Oxidized g-C3N4 Nanospheres as Catalytically Photoactive Linkers in MOF/g-C3N4 Composite of Hierarchical Pore Structure

A unique composite of the copper-based metal-organic framework (Cu-benzene tricarboxylic acid (BTC)) with oxidized graphitic carbon nitride nanospheres is synthesized. For comparison, a hybrid material consisting of g-C3N4 and Cu-BTC is also obtained. Their surface features are analyzed using Fourier transform infrared spectroscopy, X-ray diffraction, sorption of nitrogen, thermal analysis, scanning electron microscopy, photoluminescence, and diffuse reflectance UV-Vis spectroscopy. The results suggest that the formed nanospheres of oxidized g-C3N4 act as linkers between the copper sites, playing a crucial role in the composite building process. Their incorporation to the Cu-BTC framework causes the development of new mesoporosity. Remarkable alterations in the optical properties, as a result of the coordination of oxygen containing functional groups of the oxidized graphitic carbon nitride to the copper atoms of the framework, suggest an increase in photoreactivity. On the other hand, for the hybrid material consisting of Cu-BTC and g-C3N4, the unaltered pore volume and optical properties support the formation of a physical mixture rather than of a composite. The tests on reactive adsorption and detoxification of G-series organophosphate nerve agent surrogate show the enhanced performance of the composite as catalysts and photocatalyst in visible light.