Fabrication Of Layered Metal-Organic Frameworks For Catalytic Degradation Of Chemical Warfare Agent Simulants

Detoxifying materials against chemical warfare agents（CWAs）and their simulants are highly desired for proper handling of contamination and destruction of CWAs.In this thesis,various strategies were used to fabricate layered metal-oraganic frameworks（layered MOFs）with different nanostructures and these layered MOFs were tested in hydrolytic catalysis of chemical warfare agent simulants.Our major work and conclusion were listed as follows.1.We first report the facile layer-by-layer fabrication of core-shell Fe₃O₄@UiO-66-NH₂ and its application in fast degradation of CWA simulant.The Fe₃O₄@UiO-66-NH₂ composite wasprepared through a layer-by-layer epitaxial growth strategy,by alternating immersing Fe₃O₄ nanoparticles in ethanol solution of metal node[Zr₆O₄（OH）₄]¹²⁺precursor and organic linkers[NH₂-BDC,2-aminoterephthalic acid]respectively and separating using a magnet.As confirmed by characterization results,the Fe₃O₄@UiO-66-NH₂ composites with24.4μmol/gof Zr₆ nodescontent show a well-defined core-shell structure as well as good thermal and chemical stability.Thesecore-shell magnetic MOFs were further tested in catalytic hydrolysis of DMNP（dimethyl-4-nitrophenyl phosphate,a nerve agent simulant）and demonstrated 30 times higher catalytic activity than UiO-66-NH₂ powder.Since magnetism is retained after the coating of MOF,Fe₃O₄@UiO-66-NH₂ could be easily recovered and reused after catalysis.2.We then fabricated free-standing 2D metal-organic layers（MOL）,Hf-BTB andZr-BTB[M₆O₄（OH）₄（HCOO）₆（BTB）₂]（M=Hf/Zr,BTB=1,3,5-Tris（4-carboxyphenyl）benzene）.By using microwave-assisted method,synthesis time was reduced to 1 h with high yields and 10-fold reaction scale.Two different modulators,fomic acid and concentrated hydrocholoric acid were chosen to modulate the synthesis.All the products were ultrathin layers with a thickness of 1～2 atomic layers.In further test of catalytic performance,the MOLs Hf-BTB-HCl and Zr-BTB-HCl showd outstanding efficicency with a t_1/2of 2.7 and 2.6 min and could reach 100%conversion in less than 30 min.This is among one of the best results reported and also the first report using Hf-MOFs against CWAs and simulants...