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The development of a new catalyst for the low-cost, environmentally friendly and highly efficient oxygen reduction reaction (ORR) is important for the commercialization of fuel cells. Herein, a smart strategy was proposed for the preparation of a novel nitrogen-doped nanoporous carbon (N-PC) using resource-rich pomelo peel, a type of waste, as starting material. The typical product (N-PC-1000) possesses a high BET surface area (up to 1444.9 m2 g−1), porous structure and high graphitic N content. In alkaline and acidic media, the N-PC-1000 shows not only decent catalytic activities in terms of onset potential and current density, but also has excellent tolerance to methanol poisoning effects and durability. This study provides worthy inspiration for using other environmental wastes to prepare related functional carbon materials with a variety of promising practical applications such as supercapacitors and lithium-ion batteries.

•The porous GO/CTS-HA composite film is successfully synthesized via a facile method.•It is prepared by combining LBL technology with biomimetic mineralization method.•The film with biocompatibility provides platform for the proliferation of mMSCs.•Aspirin can alleviate the pain and give a better environment for bone regeneration.A novel porous graphene oxide (GO)/chitosan (CTS)-hydroxyapatite (HA) nanocomposite film was successfully prepared for the first time by combining layer-by-layer (LBL) assembly technology with biomimetic mineralization method. The LBL technology was used to control the thickness of film as well as induce the biomimetic mineralization of biocompatible HA. The obtained (GO/CTS-HA)n film provided ideal platform for the proliferation of mouse mesenchymal stem cells (mMSCs). The pore size in the film is about 300 nm, and the porous architecture made the film have high aspirin loading efficiency. Also the accumulated loading dosage could be adjusted by the film thickness, and the sustained release of aspirin could ensure well anti-inflammatory effect. The above advantages may alleviate the pain of patients and give the better environment for bone regeneration. This multifunctional aspirin-loaded (GO/CTS-HA)n film provided an inspiration for the synthesis of novel porous inorganic/biomacromolecule nanocomposite films as the biocoatings applied in bone tissue engineering.

•The Fe3O4/Cu2O/Ag composite was first successfully synthesized via a facile method.•The ternary composite shows unexpected photocatalytic activity.•The (111) facet of Cu2O was found be higher activity facet.•The photocatalyst can be easily recycled by a magnet.In this work, a novel magnetic and ordered Fe3O4/Cu2O/Ag ternary composite was successfully synthesized via one-pot method in the presence of Fe3O4 nanoparticles. The glycol-ethanol mixed system was used as both solvent and reductant for the simultaneous formation of Cu2O and Ag. The porous and hollow flower-like Fe3O4/Cu2O/Ag composite was self-assembled by many nanosheets with an average thickness of 10 nm and exhibited unexpected photocatalytic activity for the degradation of methyl orange (MO) under visible light. The degradation rate of MO in aqueous solution (1×10−4 mol L−1) reached to 97.7% within 40 min. The (111) facet of Cu2O exhibited higher activity for the absorption of MO. Furthermore, ternary composite could be easily recycled by applying an external magnetic field without significant decrease of the catalytic activity even after running 5 times, which presented higher stability and efficiency than Fe3O4@Cu2O. This work would provide a new sight for the construction of visible light-responsive photocatalysts with high performance.Photocatalytic Mechanism Scheme of the Fe3O4/Cu2O/Ag composite under visible light irradiation. Such a remarkable photocatalytic activity of composite is related to the surface plasmon resonance effect of Ag nanoparticles and the powerful absorption ability of the (111) facets of Cu2O to MO.

•The black bread reaction experiment process is very facile and fast (about 10 seconds) for producing porous carbon materials.•The method is very practical for mass production, which will speed up as metal-free electrocatalysts commercialization.•The resulting N-PCPs-800 shows decent catalytic activity for oxygen reduction reaction.We successfully synthesized the nitrogen-doped porous carbon particles (N-PCPs) by using a combined “black bread reaction” with thermal annealing in the presence of NH3 atmosphere. The method is very simple and practical for mass production, which will speed up as metal-free electrocatalyst commercialization. The resulting N-PCPs-800 shows decent catalytic activity, longer durability and better tolerance to methanol in alkaline and acidic media due to the high proportion of pyridinic nitrogen atoms and large BET surface area (up to 657.8 m2 g−1). This study can provide facile but efficient and versatile approaches to cost-effective and large-scale production of N-PCPs as metal-free oxygen reduction reaction electrocatalysts for fuel cells (FCs).

A one step method has been developed for the fabrication of hierarchical flower-like bismuth tungstate (Bi2WO6) hollow spheres via a solvothermal process. The size of these microspheres is about 1.5 μm, and the shells are composed of nanosheets with a thickness of about 15 nm. The product has a specific surface area of 95 m2 g−1. The formation mechanism of flower-like Bi2WO6 is proposed, which involves the nucleation and formation of nanoparticles followed by their self-assembly to microspheres, oriented growth, Ostwald ripening and transformation into flower-like hollow microspheres. The Bi2WO6 hollow spheres exhibit excellent visible light catalytic efficiency for the degradation of rhodamine B (RhB), up to 98% within 50 min. The efficiency remains at 92% after five photodegradation cycles due to the hierarchical hollow structure and large surface area.

Developing an effective electrocatalyst for the oxygen reduction reaction is a momentous issue in fuel cells. In this paper, we successfully synthesized the N-doped TiO2 nanorods/graphene (N-TiO2/NG) nanocomposite, which comprise the N-doped TiO2 (N-TiO2) nanorods (40–60 nm diameter and 90–300 nm length) and self-assembled nitrogen-doped graphene (NG) networks. We found that the nanocomposite exhibits great oxygen reduction reaction (ORR) electrocatalytic performance and also shows long durability and methanol tolerance than that of the commercial 20% Pt/C catalyst. This new nanocomposite may also have potential applications in other fields, which are related to energy storage, gas sensors, photocatalysis, and so on.Keywords: N-doped TiO2; nanocomposite; nitrogen-doped graphene; oxygen reduction reaction

•A novel porous tubular Co3O4 was prepared by a simple, eco-friendly and turning waste into treasure method using waste napkin paper as template and organizer.•The formation and self-assembly of Co3O4 nanoparticles occur simultaneously.•The unique Co3O4 tubular structure with many pores could accelerate electrolyte diffusion and Li-ion transport, as well as accommodate the volume change during the charge and discharge progress.•Significant electrochemical performance of porous tubular Co3O4 has been observed.Herein, the novel porous tubular Co3O4 was successfully prepared by a simple, low-cost and eco-friendly process using waste napkin paper as template and organizer. It is very noteworthy that the formation and self-assembly of Co3O4 nanoparticles occur simultaneously. The as-synthesized porous tubular structure with average outer diameter of 2.2 μm is orderly self-assembled by numerous Co3O4 nanoparticles with diameter of 50–150 nm. The specific surface area of typical product is 24.6 m2 g−1 by the BET method, and the majority diameter of pores is about 67 nm. In addition, the effects of different Co2+ concentration on the morphology and electrochemical performance of the products were explored. As anode materials for lithium ion batteries (LIBs), the typical sample shows a high reversible specific capacity (1053 mAh g−1 after 100 cycles at a current density of 100 mA g−1), remarkable cycling performance and a good rate capability of 727 mAh g−1 after 100 cycles at a high specific current density of 500 mA g−1. The excellent electrochemical performance is attributed to the unique porous tubular structure. With these outstanding performances, the as-prepared Co3O4 may be an outstanding candidate anode material for LIBs.(a) Formation mechanism of the Co3O4 product; (b) Cycle performance of Co3O4 samples and coulombic efficiency of Sample 1 at the current density of 100 mA g−1 and (c) Cycle performance and coulombic efficiency of sample 1 at the current density of 500 mA g−1.In this manuscript, the novel 1D porous tubular structure was self-assembled by Co3O4 nanoparticles through a low-cost, eco-friendly and turning waste into treasure method using waste napkin paper as template and organizer. As anode materials for lithium ion batteries (LIBs), the typical sample shows a high reversible specific capacity (1053 mAh g−1 after 100 cycles at a current density of 100 mA g−1), remarkable cycling performance and a good rate capability of 727 mAh g−1 after 100 cycles at a high specific current density of 500 mA g−1. Additionally, this work demonstrates an eco-friendly example for turning waste biomass into treasure and addresses the disposal issue of discard rubbish simultaneously. Furthermore, the as-prepared Co3O4 may be an outstanding candidate anode material for LIBs and our study provides a new way to prepare other porous functional materials.