The catalytic reduction of carbon dioxide to carbon onion particles by platinum catalysts

摘要

Since their discovery, carbon nanomaterials 1 have attracted a great deal of interest from many research groups worldwide, since they exhibit unique chemical and physical properties 2. Both carbon nanotubes (CNT) and carbon onion particles (COP) have been prepared by a variety of methods that can be classified into two broad categories: physical and chemical. These techniques have been reviewed recently 3, the physical methods include electric arc discharge synthesis, laser ablation, resistivity vaporization, electron or ion beam vaporization and sunlight vaporization. The chemical methods are, for example, the catalytic pyrolysis reactions of hydrocarbons, catalytic disproportion of carbon monoxide (CO) 4,5, the reduction of perfluorinated hydrocarbons by an alkali metal amalgam, hydrothermal growth from amorphous carbon, catalytic reduction of CO and the thermal decomposition of Fe(CO)_5 in a flow of CO 6, Among the chemical methods there are two reports for the use of carbon dioxide (CO_2) as a carbon source to produce carbon nanomaterials, both of which use supercritical CO_2, one with melted metallic magnesium at 1000 deg C and a pressure of 10,000 atm 7 and the other one with melted metallic lithium at 550 deg C and a pressure of 700 atm 8.