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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 AlCl 3 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. 

Electrochemical reduction of CO 2 into value-added fuels and chemicals driven by renewable energy presents a potentially sustainable route to mitigate CO 2 emissions and alleviate the dependence on fossil fuels. While tailoring the electronic structure of active components to modulate their intrinsic reactivity could tune the CO 2 reduction reaction (CO 2 RR), their use is limited by the linear scaling relation of intermediates. Due to the high susceptibility of the CO 2 RR to the local CO 2 concentration/pH and mass transportation of CO 2 /intermediates/products near the gas–solid–liquid three-phase interface, engineering catalysts’ morphological and interfacial properties holds great promise to regulate the CO 2 RR, which are irrelevant with linear scaling relation and possess high resistance to harsh reaction conditions. Herein, we provide a comprehensive overview of recent advances in tuning CO 2 reduction electrocatalysis via morphology and interface engineering. The fundamentals of the CO 2 RR and design principles for electrode materials are presented firstly. Then, approaches to build an efficient three-phase interface, tune the surface wettability, and design a favorable morphology are summarized; the relationship between the properties of engineered catalysts and their CO 2 RR performance is highlighted to reveal the activity-determining parameters and underlying catalytic mechanisms. Finally, challenges and opportunities are proposed to suggest the future design of advanced CO 2 RR electrode materials. 

Rechargeable aqueous Zn−MnO₂batteries are promising for stationary energy storage because of their high energy density, safety, environmental benignity, and low cost. Conventional gravel MnO₂cathodes 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 MnO₂on carbon cloth and blending nanostructured MnO₂with additives and binders. The low electrical conductivity of binders and sluggish ion (de‐)insertion in micrometer‐thick MnO₂, however, still limit the fast‐charging performance. Herein, we have prepared porous carbon fiber (PCF) supported MnO₂cathodes (PCF@MnO₂), comprised of nanometer‐thick MnO₂uniformly deposited on electrospun block copolymer‐derived PCF that have abundant uniform mesopores. The high electrical conductivity of PCF, fast electrochemical reactions in nanometer‐thick MnO_2,and fast ion transport through porous nonwoven fibers contribute to a high rate capability at high loadings. PCF@MnO₂, at a MnO₂loading of 59.1 wt %, achieves a MnO₂‐based specific capacity of 326 and 184 mAh g⁻¹at a current density of 0.1 and 1.0 A g⁻¹, respectively. Our approach of block copolymer‐based PCF as a support for zinc‐ion cathode inspires future designs of fast‐charging electrodes with other active materials.