Nanostructured carbon-metal hybrid aerogels from bacterial cellulose

Abstract

Infiltration of nickel(II) hydroxide inside a bacterial cellulose gel followed by thermal treatment gives rise to highly crystalline nickel nanoparticles that remain associated with the generated carbon nanofibers. The involved mechanism, ascribed to a carbothermal reduction, takes place at an exceptionally low temperature (390 °C). This study suggests the reduction of the intermediate nickel oxide phase by carbon and CO generated during pyrolysis of bacterial cellulose, while the nascent nickel nanoparticles catalyze the formation of graphitic carbon in the form of carbon aerogels. This synthesis route also generates equivalent carbon–iron hybrids pointing to the extension of this procedure to other transition metals as well, thus producing conducting carbon foams with functional metal nanoparticles. This soft procedure opens way to new carbon–metal aerogels with potential interest in fields as diverse as catalysis, energy storage and optical devices.