Among different materials, zeolites have well-defined pores at nanoscale. They are attractive for shape-selective catalysis, and are widely used in industry, producing basic chemicals. Recently, zeolites have drawn huge interests in CO2 capture, removal of harmful gases from automobiles, as well as biomass conversion.
However, although millions of different zeolites can theoretically exist, there are only hundreds that has been made so far, presumably due to the lack of rationale for synthesis.
Now, Xiaodong Zou and Zhehao Huang from the Stockholm University, Suk Bong Hong and Seungwan Seo from the Pohang University of Science and Technology, Robert Bell from the University College London and colleagues have found a new way in generating novel zeolites. The results have been published in the journal Nature Communications.
Material revealed at atomic level
The first step in this discovery was the structure solution of a zeolite, which was first made in the last decade, but its structure remained unknown. Using an advanced technique called continuous rotation electron diffraction recently developed by the same team, the material was revealed at an atomic level.
“Using electron diffraction is the key leads to the discovery”, says Zhehao Huang, who is the major contributor to the new findings. “At first, we are curious about the unknown structure. After seeing the atoms using electron diffraction, we realized immediately that there is something unusual”.
In fact, the atomic structure is closely associated to another zeolite made by the same team. A phenomenon, known as 3D-3D topotactic transformation, was therefore discovered. After the transformation, a totally different zeolite, which has a distinct channel system, was obtained.
Generate new materials from existing ones
By exploiting the transformation, the team found that this can be a general top-down approach to generate new materials from existing ones. They have made predictions of a series of new zeolites that can be made by this approach but may not feasible with conventional methods. Theoretical study conducted by the team proved that all the predicted materials are synthetically feasible.
“We are excited”, says Xiaodong Zou, who is a leading scientist in the project. “Making new zeolites is critical for expanding their applications. Still, the new ones are mainly synthesized by trial and error. Our finding made an important step towards targeted synthesis, which can help find desired zeolites, and enrich the diversity”.
This work was supported by the Swedish Research Council (VR), the Knut and Alice Wallenberg Foundation (KAW), the National Research Foundation of Korea and the National Research Council of Science & Technology of Korea.
Article in Nature Communications 3D-3D topotactic transformation in aluminophosphate molecular sieves and its implication in new zeolite structure generation.
For further information
Xiaodong Zou, Professor in Inorganic and Structural Chemistry, Department of Materials and Environmental Chemistry, Stockholm University. Mobile 076-2168820, E-mail: xzou@mmk.su.se
