Segmentation by type of molecular sieve delineates the material families that underpin PSA technology. The most prevalent class is zeolite‑based sieves, subdivided into 13X (high‑capacity for nitrogen and oxygen), 5A (optimal for light hydrocarbons and water), and 4A (effective for moisture control). Activated carbon sieves, characterized by high surface area and microporosity, are employed chiefly for organic vapor adsorption and CO₂ capture. Silica‑gel sorbents, with uniform pore distribution, serve niche roles in moisture‑sensitive PSA cycles. Emerging metal‑organic frameworks (MOFs), such as HKUST‑1 and ZIF‑8, offer tunable pore chemistry and are gaining traction for selective hydrogen and carbon dioxide separations. The relative market contribution of each type aligns with application demands: zeolites dominate (~70 %) due to their proven performance, activated carbon accounts for ~15 %, silica‑gel ~10 %, and MOFs, still in early adoption, represent the remaining ~5 %. This taxonomy clarifies how material choice drives cost, efficiency, and scalability within the Molecular Sieve for PSA market.