Enhancing the degradation efficiency of dimethyl nitrophenyl Phosphate, a chemical warfare agent Simulant, through acid sites in bimetallic Metal-Organic framework Ti-MOF-808(Zr): Synergistic roles of Lewis and Brønsted acids

Abstract

Nerve agents pose an immediate and severe threat to human health, emphasizing the critical need for catalysts that can rapidly and effectively degrade these agents. Herein, we synthesized Ti-MOF-808(Zr) materials with varying Ti/Zr molar ratio using microwave-assisted solvothermal method. Characterization techniques, including BET analysis, TEM, and TG-DTA, confirmed their outstanding properties, such as a high surface area (1756 m2/g), 100 nm particle size, cubic shape, and remarkable thermal stability exceeding 500 °C. The coexistence of Ti4+ and Zr4+ in the secondary building units or inorganic nodes significantly elevates the number of Lewis and Brønsted acid sites in the bimetallic Ti-MOF-808(Zr), as determined through the TPD-NH3 and FTIR-CD3CN methods. We harnessed the potential of MOF-808(Zr) and Ti-MOF-808(Zr) materials as catalysts for the swift degradation of dimethyl nitrophenyl phosphate (DMNP). Remarkably, 4 %Ti-MOF-808(Zr) could degrade DMNP with a half-life of 14.95 s, achieving a complete degradation time within 80 s. We conducted a comprehensive investigation into various factors affecting the DMNP degradation process, including the Ti/Zr molar ratio, catalyst mass, pH, and buffer solution concentration. Notably, our findings reveal that the efficiency of DMNP degradation is profoundly influenced by both the total number of Lewis acid sites and the average acid sites ratio.