(678e) New Strategies of Enhancing Steam Stability of MOFs By Modification with Post-Synthesis and in-Situ Synthesis Methods

 Jing Xiao^1*, Zhedong Lin, Hao Li, Xin Zhou, and Zhong Li^{2, *}

1 School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China

2 The Key Laboratory of Enhanced Heat Transfer and Energy Conversation Ministry of Education, South China University of Technology, Guangzhou 510640, PR China

* Presenting authors: cejingxiao@scut.edu.cn; cezhli@scut.edu.cn

ABSTRACT

MOFs are very potential materials for gas adsorption and separation due to their ultrahigh surface area, open crystalline structure and adjustable chemical functionality. Unfortunately, most of MOFs are unstable under humid circumstances, which greatly hinders their practical applications. Thus, enhancing water vapor stability of MOFs is a very challenging issue in research community. Here, we reported two strategies to enhance the steam stability of Cu-BTC (HKUST-1). Cu-BTCs were functionalized with some organic compounds to prepare TED@Cu-BTC and ACN@Cu-BTC separately by in-situ synthesis method and post-synthesis method, and then characterized. Water vapor stability and CO₂ adsorption capacity of the resulting samples were examined. Results show that the resulting samples possessed similar crystal structure and textural parameters as well as CO₂ capacity as the parent Cu-BTC. More interestingly, the water vapor stability of the resultant samples were significantly enhanced in comparison with Cu-BTC. Steam stability experiments proved that after being exposed to moist air with relative humidity of 80% for 20-30 days, the resulting samples preserved their main crystal structures and 80% of its initial CO₂ capacity, and in contrast, the parent Cu-BTC almost lost its crystallinity and its CO₂ adsorption capacity. The origination of the improved steam stabilities of the modified Cu-BTC were interpreted by DFT calculations. The strategy of incorporating TED and ACN into Cu-BTC is very efficient in improving its stability against moisture, which is worthy of further exploitation for enhancing stream stability of some MOFs.