领域：学术论文 · 自然科学

Plastic products derived from petroleum refining have become indispensable in daily life due to their lightweight nature, low production cost, and excellent durability [1]. According to relevant statistics, global plastic consumption has surged from 335 million tons in 2016 to 400 million tons in 2021, showing a continuous upward trend [2]. During the COVID-19 pandemic, the demand for single-use personal protective equipment (PPE) such as masks and gloves, along with packaging materials, surged dramatically. It is estimated that over 450 billion plastic-based PPE items were used globally in 2020 alone [3]. Moreover, the widespread adoption of fast-paced lifestyles has driven the rapid growth in the food delivery and e-commerce sectors, significantly increasing the consumption of plastic packaging materials. However, despite the convenience plastics bring to modern life, the growing dependence on them has led to increasingly severe challenges in waste management. Owing to the large-scale production and short service life of most plastic products, post-use plastics continue to accumulate in the environment, leading to mounting pollution and increasingly complex waste management issues.
Currently, the scientific community is actively addressing the challenges of plastic recycling and resource recovery by exploring a range of efficient and viable chemical transformation pathways, including hydrogenolysis, alcoholysis, glycolysis, and pyrolysis [4,5,6]. Under ideal conditions, chemical conversion pathways should enable the efficient recovery of high-purity monomers from plastic waste, with the recovered products exhibiting quality and reactivity comparable to those of virgin feedstocks, allowing for direct reutilization in the synthesis of new polymers. This approach not only significantly improves resource utilization efficiency but also paves the way toward genuine “closed-loop recycling” [7,8]. However, plastics—particularly thermosets and highly cross-linked polymers—exhibit exceptional chemical stability due to their dense three-dimensional network structures and robust carbon–carbon backbones, which severely hinder their degradation under mild conditions. As a result, current chemical recycling technologies typically require harsh operating conditions—such as elevated temperatures (>180 °C), high pressures (20–40 atm), and concentrated alkali (1–10 M) or strong acids (e.g., concentrated H2SO4 or HNO3) as reaction media. While these conditions facilitate polymer-chain scission and improve reaction rates, they also pose significant challenges, including high energy consumption, severe equipment corrosion, secondary environmental pollution, and limited economic feasibility [9,10,11]. Therefore, the development of mild and green plastic conversion technologies operable under ambient or near-ambient conditions is a critical breakthrough toward achieving sustainable plastic recycling.
Photo-driven photocatalytic technology is regarded as a highly promising strategy for sustainable plastic waste management. In general, photocatalytic plastic conversion systems can be broadly categorized into the following two types: photodegradation and photosynthetic transformation (Figure 1) [12]. The ability to selectively generate value-added products is one of the key criteria distinguishing photodegradation from selective photo-reforming processes. As shown in Figure 1a, conventional photodegradation typically aims at mineralization, relying on highly oxidative radicals (e.g., •OH) to indiscriminately attack polymer backbones and intermediates. This results in complex reaction pathways and broad product distributions, with final products dominated by CO2, water, and trace organic acids, offering limited value [12,13]. In contrast, photosynthetic conversion emphasizes precise regulation of reaction pathways to efficiently convert hydrocarbon content in plastics into chemically valuable target molecules (e.g., H2, C1–C2+ fuels, and aromatic compounds) (Figure 1b) [14]. Therefore, the transition to photosynthetic systems hinges on the modulation of radical type, concentration, and spatial reactivity to prevent uncontrolled mineralization by overly oxidative species.
In this review, we first provide a brief overview of the current status of plastic waste treatment with respect to the basic reaction mechanisms involved in the photocatalytic process for plastics, with special emphasis on the redox pathways and the roles of key reactants in the photocatalytic process. We then systematically summarize representative recent advances in photocatalytic plastic waste conversion, categorized by plastic type (e.g., polyolefins and polyesters) (Figure 2), and critically analyze the performance and applicability of different catalytic systems. Finally, we discuss the key challenges in achieving efficient and selective transformation of plastic waste, including catalyst stability, compatibility with real-world plastics, product selectivity control, and system-level economic feasibility. We also outline future directions in catalyst design, mechanistic investigation, reaction engineering scale-up, and industrial deployment. We hope this review offers theoretical insights and technical references that contribute to the green transition of plastic pollution management and resource recovery.
The management of plastic waste has attracted widespread global attention due to its significant impact on the sustainability of human life. A variety of techniques are employed in managing plastic waste, including incineration, landfill disposal, microbial degradation, and mechanical shredding with subsequent recycling, as well as transformation methods driven by electricity, heat, or light. These approaches each offer distinct advantages and limitations in the effort to reduce environmental impact and recover value from discarded plastic materials (Figure 3) [15,16,17,18,19,20,21]. Currently, plastic waste is primarily managed through landfilling and incineration, while a substantial fraction is still discharged directly into natural environments [22]. Among various plastic products, packaging materials are particularly problematic, as they are prone to entering rivers, lakes, and oceans, posing significant threats to aquatic ecosystems [23]. With the continuous growth in global plastic production and the diminishing availability of landfill space, the economic burden of plastic waste management has increased markedly. More critically, landfilling not only leads to a considerable waste of petroleum-derived resources but also gives rise to severe environmental concerns, including the leaching of chemical additives and long-term land occupation [24]. Similarly, although plastic incineration allows partial energy recovery, it is far less efficient compared to recycling and entails high environmental costs [25]. The life-cycle carbon footprint of incinerated polymers is substantial, with an estimated 5 to 10 tons of CO2 emitted per ton of plastic processed [17]. Furthermore, incineration can produce toxic byproducts [26], rendering it a suboptimal strategy from both ecological and energy standpoints. Mechanical recycling typically follows a downcycling approach, wherein waste plastics are physically processed through shredding, washing, and remelting [27]. However, the resulting recycled materials are often utilized in the production of low-performance products, such as flower pots or non-food-contact containers [28]. This degradation in material quality leads to a reduction in overall polymer value, liTo address the inherent limitations of conventional recycling approaches, catalytic upcycling has emerged as a highly attractive alternative. This strategy enables the efficient conversion of polymeric waste into high-value chemicals, fuels, and other functional materials with significant economic potential, offering a promising complement to existing recycling methods [29]. Electrocatalysis has demonstrated promising conversion efficiency in the treatment of polymeric waste, offering advantages such as mild operating conditions and product selectivity. However, its reliance on external electrical energy input and the current limitations in electrode material selection, reactor design, and long-term operational stability pose significant technical challenges that must be addressed to enable practical application [30]. Thermocatalytic conversion is highly efficient and offers excellent reaction stability, enabling the rapid cleavage of C–C bonds to produce value-added chemicals. However, the requirement for elevated temperatures and substantial energy input imposes constraints on its scalability and practical implementation [31]. Enzymatic biotechnology relies on highly specific plastic-degrading enzymes, which have a limited substrate scope and face challenges in processing complex or mixed plastic waste. Moreover, these enzymes often exhibit poor stability under harsh reaction conditions. Fermentation, which converts plastic-derived intermediates into valuable chemicals through microbial metabolism, typically requires tedious pretreatment steps to depolymerize plastics into fermentable substrates. This complicates the process workflow and significantly increases downstream separation and purification costs [32]. Photocatalytic conversion has emerged as a promising strategy for plastic waste treatment due to its mild reaction conditions, high energy efficiency, and potential for selective transformation. As shown in Figure 4, operating under ambient temperature and pressure and utilizing solar or ultraviolet light as the energy source, photocatalysis presents a more economically viable and environmentally friendly alternative compared with conventional thermal and chemical degradation methods [33]. Unlike pyrolysis or incineration, which require high energy input and often generate toxic byproducts, photocatalytic processes can proceed under mild conditions with minimal environmental risk. Furthermore, many photocatalytic systems leverage solar energy, enhancing their long-term sustainability and cost-effectiveness. Certain photocatalysts have demonstrated the ability to selectively cleave polymer chains or oxidize specific moieties, enabling the conversion of plastic waste into valuable monomers or fine chemicals. Compared with enzymatic biotechnology, which relies on highly specific enzymes and suffers from limited substrate scope and low stability under harsh conditions, photocatalytic systems exhibit broader applicability. They can effectively process both homochain and heterochain polymers by modulating reactive oxygen species (•OH, •O2−) and optimizing catalyst active sites. Similarly, microbial fermentation—despite its potential for converting plastic-derived intermediates into chemicals—often requires tedious and costly pretreatment to break down polymers into fermentable substrates, complicating process workflows and increasing separation burdens. In contrast, photocatalysis offers an integrated platform for both degradation and upcycling, enabling direct, selective conversion of plastic waste without extensive preprocessing. Its ability to control radical activity also helps suppress over-oxidation, thereby favoring the formation of high-value products. Taken together, the synergistic advantages of photocatalytic technology, including mild operational conditions, solar energy utilization, broad substrate compatibility, and direct value-added conversion, position it as a highly efficient and sustainable core strategy for addressing plastic waste. In comparison, other emerging alternatives remain constrained by energy intensity, substrate specificity, or process complexity.miting its potential for reuse in high-end applications.

翻译考点：
考点1：【single-use personal protective equipment (PPE)】 应译为 【一次性个人防护用品】，其中的“equipment”不可译为“设备”
考点2：【chemical transformation pathways 】应译为 【化学转化路径】
考点3：【glycolysis】 应译为 【乙二醇解】
考点4：【polyolefins and polyesters】 应译为 【聚烯烃与聚酯类】
考点5：【life-cycle carbon footprint】 应译为 【全生命周期碳足迹】
考点6：【reactive oxygen species】 应译为 【活性氧物种】
考点7：【homochain and heterochain polymers】 应译为 【同链/均链与异链/杂链聚合物】
考点8：【green transition of plastic pollution management】 应译为 【塑料污染治理的绿色转型】