Easy synthesis of ordered mesoporous carbon containing nickel nanoparticles by a low temperature hydrothermal method

Ordered mesoporous carbons (OMCs) with embedded metallic nickel (Ni) nanoparticles have been directly synthesized by a simple and low temperature (50 °C) hydrothermal method. The synthesis involved the use of a triblock copolymer Pluronic F127 as the mesostructure directing agent, resorcinol (R) and formaldehyde (F) as carbon precursors, and Ni(NO3)2·6H2O as nickel source. It consisted in the self-assembly of F127, Ni2+ salt and RF polymer in an acidic medium and further carbonization, where the Ni2+ was captured by the network of F127/RF and further reduced into metallic Ni nanoparticles. The resultant Ni/carbon materials were characterised by X-ray diffraction, thermogravimetric analysis, transmission electron microscopy and nitrogen sorption. Ni/carbon materials with a highly ordered mesostructure were obtained using equal moles of resorcinol and formaldehyde molar ratio (R/F = 1/1), whereas an excess amount of formaldehyde (R/F = 1/2) was found to not form an ordered carbon structure. The results showed that nickel particles, with sizes of ∼10–50 nm, were homogeneously dispersed in the carbon matrices, while the pore mesostructure remained intact. The homogeneous Ni/carbon composites synthesized by this easy hydrothermal route have been demonstrated to be effective molecular adsorbents for magnetic separation.