Review on Multidimensional Adsorbents for CO2 Capture from Ambient Air: Recent Advances and Future Perspectives

The urgency of curbing global warming triggered by growing CO2 emissions has generated significant attention. Direct air capture (DAC) is a crucial and feasible technology to cut CO2 emissions at nonpoint sources, therefore achieving negative emissions. Solid porous sorbents have drawn increasing attention for CO2 capture from the atmosphere with ultralow CO2 concentration (ca. 400 ppm). However, most related studies focus on nanoparticle-based adsorbents and their functionalized counterparts, which are more prone to lose weight in the atmosphere. In this context, we summarize nanoparticle composite adsorbents, including zero-dimensional powders, one-dimensional fibers, two-dimensional membranes, and three-dimensional aerogels, and assess the physicochemical properties and typical applications of major types of nanoporous adsorbents in the field of CO2 adsorption and separation with emphasis on DAC. The multidimensions of emerging adsorbents versus CO2 uptake are discussed and compared separately. Combined with recent reported advances, we provide deep insights for the design and synthesis of multifunctional materials for efficient CO2 adsorption. Moreover, life cycle and techno-economic assessments of DAC using different materials are briefly estimated. Finally, challenges and current trends in the DAC system for commercialization have been put forward.