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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. 

Changes in the local atomic arrangement in a crystal caused by lattice-mismatch-induced strain can efficiently regulate the performance of electrocatalysts for zinc–air batteries (ZABs) in many manners, mainly due to modulated electronic structure configurations that affect the adsorption energies for oxygen-intermediates formed during oxygen reduction and evolution reactions (ORR and OER). However, the application of strain engineering in electrocatalysis has been limited by the strain relaxation caused by structural instability such as dissolution and destruction, leading to insufficient durability towards the ORR/OER. Herein, we propose a doping strategy to modulate the phase transition and formation of self-supported cobalt fluoride–sulfide (CoFS) nanoporous films using a low amount of copper (Cu) as a dopant. This well-defined Cu–CoFS heterostructure overcomes the obstacle of structural instability. Our study of the proposed Cu–CoFS also helps establish the structure–property relationship of strained electrocatalysts by unraveling the role of local strain in regulating the electronic structure of the catalyst. As a proof-of-concept, the Cu–CoFS electrocatalyst with doping-modulated strain exhibited superior onset potentials of 0.91 V and 1.49 V for the ORR and OER, respectively, surpassing commercial Pt/C@RuO 2 and benchmarking non-platinum group metal (non-PGM) catalysts. ZABs with the Cu–CoFS catalyst delivered excellent charge/discharge cycling performance with an extremely low voltage gap of 0.5 V at a current density of 10 mA cm −2 and successively 0.93 V at a high current density of 100 mA cm −2 and afforded an outstanding peak power density of 255 mW cm −2 .