Composite adsorbents for carbon capture: Unifying zeolite and activated carbon properties to overcome limitations in CO₂ separation

The mitigation of anthropogenic carbon dioxide (CO₂) emissions necessitates the development of adsorbents that combine high efficiency, durability, and scalability under realistic post-combustion conditions. Zeolites exhibit strong electrostatic interactions and exceptional selectivity toward CO₂, but their hydrophilicity leads to severe performance losses in humid flue gas. Activated carbons (ACs), in contrast, give hierarchical porosity, hydrophobicity and high performance. stability of regeneration, yet have poor intrinsic CO 2 affinity because their reactions are limited to van der Waals forces. Zeolite–activated carbon (Zeolite–AC) composites have thus become a promising hybrid adsorbent, which combines microporosity of zeolites is crystalline with the mesoporosity and strength of AC.This review critically examines synthesis strategies, such as physical activation, chemical activation and post-synthetic functionalization as the main pathways to customize the pore architecture and interfacial chemistry. The activation pathways of surface area, micropore is stressed mesopore balance, and functional group distribution, and in what ways these two are used to regulate adsorption capacity, selectivity and cyclic stability. Functionalization methods, including nitrogen doping and amine grafting, are discussed as the important ways to improve CO 2 affinity and moisture selectivity. In addition to material summaries, the performance relationships between synthesis structures and performance are associated with adsorption energetics and regeneration behavior, which provides mechanistic framework to design rational compound composites. Through synthesizing scattered innovations, the review establishes avenues into which Zeolite-AC composites could be scaled and sustained to capture industrial CO 2 levels, such as their application to temperature, vacuum, and electro-swing adsorption cycles. • Zeolite–AC composites integrate microporosity, mesoporosity, and stability. • Activation pathways govern surface area, pore balance, and CO₂ uptake. • Amine grafting and N-doping enhance CO₂ affinity and moisture tolerance. • Structure performance links explain adsorption energetics and regeneration. • Scalable routes enable Zeolite–AC deployment in TSA, VSA, and ESA processes.