Nanoporous materials such as zeolites and metal-organic frameworks (MOFs) are highly tailorable. Their structure diversity and tunability allow us to fine-tune these materials for the selective sorption of different gases. Pore size tuning, in particular, is an effective way to design sorbents with very high selectivity in the sorption of greenhouse gases such as SF6 and CO2. Depending on the target gas, different approaches towards pore size tuning are needed to yield sorbents with good sorption properties. Some examples of pore size tuning on zeolites (NaKA) and MOFs (ZIF-7-8, UU-200-204, and KAUST-7) will be presented here. Novel approaches to utilizing solid physisorbents for CO2 capture will also be discussed.
Understanding mixed-metal oxides CO2 sorbents: mixed-metal oxides, specifically, Na2ZrO3, is a well-known high-temperature CO2 sorbent. The CO2 capture capability of Na2ZrO3 is believed to depend on its crystal structure. Hexagonal Na2ZrO3 is known to be more stable, and monoclinic Na2ZrO3 is known for its high CO2 uptake. However, the two polymorphs have an identical number of peaks in the PXRD pattern?