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Browsing by Author "Pan, Fuping"

Now showing 1 - 2 of 2
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    Block Copolymer-Derived Porous Carbon Fibers Enable High MnO2 Loading and Fast Charging in Aqueous Zinc-Ion Battery
    Guo, Dong; Zhao, Wenqi; Pan, Fuping; Liu, Guoliang (Wiley-V C H Verlag, 2022-04)
    Rechargeable aqueous Zn MnO2 batteries are promising for stationary energy storage because of their high energy density, safety, environmental benignity, and low cost. Conventional gravel MnO2 cathodes have low electrical conductivity, slow ion (de-)insertion, and poor cycle stability, resulting in poor recharging performance and severe capacity fading. To improve the rechargeability of MnO2, strategies have been devised such as depositing micrometer-thick MnO2 on carbon cloth and blending nanostructured MnO2 with additives and binders. The low electrical conductivity of binders and sluggish ion (de)insertion in micrometer-thick MnO2, however, still limit the fastcharging performance. Herein, we have prepared porous carbon fiber (PCF) supported MnO2 cathodes (PCF@MnO2), comprised of nanometer-thick MnO2 uniformly deposited on electrospun block copolymer-derived PCF that have abundant uniform mesopores. The high electrical conductivity of PCF, fast electrochemical reactions in nanometer-thick MnO2, and fast ion transport through porous nonwoven fibers contribute to a high rate capability at high loadings. PCF@MnO2, at a MnO2 loading of 59.1 wt%, achieves a MnO2-based specific capacity of 326 and 184 mAhg(-1) at a current density of 0.1 and 1.0 Ag-1, respectively. Our approach of block copolymer-based PCF as a support for zinc-ion cathode inspires future designs of fastcharging electrodes with other active materials.
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    Cascade degradation and upcycling of polystyrene waste to high-value chemicals
    Xu, Zhen; Pan, Fuping; Sun, Mengqi; Xu, Jianjun; Munyaneza, Nuwayo Eric; Croft, Zacary L.; Cai, Gangshu; Liu, Guoliang (National Academy of Sciences, 2022-08-23)
    Plastic waste represents one of the most urgent environmental challenges facing humankind. Upcycling has been proposed to solve the low profitability and high market sensitivity of known recycling methods. Existing upcycling methods operate under energy-intense conditions and use precious-metal catalysts, but produce low-value oligomers, monomers, and common aromatics. Herein, we report a tandem degradation-upcycling strategy to exploit high-value chemicals from polystyrene (PS) waste with high selectivity. We first degrade PS waste to aromatics using ultraviolet (UV) light and then valorize the intermediate to diphenylmethane. Low-cost AlCl3 catalyzes both the reactions of degradation and upcycling at ambient temperatures under atmospheric pressure. The degraded intermediates can advantageously serve as solvents for processing the solid plastic wastes, forming a self-sustainable circuitry. The low-value-input and high-value-output approach is thus substantially more sustainable and economically viable than conventional thermal processes, which operate at high-temperature, high-pressure conditions and use precious-metal catalysts, but produce low-value oligomers, monomers, and common aromatics. The cascade strategy is resilient to impurities from plastic waste streams and is generalizable to other high-value chemicals (e.g., benzophenone, 1,2-diphenylethane, and 4-phenyl-4-oxo butyric acid). The upcycling to diphenylmethane was tested at 1-kg laboratory scale and attested by industrial-scale techno-economic analysis, demonstrating sustainability and economic viability without government subsidies or tax credits.