Advances in solid adsorbent materials for direct air capture of CO<sub>2</sub>

Direct air capture (DAC) of CO2 is a carbon-negative technology that is not limited by time and geography and can contribute to the realization of the “dual-carbon” goal. In this paper, the current development of direct air capture of CO2 is reviewed, focusing on four mainstream solid adsorption DAC technologies, namely, metal-organic frameworks (MOFs), solid amine materials, alkali-metal-based adsorbents, and moisture-altering materials, and their advantages and disadvantages in terms of energy consumption, cyclic stability, and adsorption capacity are analyzed. In addition, the engineering applications of solid adsorbent materials are analyzed and the potential of these technologies in practical applications is demonstrated. Finally, the challenges faced by existing DAC adsorbent materials are summarized and the future development direction is put forward.