Isolated metal atoms immobilized on substrates, termed single-atom catalysts (SACs), represent a groundbreaking advancement in catalytic science, particularly for addressing environmental challenges. Their exceptional catalytic performance originates from their unique atomic-level structure and high atom utilization efficiency. This review delves into the structure–property relationships of SACs in environmental remediation applications, encompassing their classification, composition, and design strategies. Subsequently, the application of SACs in photocatalysis and electrocatalysis for contaminant elimination, water purification, and gas pollutant conversion was discussed. Moreover, the potential future research directions for SACs in environmental remediation are thoroughly explored. This review aims to offer insights into the structure, performance, and catalytic mechanisms of SACs to develop more efficient and environmentally friendly catalytic materials, providing a novel approach to address environmental pollution.

Plastic waste has become a serious environmental issue and has attracted increasing attention. Various treatment technologies have been developed for the remediation of this waste, including degradation, recycling and upcycling, and transformation to value-added products has been extensively studied. Transitioning plastic waste into carbon-based functional materials is especially attractive because of the practical applications of plastic wastes derived carbon materials (PWCMs) in the field of green energy and in sustainable environmental practices. Herein, recent advances in the preparation and applications of PWCMs are systematically reviewed. Thermal treatment methods for synthesizing carbon-based materials from plastic waste are summarized, including anoxic pyrolysis, catalytic and pressure carbonization techniques, flash Joule heating and microwave conversion. The applications of PWCMs and PWCMs-based composites to green energy storage and production (such as in batteries, supercapacitors and water-splitting systems) and sustainable environmental concepts (pollutant adsorption/degradation, solar evaporation and CO₂ capture) are detailed, with an emphasis on the property-performance correlation. The potential for future development of PWCMs is also examined. This review is meant to provide insights into the advanced applications of PWCMs and to stimulate the future upcycling of plastic waste.