Decoupling Surface Area and Detoxification Performance in UiO-66-NH2: Critical Role of Micropore Accessibility Enabled by Microwave-Controlled Synthesis

Abstract

UiO-66-NH2 is an effective material for detoxifying chemical warfare agents (CWAs) due to its high stability and porous structure. In this study, the effects of synthesis parameters on the structural and functional properties of UiO-66-NH2 were systematically investigated using a microwave-assisted approach, which enables rapid crystallization but requires precise control of synthesis parameters within a narrow processing window. Key variables, including reaction time, temperature, modulator concentration, and postsynthetic drying conditions, were controlled to evaluate their effects on the morphology, crystallinity, and porosity of UiO-66-NH2. Comprehensive characterization revealed that modulator-assisted synthesis and optimized activation conditions significantly improved particle size, structural ordering, and accessible microporosity. The optimized sample exhibited well-defined polyhedral crystals and a high Brunauer–Emmett–Teller surface area of 859 m2 g–1. These results highlight that microwave-assisted synthesis operates within a narrow processing window, where precise control of conditions is essential. The detoxification performance was evaluated using a nerve agent simulant under solvent-free (dry) conditions. The optimized sample exhibited excellent performance, achieving approximately 85% degradation of a nerve-agent simulant within 30 min. In contrast, the sample with the largest measured surface area exhibited negligible detoxification activity, suggesting that surface area alone does not reliably predict performance under dry conditions. Instead, the detoxification efficiency appears to be influenced by the accessibility of intrinsic micropores and active sites, as well as the structural integrity of the framework. These findings highlight the importance of controlling the synthesis and activation conditions within microwave-assisted processes and provide a fundamental design principle for metal–organic framework-based detoxification materials in practical solvent-free environments.