Behavior, mechanisms, and applications of low-concentration CO2 in energy media

This review explores the behavior of low-concentration CO₂ (LCC) in various energy media, such as solid adsorbents, liquid absorbents, and catalytic surfaces. It delves into the mechanisms of diffusion, adsorption, and catalytic reactions, while analyzing the potential applications and challenges of these properties in technologies like air separation, compressed gas energy storage, and CO₂ catalytic conversion. Given the current lack of comprehensive analyses, especially those encompassing multiscale studies of LCC behavior, this review aims to provide a theoretical foundation and data support for optimizing CO₂ capture, storage, and conversion technologies, as well as guidance for the development and application of new materials. By summarizing recent advancements in LCC separation techniques (e.g., cryogenic air separation and direct air carbon capture) and catalytic conversion technologies (including thermal catalysis, electrochemical catalysis, photocatalysis, plasma catalysis, and biocatalysis), this review highlights their importance in achieving carbon neutrality. It also discusses the challenges and future directions of these technologies. The findings emphasize that advancing the efficient utilization of LCC not only enhances CO₂ reduction and resource utilization efficiency, promoting the development of clean energy technologies, but also provides an economically and environmentally viable solution for addressing global climate change.