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Due to the ever-increasing plastic waste causing serious environmental problems, it is highly desirable to recycle it into high-value-added products, such as carbon nanomaterials. However, the traditional catalytic carbonization of hydrocarbon polymers is severely prohibited by the complexity of real-world plastic waste due to the existence of halogen-containing polymers. In this study, through a universal combined template based on magnesium oxide and iron(III) acetylacetonate (Fe(acac)3), a three-dimensional hollow carbon sphere/porous carbon flake hybrid nanostructure is prepared from carbonization of plastic waste with high yields (>70 wt%). This approach is not only suitable for hydrocarbon polymers, but also for halogen-containing polymers. Interestingly, the obtained advanced carbon framework exhibits excellent performance in lithium-ion batteries (802 mA h g−1 after 500 cycles at 0.5 A g−1). The present research paves a new avenue to upcycle plastic waste into a high value-added product. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Porous carbon flakes (PCFs) are prepared from PS waste using MgO as template. • PCFs are used as carbon support for deposition of MnO 2 forming PCF-MnO 2 hybrid. • PCF-MnO 2 exhibits good electrochemical properties as electrode in supercapacitor. • This work provides a practical way to recycle polymeric waste in large-scale. Abstract Due to white pollution related environmental concern and sustainable development requirement, it is desirable to recycle the widely used plastic wastes into products with commercial value, such as high-valued carbon materials which can be applied in electrochemical fields. In this work, porous carbon flakes (PCFs) are produced by direct pyrolysis of polystyrene waste through template method. Furthermore, manganese dioxide (MnO 2) nanosheets are selectively deposited on the surface of resultant PCFs to form hybrid (PCF-MnO 2). Because of the large specific surface area (1087 m2/g) and high conductivity of PCFs, native high specific capacity of MnO 2 , and positive synergistic interaction between PCF and MnO 2 , the resulting hybrid materials show an ultrahigh capacitance of 308 F/g at 1 mV/s and 247 F/g at 1 A/g in LiCl electrolyte, and excellent cycle stability of 93.4% capacitance retention over 10,000 cycles at 10 A/g in symmetric supercapacitor device. This work demonstrates a convenient method for the preparation of cost-effective and high-performance electrode material for electric capacitor. More importantly, it provides a potential way to recycle polystyrene waste into high-valued product in large-scale with disposing of polymeric waste to alleviate environmental concerns. [ABSTRACT FROM AUTHOR]

A facile and efficient method is used to synthesize porous iron oxide coated with graphene as electrode materials for lithium-ion batteries and supercapacitors. Graphene encapsulation of porous Fe2O3 and Fe3O4 nanorods is directly carried out from FeOOH@GO colloids by taking advantage of an electrostatic self-assembly method, owing to the positively-charged surface of FeOOH and the negatively-charged surface of GO. The combination of graphene and porous iron oxide brings about multifunctional features of the electrode materials as follows: (1) enhanced electrical conductivity makes the electrodes the current collectors; (2) reinforced softness of the electrodes accommodates the large volume changes during charge–discharge cycles; (3) improved high specific surface area of the electrodes increases the accessibility of the active electrode materials to electrolyte; (4) the pores formed by graphene and iron oxide particles facilitate ion transportation; (5) iron oxide particles separate graphene and prevent their restacking or agglomeration, and vice versa, thus improving the immersion and splitting of electrolyte into and out of the electroactive material. Consequently, the porous iron oxide/graphene hybrid nanocomposites deliver a good performance in the electrochemical energy storage for lithium-ion batteries and supercapacitors. [ABSTRACT FROM AUTHOR]

Core–shell hybrid particles, possessing a hard core of silica particles (SiPs) and a soft shell of brushlike polystyrene (PS), were successfully prepared by the combination of lithium–iodine exchange (LIE) and surface-initiated living anionic polymerization (SI-LAP). The molecular weight, graft density and brush thicknesses of the PS brushes were controllable. [ABSTRACT FROM AUTHOR]

With the purpose to turn wastes into wealth and develop renewable energy, much effort has been focused on converting biowastes into porous carbons and exploring their application for supercapacitors. In this study, inspired by natural porous structure of biomass and small size of Sn nanoparticles, a one-step strategy was developed to convert waste wolfberry fruits into porous carbons by SnCl 2. The as-fabricated carbon exhibited large specific surface area of 1423 m2 g−1 and hierarchical porosity with total pore volume of 1.36 cm3 g−1. Meanwhile, the newly produced SnCl 2 with more than 95% recovery rate was reused as catalyst. Moreover, the porous carbon was applied for supercapacitive electrode. In three-electrode 6 M KOH system, it displayed outstanding capacitance of 365 F/g at 0.2 A g−1, good rate capability of 75% capacitance retention at 20 A g−1 and excellent cycling stability of 96.4% capacitance retention after 10000 cycles. In two-electrode 1 M Li 2 SO 4 system, its energy density reached 23.2 Wh kg−1 at a power density of 225 W kg−1. The current work provided a facile and low-cost method to recycle renewable biowastes into high-valued carbon material, and further expanded its application for high-performance energy storage devices. [Display omitted] [ABSTRACT FROM AUTHOR]

The integration of solar‐driven interfacial evaporation and electricity co‐generation is considered a promising approach to simultaneously alleviate freshwater scarcity and the energy crisis. However, affected by intermittent solar irradiation/uncontrollable weather, the overall performance of solar‐driven evaporation in the real world is greatly reduced. Herein, inspired by antifreeze proteins in beetles that survive in extreme climates, all‐weather solar‐driven interfacial evaporators with a sandwich structure are designed. The top and bottom layers composed of MnO2‐modified cotton cloth are used for photothermal conversion and water transport, meanwhile, the middle layer made of a phase change microcapsule/hydrogel composite serves for heat storage and release. Under 1 kW m−2 irradiation, the evaporator exhibits a high evaporation rate of 2.67 kg m−2 h−1 and an efficiency of 89.5%. In the dark, the heat released from the phase change layer supports an evaporation rate of 0.43 kg m−2 h−1, 3.6 times that of pure water. Additionally, assembled with a thermoelectric module, the hybrid device achieves a stable output electricity power of 0.42 W m−2 under 1‐sun illumination and a prolonged output for 30 min in the dark. This work provides a novel approach for full‐time solar‐powered steam‐electricity co‐generation and a proof of concept for biomimetic steam generation/heat management integration. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Porous carbon prepared from freeze-dried date sheets. • Porous carbon exhibits an effective pore size distribution in 0.7–0.9 nm. • Porous carbon is used as adsorbents for CO 2 in various temperature and pressure. • This work provides a practical way to develop cost-effective adsorbents. Abstract This work reports a selective chemical activation method for the controllable synthesis of porous carbons with pore sizes ranging from micropores to hierarchical micro/mesopores from date sheets. Through selectively controllable carbonization and combined activation processes, the as-prepared carbon materials exhibit a high specific surface area (3337 m2/g) mainly derived from ultra-micropores in the range of 0.7–0.9 nm, which majorly contributes to CO 2 storage at a low pressure. Among the activated carbon materials prepared, ACDS-800-4 exhibits the highest CO 2 adsorption capacity (that is, 4.36 mmol/g at 25 °C and 1 bar, and 6.4 mmol/g at 0 °C and 1 bar), a good recyclability and selectivity. ACDS-800-6 exhibits a higher CO 2 adsorption capacity of 22 mmol/g at 25 °C and a high pressure of 40 bar. This work demonstrates that the pore size is key to the CO 2 storage at lower pressures while specific surface area plays an important role under high pressure adsorption process. Since these efficient microporous carbons are synthesized from biomass, this work provides a potential way to develop cost-effective adsorbents for removing CO 2 at both low and high pressures and various temperatures. [ABSTRACT FROM AUTHOR]

Upcycling waste plastics into advanced semiconductor photocatalysts provides a new strategy to reasonably and economically solve the huge amount of waste plastics, which remains challenging. Herein, a carbon nitride‐based donor–acceptor (D–A) conjugated copolymer by copolymerization of dicyandiamide and terephthalic acid from discarded polyethylene terephthalate (PET) using Zn(OH)2 as catalyst and template at 360–440 °C is synthesized. The morphology and structure of the conjugated copolymer are well regulated by the calcination temperature. The resultant conjugated copolymer exhibits merits of high light absorption and low electron–hole recombination probability. Consequently, it works excellently in the persulfate‐based advanced oxidation process for visible light‐driven photocatalytic degradation of tetracycline. The kinetic constant (3.4 × 10−2 min−1) is 40.5 and 2.3 times that of the conjugated copolymer system and persulfate system, respectively. Furthermore, the reactive species (including •OH, SO4•−, •O2−, 1O2, and h+) and degradation intermediates of tetracycline are analyzed to expound its degradation process. This work not only pioneers design guidelines on upcycling of waste plastics in a sustainable manner, but also provides a facile strategy to synthesize carbon nitride‐based D–A conjugated copolymers for the efficient activation of persulfate‐based advanced oxidation process in wastewater treatment. [ABSTRACT FROM AUTHOR]

The high vaporization enthalpy of water attributed to the strong hydrogen bonds between water molecules is limiting the performance of solar evaporators. This work demonstrates a deliberate attempt to significantly reduce the vaporization enthalpy of water through the introduction of weak water-amine hydrogen bond interactions in hydrogel evaporators. In this article, bio-based chitosan-agarose/multiwalled carbon nanotube hydrogel film evaporators (CAMFEs) exhibit larger vaporization enthalpy reduction with the presence of primary amine groups in chitosan. An interplay between vaporization enthalpy reduction and water diffusivity leads to an optimal ratio of chitosan to agarose = 7:1 (CAMFE7) showing an impressive evaporation rate of 4.13 kg m−2 h−1 under 1 sun irradiation. CAMFE7 also exhibits excellent salt resistance, with a stable water evaporation rate, using brine water of up to 10 % salinity under continuous 1 sun irradiation. The high mechanical robustness together with its scalability makes CAMFE7 a highly promising material for practical drinking water production. [Display omitted] [ABSTRACT FROM AUTHOR]

Owing to the surge of energy storage devices, lithium and beyond‐lithium metal ion batteries (MIBs) have gained considerable research attention. The large size and multivalent ions drastically deteriorate the performance of conventional battery electrode materials which demands unique types of structures in order to fulfill the electrode requirements of next‐generation MIBs. Developing atomically thin nanosheets confined in 2D heterostructures is a favorable choice to synergistically handle the deficiencies of individual 2D materials and achieve distinct physical and electrochemical properties, retaining their 2D features. This article sheds light on the significance and characteristics of graphene‐based and beyond‐graphene 2D heterostructures as electrode materials in lithium‐ion, sodium‐ion, potassium‐ion, magnesium‐ion, and aluminum‐ion batteries. In this regard, the pathways for the selection of 2D heterostructures electrode materials and their possible geometric configurations are first recognized. Second, the fundamental science, underlying charge storage mechanisms, and robust interfacial charge transfer processes in 2D heterostructures are discussed comprehensively in the context of recent computational studies. Third, the recent state‐of‐the‐art experimental approaches for the fabrication of novel 2D heterostructures and their performance as anode and cathode materials for MIBs are discussed systematically. Finally, the current challenges facing 2D heterostructures and potential future research directions in the context of advanced MIBs are highlighted. [ABSTRACT FROM AUTHOR]

Disposable aluminum cans and plastic bottles are common wastes found in modern societies. This article shows that they can be upcycled into functional materials, such as metal-organic frameworks and hierarchical porous carbon nanomaterials for high-value applications. Through a solvothermal method, used poly(ethylene terephthalate) bottles and aluminum cans are converted into MIL-53(Al). Subsequently, the as-prepared MIL-53(Al) can be further carbonized into a nitrogen-doped (4.52 at%) hierarchical porous carbon framework. With an optical amount of urea present during the carbonization process, the carbon nanomaterial of a high specific surface area of 1324 m2 g−1 with well-defined porosity can be achieved. These features allow the nitrogen-doped hierarchical porous carbon to perform impressively as the working electrode of supercapacitors, delivering a high specific capacitance of 355 F g−1 at 0.5 A g−1 in a three-electrode cell and exhibiting a high energy density of 20.1 Wh kg−1 at a power density of 225 W kg−1, while simultaneously maintaining 88.2% capacitance retention over 10,000 cycles in two-electrode system. This work demonstrates the possibility of upcycling wastes to obtain carbon-based high-performance supercapacitors. [Display omitted] • Upcycle used PET bottles and aluminum cans into the nitrogen-doped hierarchical porous carbons. • Prepared carbon as supercapacitor electrode delivers a high energy density of 20.1 Wh/kg. • Well-defined porous carbon framework is vital to the excellent supercapacitive performance. • This work paves an effective environmental-friendly way to prepare carbon-based supercapacitor. [ABSTRACT FROM AUTHOR]