Recent advances in waste-derived three-dimensional carbon nanostructures: Synthesis pathways and applications

Carbon nanoparticles derived from carbonaceous waste materials have recently attracted significant attention due to their sustainability, cost-effectiveness, and varied physicochemical properties. Among these, three-dimensional carbon nanostructures, such as carbon aerogels, carbon foams, nanosponges, and graphene-based frameworks, have emerged as promising materials owing to their interconnected porous structures, elevated surface area, remarkable electrical conductivity, and superior chemical stability. These structural attributes usually enhance the efficient charge transport, rapid ion diffusion, and superior mass transfer, making them very suitable for advanced technological applications. This article summarized current breakthroughs in the production and applications of 3D carbon nanomaterials derived from biomass waste. In this context, various manufacturing procedures, including hydrothermal treatment, freeze-drying, templating, activation, and carbonization, were analyzed regarding their structural evolution, and the relationship between structural characteristics and performance was highlighted. This review additionally explored the potential applications of these materials in energy storage devices, environmental remediation, catalysis, sensing, and electromagnetic interference shielding. The discourse addressed current challenges and potential research directions for the large-scale and sustainable synthesis of waste-derived 3D carbon nanomaterials.