Advances in the development of nanostructured catalysts based on carbon gels

• Carbon gels are produced by the carbonization of resorcinol–formaldehyde polymers.
• The conditions of gelation, drying and carbonization should be carefully controlled.
• The porosity and surface chemistry of carbon gels can be tailored.
• Supported or doped nanostructured carbon gels are prepared and successfully applied as catalysts.

Nanostructured carbon gels are prepared by sol–gel polymerization of resorcinol–formaldehyde. The flexibility of the sol–gel process permits the control of the morphology, porosity and surface chemistry of carbon gels, but a large amount of variables should be carefully fitted. Pure carbon gels used as supports or doped-carbon gels and organic–inorganic composites to be used as catalyst, can be prepared. When metal-doped carbon gels are prepared, metals are active in all synthesis steps: polymerization, carbonization and/or activation. Interactions between organic–inorganic phases determine the distribution/dispersion of metals, sintering resistance, porosity, graphitization, formation of different active phases, etc. thus offering a large amount of possibilities in catalysis because final metal particles are also active in many catalyzed processes. Metal-doped carbon gels are more resistant to sintering or leaching than impregnated catalysts, however, some metal particles are encapsulated by the organic matrix, being therefore inactive in catalysis. Relationships between chemical and physical parameters with catalysts characteristics: loading, accessibility, chemical nature, stability (leaching or sintering) and catalytic behavior of the supported active phases are discussed.

Figure optionsDownload high-quality image (239 K)Download as PowerPoint slide