are prepared. Then, the mixture is spun into flexible yarns with a polyvinyl alcohol outer sheath by a one-step spinning process. The composite yarns show excellent mechanical properties and high electrical conductivities after sufficient washing to remove surfactants. After applying a further coating layer of gel electrolyte, two flexible yarns are twisted together to form a thread-like supercapacitor. The supercapacitor based on these two yarns (SWCNTs and PAniNWs) possesses a much higher specific capacitance than that based only on pure SWCNTs yarns, making it an ideal energy-storage device for wearable electronics.