Carbon Dispersion and Morphology in Carbon-Coated Nanocrystalline MgO

Nanoscale carbon/MgO composite adsorbents have been prepared by chemical vapor deposition (CVD) of carbon over aerogel-prepared nanocrystalline MgO with propylene as the carbon precursor, and by pyrolysis of Mg(OH)2 aerogels modified with resorcinol. A new textural approach including adsorption methods and HREM has been applied for comprehensive characterization of their textural properties. Carbon has been found to form twisted isolated graphite-like fragments designated as nanoislands (1−2 graphite-like monolayers) coating the MgO surface in the case of carbon CVD and a thicker (2−3 graphite-like monolayers) coating in the case of pyrolysis of resorcinol-modified Mg(OH)2 aerogels. The average number of carbon nanoislands grows with an increase of carbon loading whereas their mean size remains approximately the same. The nanoislands have very high specific surface areas close to the maximum surface area possible for carbon. The discovered peculiarities of carbon deposition allow one to achieve controlled...