Understanding the Structure-Property Relationships in Nanoporous Materials

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Our research will focus on nanoporous materials including zeolites and metal-organic frameworks (MOFs). These materials have been applied in industry for catalysis, ion-exchange, gas separation/purification, drug delivery and sensing. Characterization is important because understanding the relationships between the properties of these materials and their unique structures is crucial for improving current uses and developing future applications in industry and technology. ******1. Formation of zeolites ***(i) To design new zeolites for novel applications, we must better understand how zeolites form under hydrothermal synthesis conditions. To achieve this goal, we will perform an in-situ study using solid-state nuclear magnetic resonance (SSNMR), which will allow us to monitor the complex zeolite formation process in real time under the actual conditions of high temperatures and pressures. (ii) Alkyl ammonium cations and neutral amines are used as structure directing agents (SDAs) in zeolite synthesis. The exact role of these SDAs is still not clear. We will use 14N SSNMR to follow the evolution of the SDA local environment during crystallization, allowing us to understand how a SDA helps form a particular framework. (iii) We will use mechanical force (pressure) and mechanochemistry as new routes for synthesizing new zeolites, based on assembly-disassembly-organization-reassembly (ADOR) approach. The outcomes of the aforementioned studies will enhance our ability to design new zeolites with specific properties for targeted applications.******2. Characterization of gas adsorption in MOFs***(i) The capture and storage of the greenhouse gas CO2 is tremendously important to combat climate change. MOFs are particularly suitable for this application. We will use SSNMR to examine adsorbed CO2 behaviour in MOFs under humid conditions. As water always exists in industrial CO2 sources, the emphasis will be on investigating the effect of water on CO2 adsorption. The results will allow us to design new water-stable MOFs with high CO2 adsorption capabilities in the presence of moisture for greenhouse gas storage. (ii) Natural gas (NG, mainly CH4) is an abundant, favourable alternative to conventional liquid hydrocarbons for automobile fuel, because CH4 combustion yields less CO2 for each unit of heat released. We will investigate CH4 adsorption in MOFs, which are promising solid adsorbents for NG storage. This work will improve CH4 adsorption ability in MOFs for vehicular applications. (iii) Hydrogen (H2) fuel cells are another clean energy source, and MOFs are promising H2 storage media. H2 storage capacity can be improved by tuning MOF properties via post-synthetic modification. We will develop new strategies of introducing additional metal ions inside the MOFs to increase their H2 adsorption ability. The outcome of these projects will lay the foundation for designing better MOFs for gas storage.