A research team at Case Western Reserve University has discovered that catalysts produced from carbon nanotubes immersed in a polymer solution have energy output equal to or more than platinum catalysts in fuel cells.
By using a correct combination of polymer and nanotube layout, the power output of the catalysts can be increased further, according to the researchers. The scientists used activated carbon nanotubes that are cheaper compared to platinum.
The researchers immersed the carbon nanotubes in a polymer polydiallyldimethylammoniumn chloride water solution for two hours. During the process, the polymer coats the surface of the nanotubes and attracts an electron partly from the carbon, generating a net positive charge. The scientists then positioned the nanotubes on the cathode side of an alkaline fuel cell where the charged material functions as a catalyst for the oxygen-reduction reaction, which generates electricity, while combining oxygen and hydrogen electrochemically.
According to the scientists, catalysts made of activated nanotubes have better stability and durability than platinum catalysts. The carbon-based catalyst exhibits longer catalytic activity and remains inert to the methanol’s crossover effect that decreases the activity of a catalyst made of platinum when the fuel transfers to the anode from the cathode.
The new method is based on the Dai lab's previous procedure in which carbon nanotubes immersed in nitrogen were utilized as a catalyst. In that method, nitrogen attracts electron from the carbon to generate a charge. Results demonstrated that the nitrogen-doped carbon nanotubes increased the energy output of platinum by three fold.