Investigation of Nitrogen-Rich Carbon Nitride Networks as Redox-Active Metal Catalyst Support Materials.

摘要

This one-year feasibility study was designed to examine the thermal, chemical, and electrochemical properties of novel nitrogen-rich carbon nitride (C(sub 3)N(sub 4+x)) network materials for use as catalysts in proton exchange membrane (PEM) fuel cell electrodes. We have produced carbon nitride materials and carbon composites thereof; particularly we discovered a rapid, facile method to make carbon nitride carbon black composites in a single step. This in- situ method is an effective strategy to produce homogeneous electrically conducting composite materials. As expected, the electrical conductivity of the semiconducting carbon nitride greatly improves when it is mixed with conducting carbon black. We have determined that carbon nitride and its composites with carbon black are electrochemically inert in neutral and acidic environments and do not impede oxidation-reduction reactions. Catalytically active metals were deposited onto the carbon nitride powders using solution and hydrogen reduction strategies. Platinum metal containing carbon nitrides showed appreciable electroactivity in O2, CO and methanol aqueous environments. In some cases, the current densities achieved for these Pt-carbon nitride composites exceed those observed for Pt on carbon obtained from commercial sources. Other metal catalysts such as Ni also showed promising electrochemical events in O2, CO, and methanol environments.