Ultrathin supported graphite oxide and carbon films

A wet colloid-chemical synthetic method is considered as a new approach to supported nanostructured graphite oxide (GO) and carbon films. The films are prepared by self-assembly from aqueous colloids of chemically exfoliated GO onto substrates of different nature: Al2O3; MgO; ZnO; Si; GdSi (42% Si) powders fumed silica and a Si plate containing surface nanostructured Si layer. The procedure works on both planar and high surface area substrates. It was found by X-ray diffraction and X-ray photon spectroscopy analysis that the chemical nature of substrate surface, in particular its basicity, determines the structure and particles orientation of the GO layer whose thickness increases with an increase of GO concentration in the starting suspension. Thermal treatment of the GO films leads to GO decomposition and the formation of supported carbon films. The GO deposition has been shown to increase 8-30 times the adsorption capacity of the substrates toward Cu(II) amino complexes. The GO film adsorption capacity can be controlled by varying GO concentration of the starting suspension. The maximum GO adsorption capacity (24 mmol g(-1)) is observed for the samples which were prepared using the suspensions with GO concentration of 0.3-0.4 gl (-1), and is close to the total quantity of oxygen-containing groups in GO. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.