ABSTRACT
The random disposal and immature recycling of post-consumer polyethylene terephthalate (PET) packages lead to a severe threaten to the ecological system owing to slow natural degradation kinetics of PET plastic, and meanwhile cause a waste of carbon resources stored in PET plastics. Many methods have been developed to recycle PET plastics, such as mechanical recycling, which induces a reduced quality relative to the virgin PET. In recent years, the photocatalytic conversion of PET plastic wastes into chemicals has received considerable attention due to their unique advantages, including mild conditions, less energy consumption, and simple operation. In this review, we have summarized the latest achievements in photoreforming of PET plastics into value-added chemicals. Primarily, we described the mechanism for bond cleavage during PET photoreforming, the emerging pretreatment methodologies for PET plastics, and the advantages of photocatalytic PET plastics conversion. Then, we introduced electro-/bio-assisted photocatalysis technologies for PET disposal and commented their strengths and limitations. Finally, we put forward the challenges and potential advances in the domain of photocatalytic PET plastics conversion.
ABSTRACT
Electrochemical valorization of polyethylene terephthalate (PET) waste streams into commodity chemicals offers a potentially sustainable route for creating a circular plastic economy. However, PET wastes upcycling into valuable C2 product remains a huge challenge by the lack of an electrocatalyst that can steer the oxidation economically and selectively. Here, it is reported a catalyst comprising Pt nanoparticles hybridized with γ-NiOOH nanosheets supported on Ni foam (Pt/γ-NiOOH/NF) that favors electrochemical transformation of real-word PET hydrolysate into glycolate with high Faradaic efficiency (> 90%) and selectivity (> 90%) across wide reactant (ethylene glycol, EG) concentration ranges under a marginal applied voltage of 0.55 V, which can be paired with cathodic hydrogen production. Computational studies combined with experimental characterizations elucidate that the Pt/γ-NiOOH interface with substantial charge accumulation gives rise to an optimized adsorption energy of EG and a decreased energy barrier of potential determining step. A techno-economic analysis demonstrates that, with the nearly same amount of resource investment, the electroreforming strategy towards glycolate production can raise revenue by up to 2.2 times relative to conventional chemical process. This work may thus serve as a framework for PET wastes valorization process with net-zero carbon footprint and high economic viability.
ABSTRACT
Spinel Co3O4 has emerged as a promising electrocatalyst towards alkaline water oxidation, but its activity is restricted by the undesirable electronic configuration of the octahedral Co3+ site. Herein, we simultaneously manipulate Cr doping and p-n junction engineering on Co3O4 nanorods, which contributes to the formation of Co2+ and Ni3+ octahedral sites with optimal eg fillings, thus achieving a superior OER performance.
