Microwave-Assisted Solvothermal Synthesis of UiO-66-NH2 and Its Catalytic Performance toward the Hydrolysis of a Nerve Agent Simulant

Zenghui Zhang,Cheng-An Tao,Jianfang Wang,Fang Wang,Jie Zhao,Jian Huang

doi:10.3390/catal10091086

Abstract

Zr-containing metal-organic frameworks (MOFs) exhibit a good performance of catalyzing the hydrolysis of chemical warfare agents, which is closely related to the size of MOF particles and its defects, but these two factors are often intertwined. In this article, we synthesized UiO-66-NH2 nanoparticles using a microwave-assisted hydrothermal method. By using a new modulator 4-Fluoro-3-Formyl-Benzoic Acid (FFBA) in different proportions, MOF particles with the same defect degree but different scales and those with similar sizes but different defect degrees can be obtained. The performance of the obtained MOF particles to catalyze the hydrolysis of the nerve agent simulant, dimethyl 4-nitrophenyl phosphate (DMNP), was investigated, and the effects of single factors of size or defect were compared for the first time. As the size of the obtained MOF particles increased from 81 nm to 159 nm, the catalytic degradation efficiency toward DMNP gradually decreased, and the half-life increased from 3.9 min to 11.1 min. For MOFs that have similar crystal sizes, the catalytic degradation half-life of MOF3 is only 5 min, which is much smaller than that of MOF5 due to the defects increase from 1.2 to 1.8 per Zr6 cluster.

Highlights

Chemical warfare agents (CWAs) containing phosphonate ester bonds, which are named nerve agents, such as GA (Tabun), GB (Sarin), and GD (Soman), are among the most toxic chemicals known to mankind [1]
In order to confirm the success of the ratio of Fluoro-3-Formyl-Benzoic Acid (FFBA) to BDC-NH2 and the obtained solid products with the ratio of 10:0, 9:1, 7:3, and 5:5 were labelled as MOF0, MOF1, MOF3, and MOF5, respectively
In order to confirm the success of the synthesis of UiO-66-NH2, Powder X-ray diffraction (PXRD), Fourier transform infrared spectra

Summary

Introduction

Chemical warfare agents (CWAs) containing phosphonate ester bonds, which are named nerve agents, such as GA (Tabun), GB (Sarin), and GD (Soman), are among the most toxic chemicals known to mankind [1]. With the help of coordination bonds, MOFs can be assembled by metal ions or metal-oxygen clusters and organic bridging ligands [6,7] Benefiting from their excellent properties such as ordered and tunable pore sizes, high surface areas, abundant metal sites, and controllable chemistry microenvironment, certain MOFs have been demonstrated to be promising catalysts, which can catalyze the degradation of toxic nerve agents and their simulants (hydrolysis). They can even detoxify such a deadly substance in just a few minutes [8,9,10,11] by providing people with new protection against the threat of CWA

Results

Discussion

Conclusion