Synthesis of Three-Dimensional Mesostructured Graphitic Carbon Nitride Materials and their Application as Heterogeneous Catalysts for Knoevenagel Condensation Reactions

Three-dimensional (3D) mesostructured graphitic carbon nitride materials with tunable surface areas (394-498 m(2) g(-1)) and pore volumes (0.54-1.36 cm(3) g(-1)) were synthesized through a nanocasting method. Mesocellular silica foam (MCF) was used as a template, and carbon tetrachloride (CTC) and ethylenediamine (EDA) were used as precursors. The effect of the ratio of the two precursors (EDA/CTC) on the textural properties and chemical compositions of the CN-MCF samples were investigated by several characterization techniques. The results revealed that the 3D mesostructures were maintained when the ratio of EDA/CTC was greater than 0.4. Among the different CN-MCF materials prepared, CN-MCF-0.4 demonstrated the highest catalytic performance for Knoevenagel condensation reactions, mainly because of its high amount of surface N, high surface area, and large pore volume. In addition, the CN-MCF-0.4 catalyst showed good stability as well as versatility for various substrates. Mesostructured graphitic carbon nitride materials have been synthesized using MCF as template and the effects of the ratios of the N & C precursors on their physicochemical properties have been comparatively investigated; the materials demonstrate effective and versatile catalytic performance for a series of Knoevenagel condensation reactions.