Nitrogen-doped carbon as selectively permeable layer to enhance the anti-poisoning ability of hydrogen oxidation reaction catalysts for hydroxide exchange membrane fuel cells

Abstract

The use of platinum group metals (PGMs) as the catalysts and the requirement of high purity H2 are the two aspects resulting in the high cost of the polymer electrolyte membrane fuel cells. Herein, we report that nitrogen-doped carbon encapsulated nickel nanoparticles (Ni@NC) as stable hydrogen oxidation reaction catalysts, which allows the use of PGM-free anode catalysts durably and feeding crude hydrogen. The hydroxide exchange membrane fuel cell using Ni@NC as the anode catalyst illustrates steady performance for more than 200 h, while the Ni/C cell fails within 7 h. The current density loss is less than 10% by feeding H2 with 100 ppm of CO for 24 h, which is much better than those using Pt/C or Ni/C. The anti-poisoning feature is attributed to the block effect of the NC shell, while the defects allow the permeation of H2, thus catalyzing the hydrogen oxidation reaction.