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Duffy, Emer; Krishnamurthy, Satheesh; He, Xiaoyun; Nesterenko, Ekaterina P.; Brabazon, Dermot; Nesterenko, Pavel N. and Paull, Brett
(2014).
Abstract
Porous graphitised carbon monoliths embedded with nanodiamonds (CMND) are presented in this work. Nanodiamond (ND) (sp3 carbon) has a variety of favourable properties including an interesting and tuneable surface chemistry, mechanical and thermal stability and conductivity. CMND was prepared using a hard templating method. Bare 5 μm silica particles and nanodiamonds (5-15 nm diameter) were added to the co-polymerisation mixture containing a resorcinol/iron(III) complex. Polymerisation of this mixture was followed by carbonisation at either 900 or 1250 °C under N2. Removal of the silica template and catalyst was achieved by hydrofluoric acid etching. A blank carbon monolith (CM blank) was also prepared using bare silica templates for comparative purposes.
BET surface area measurements showed CMND to have a higher specific surface area than CM blank (400 m2/g and 349 m2/g respectively, with carbonisation at 900 °C). HRTEM and FESEM characterisation of CMND revealed a variety of interesting carbon nanostructures to be present in the monolith following carbonisation at 1250 °C. Apparent onion-like carbon (OLC), carbon nano-rods up to several μm in length and graphene sheets were observed. OLC clusters can be produced by a temperature-induced transformation of ND. The temperature of carbonisation was critical in the formation of these carbon nano-structures, as were the localised heating effects resulting from the thermal conductivity of ND. Carbon nano-structures have high surface areas and a high sorption capacity making them suitable for a variety of prospective applications. Porous graphitic carbons are also receiving significant research interest due to their high surface areas and bimodal pore structure which make them ideal for use in a variety of applications including energy storage, as electrode materials or as adsorbents in solid phase extraction.