Effective toluene adsorption over defective UiO-66-NH2: An experimental and computational exploration

By Xiaoyu Shi, Xiaodong Zhang, Fukun Bi, Zenghui Zheng, Li Sheng, Jingcheng Xu, Z. Wang, Yiqiong Yang. 2020

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Abstract In this thesis, defective UiO-66-NH2 using cetyltrimethylammonium bromide (CTAB) as a template was successfully synthesized. The toluene adsorption-desorption properties were studied using breakthrough experiments and temperature programmed desorption (TPD). Modified UiO-66-NH2 showed a high toluene increase due to the increased specific surface area and total pore volume and extra accessible adsorption sites generated by defects. Additionally, adsorption mechanisms were discussed at micro and molecule levels in light of density functional theory (DFT) calculations. By calculation, the amino hydrogen bonding gave rise to a higher toluene adsorption over UiO-66-NH2. In terms of the modified UiO-66-NH2 with the most deficiencies, synergistic effects among π-π, -NH2, OH-CH3 and OH-π hydrogen bonding strength also significantly intensified toluene adsorption. Furthermore, it could be noted that the OH-π interaction was stronger than the two bonded μ3-OH mechanisms. Notably, TPD and binding energies (BEs) depicted that defective UiO-66-NH2 had a weaker toluene affinity than did UiO-66-NH2. Thus, gas toluene was easy to desorb with defective UiO-66-NH2 at 298 K under atmospheric pressure. Finally, the repetitive regeneration experiment showed that the reproducibility of the materials was excellent.

Subfields: Inorganic Chemistry, Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/664d647dc27dfac42d1efc6e5f399cf8603f7bc4