CO capture in hydrogen fuel cells
Deborah Durbin
Current global energy production relies primarily on fossil fuels; this leads to unsustainable energy practices that have significant negative environmental ramifications. Hydrogen fuel cells (HFCs) are an attractive replacement for fossil fuel combustion because they are more efficient and produce notably fewer contaminants. HFCs operate by converting the chemical energy stored in H2 bonds into electrical energy by oxidizing hydrogen before combining it with reduced oxygen, creating only water as a by-product. One of the major problems facing fuel cell use is carbon monoxide poisoning of the anode catalyst. Carbon monoxide (CO) is formed during fuel refining and then travels in the H2 feed gas into the fuel cell. Once in the cell, CO chemisorbs to the platinum catalyst much more strongly than H2. By this mechanism, CO occupies binding sites that would otherwise be used for hydrogen oxidation. The ideal solution to this problem is to remove CO from the H2 feed gas before it reaches the catalyst. Therefore, the present project focuses on the development of external graphene membranes that contain metal nanoparticles capable of capturing CO before it enters the fuel cell. If these membranes can be successfully produced, they will allow significantly lower loading of the expensive noble metal catalysts, thus decreasing the overall production cost of fuel cells while increasing efficiency and lifetime. Computational studies were performed on undoped or boron, nitrogen or oxygen-doped graphene containing nickel, platinum and iridium/gold particles at the Royal Military College of Canada. All doped systems showed a lot of promise, particularly those containing nickel. Electrochemistry and NMR experiments are underway at the University of Bristol to confirm these results.
Thank you to the Natural Sciences and Engineering Research Council of Canada for funding.
Contact: Deborah.Durbin@bris.ac.uk
