[Purposes] This study investigates the CO₂ adsorption performance of porous geopolymers prepared using the ice templating method, aiming to provide a novel approach for the preparation of CO₂ adsorbents and further broaden the application scope of geopolymers. [Methods] Using water glass and slag as fundamental raw materials, porous geopolymers were synthesized through the ice templating technique. The pore structure was characterized using mercury porosimetry and N2 adsorption/desorption analysis. The CO₂ adsorption performance was investigated employing thermal analysis instrumentation. [Findings] Porous geopolymers prepared using the ice templating method exhibit a trimodal distribution of pore sizes, ranging from nanometers to a few micrometers, and up to several hundred micrometers. The mesoporous structure demonstrates a layered arrangement. The CO₂ adsorption capacity of the porous geopolymers reaches 4.07 mmol/g. The adsorption process follows a pseudo-second-order kinetic model, with physical and chemical accounted for 7.28% and 92.72% of the total adsorption respectively. [Conclusions] Compared to other CO₂ adsorbents, the porous geopolymers produced through the ice templating method exhibit a higher CO₂ adsorption capacity. Considering the inherent high-temperature resistance and excellent chemical stability of geopolymers, these materials hold the potential for applications in specific environmental conditions. They represent a highly promising CO₂ adsorption material with notable prospects.