A new type of efficient CO₂ adsorbent with improved thermal stability: Self-assembled nanohybrids with optimized microporosity and gas adsorption functions

A new type of efficient CO₂ absorbent with improved thermal stability is synthesized via self-assembly between 2D inorganic nanosheets and two kinds of 0D inorganic nanoclusters. In these self-assembled nanohybrids, the nanoclusters of CdO and Cr₂O₃ are commonly interstratified with layered titanate nanosheets, leading to the formation of highly microporous pillared structure with increased basicity of pore wall. The co-pillaring of basic CdO with Cr₂O₃ is fairly effective at increasing a proportion of micropores and reactivity for CO₂ molecules and at improving the thermal stability of the resulting porous structure. Of prime importance is that the present inorganic-pillared nanohybrids show highly efficient CO₂ adsorption capacity, which is much superior to those of many other absorbents and compatible to those of CO₂ adsorbing metal-organic framework (MOF) compounds. Taking into account an excellent thermal stability of the present nanohybrids, these materials are very promising CO₂ adsorbents usable at elevated temperature. This is the first example of efficient CO₂ adsorbent from pillared materials. The co-pillaring of basic metal oxide nanoclusters employed in this study can provide a very powerful way of developing thermally stable CO₂ adsorbents from many known pillared systems.