Oxidative Dehydrogenation of Light Alkanes Using CO2 as a Mild Oxidant: The Role of the Zeolite Supports

Abstract

Olefins are recognized as important commodity chemicals, with demand continuing to rise due to their central role as building blocks for a wide range of petrochemical products. Low-carbon production routes, together with the increasing availability of light alkanes in natural gas, particularly from shale gas, have intensified the search for alternatives to the energy-intensive steam cracking of petroleum fractions. Beyond the direct dehydrogenation of light alkanes, especially ethane and propane, oxidative pathways using mild oxidants, such as CO2, have emerged as promising options. However, the development of efficient CO2-assisted oxidative dehydrogenation (CO2-ODH) processes remains challenging, largely due to the difficulty of designing high-performance catalytic materials, particularly with respect to selectivity. In this context, the choice of support plays a critical role. Rather than merely acting as an inert carrier, it must enable high and stable dispersion of the active phase, typically based on Cr, Co, Zn, or Ga oxides, while preserving catalyst stability under harsh reaction conditions. Zeolites have recently attracted increasing interest because their crystalline porous structures combine high surface area with thermal and chemical stability. This review critically examines the literature on crystalline porous supports in CO2-ODH and discusses their potential advantages over other support classes in shaping catalyst dispersion, stability, and selectivity.