The work so far has concentrated on developing new methods by which the ADOR process can be applied, new materials that can be prepared and a study of the mechanisms. There has been significant progress in all three areas, split into four main activities.
In activity 1 we have prepared several new zeolites with interesting structures and also developed new methodology by which materials can be prepared using the approach. We have developed and published two new methodologies: the vapour phase transport (VPT) approach and mechanochemical synthesis. The VPT is essentially a gentler way to begin the ADOR process. In our original ADOR method the disassembly method used either pure water or a acidic solution. This worked well if the intermediate layers were stable to hydrolysis but not so well when there was any instability in the layers. Using vapour instead of liquid as the hydrolysis medium has allowed us to develop method that does not destroy all the layers during the process and so can be used to prepare new materials. Mechanochemical synthesis is a method by which the energy required for hydrolysis is produced by a mechanical grinding using a ball mill. We have used this method to show that the ADOR process can be utilised in this way too. Interestingly, the final product can be different from those using the traditional ADOR process. Recently, we have also developed the reverse ADOR process, which allows us to build up structural units between the layers in a way that has not been done before. This work is accepted for publication in Materials Advances
In activity 2 we are extending the ADOR work to a new type of porous material - metal-organic frameworks (MOFs). The ADOR process has not been applied to MOFs in the same way as it has for zeolites. We are therefore developing the procedures to allow us to do this. We have been successful in preparing a material called SIMOF-3 which is a pillared layer type material, and we can show how the pillars between the layer can be disassembled and replaced by other linkers (i.e. reassembled).
In activity 3 we are looking at the mechanism of the process itself in great detail, We have used X-ray diffraction, NMR and pair distribution function analysis to develop a greater insight into four steps in the process. This has produced some valuable information, which we have published in a series of papers, on the process itself but has also thrown up some interesting new aspects for both zeolite and MOF chemistry. In MOFs we have shown some unusual breathing behaviour of materials and in zeolites we have shown that the highly stable silica-based mateirals are in fact labile to water even at low temperatures. this was a significant suprise to the field and has significant consequences for how these important materials behave. This latter aspect is particularly important as it affects the way we view zeolites in contact with water. The ADOR process is founded on the hydrolysis of germanosilicates but the discovery that water has a more profound impact on the framework structure of zeolites is important
In Activity 4 we have been exploring the potential applications of both MOFs and zeolites, especially with respect to the catalytic properties of ADOR-derived zeolites and ideas behind microporous liquids (dispersions of nano particles in liquid). This has led to some new synthetic procedures of both MOFs and zeolites that are currerntly being developed, particularly in the area of physological gas transport for a range of different medical and biological application.
Dissemination: To the end of the reporting period (Mar 2025) we have published 32 papers and there are approximately 10 more in preparation.
