One-pot synthesis and assembly of melamine-based nanoparticles for microporous polymer organic frameworks and their application as a support for a silver nanoparticle catalyst

Abstract

A facile solvothermal method was developed for the one-pot synthesis of melamine-based nanoparticles and their subsequent assembly into microporous polymer organic frameworks (POFs), without the aid of catalysts or templates, using melamine and aromatic dialdehydes as the monomers. The structures and properties of the resulting materials were then systematically characterized by means of Fourier-transformed infrared (FTIR) spectroscopy, solid-state NMR, scanning electron microscopy (SEM) and N₂ adsorption isotherms. The results confirmed that the nanoparticles were constructed first and then assembled to form a porous structure with a broad distribution of pore size and high surface areas, which is ideal for a balance between the mass-transportation and active sites. Given the solvothermal conditions of 180 °C for 10 h, the as-prepared POFs possess intrinsic microporosity arising from highly cross-linked aminal networks, with specific surface areas of up to 718 m² g⁻¹ and pore volumes of up to 1.10 cm³ g⁻¹ at the molar ratio of 2 : 3 for melamine to terephthalaldehyde. The POF supported silver nanoparticles show an excellent catalytic performance for the degradation of methylene blue.