Bottom-Up Synthesis of Anatase Nanoparticles with Graphene Domains

Using alizarin and titanium isopropoxide, we have succeeded in preparing a hybrid form of nanostructured graphene–TiO₂ following a bottom-up synthetic approach. This novel graphene-based composite offers a practical alternative to synthesizing photocatalytically active materials with maximized graphene–TiO₂ interface. The molecular precursor alizarin was chosen because it efficiently binds to TiO₂ through the hydroxyl groups and already possesses the graphene building block through its anthracene basis. XPS and Raman spectroscopy proved that the calcined material contained majority sp²-hybridized carbon that formed graphene-like clusters. XRD data showed the integrated structures maintained their anatase crystallography, therefore preserving the material’s properties without going through phase transitions to rutile. The enhanced graphene and TiO₂ interface was confirmed using DFT computational techniques. The photocatalytic activity of the graphene–TiO₂ materials was demonstrated through degradation of methylene blue

In Situ Probes of Capture and Decomposition of Chemical Warfare Agent Simulants by Zr-Based Metal Organic Frameworks

Zr-based metal organic frameworks (MOFs) have been recently shown to be among the fastest catalysts of nerve-agent hydrolysis in solution. We report a detailed study of the adsorption and decomposition of a nerve-agent simulant, dimethyl methyl­phosphonate (DMMP), on UiO-66, UiO-67, MOF-808, and NU-1000 using synchrotron-based X-ray powder diffraction, X-ray absorption, and infrared spectroscopy, which reveals key aspects of the reaction mechanism. The diffraction measurements indicate that all four MOFs adsorb DMMP (introduced at atmospheric pressures through a flow of helium or air) within the pore space. In addition, the combination of X-ray absorption and infrared spectra suggests direct coordination of DMMP to the Zr₆ cores of all MOFs, which ultimately leads to decomposition to phosphonate products. These experimental probes into the mechanism of adsorption and decomposition of chemical warfare agent simulants on Zr-based MOFs open new opportunities in rational design of new and superior decontamination materials