Over the last decade UNM has been involved in the design of Platinum Group Metal-free (PGM-free) anode catalysts for the emerging field of Alkaline Membrane Fuel Cells (AMFC). Initial effort was directed towards catalysts for selective hydrazine oxidation.^1-3 These series materials were based on allowing Ni with oxophillic metal (Zn, La, etc.) to enhance hydrazine dehydrogenation step in contrast to N-N bond splitting as a base for much desired catalyst selectivity.^{4, 5} These Ni-based electrocatalysts were further designed to include Ni alloys with refractive metals⁶ (Mo, W, Cr) and demonstrated exceptional dehydrogenation selectivity, thus creating the base for the development hydrogen oxidation catalysts in alkaline media. The nickel-based electrocatalysts were synthesized as nanoparticles supported on various carbon blacks and modified carbon blacks with loadings of up to 50 % wt. (see Figure A & B). Synthesized martials were comprehensively characterized by physical-chemical methods: XRD, BET, SEM, TEM and XPS. Electrochemical activity of the catalysts was studied with Rotating Disk Electrode (RDE) technique and in a single membrane electrode assembly (MEA) AMFC. MEA design was optimized with respect to critical fabrication parameters such as: catalyst layer thickness (loading), catalyst-to-ionomer ratio, and catalyst deposition as Catalyst Coated Membrane (CCM) vs. gas-diffusion electrode (GDE). It was found that NiMo/C electrocatalyst has a mass activity similar to palladium supported on carbon.⁷ The MEA performance obtained in H₂/O₂ single MEA fuel cell tests using Tokuyama membrane and ionomer reached a peak power density higher than 120 mW.cm^-2 at relative humidity (RH) of 70 %. When Ni_0.9Cu_0.1 supported on Ketjen Black catalysts was used (see Figure C), a record high peak power density was demonstrated: up to 350 mW.cm^-2. These new nickel-transition metal alloy catalysts are being studied in detail by spectroscopy and modeled by DFT to establish relevant structure-to-property correlation and demonstrate their utility in H₂/O₂ AEMFC.

Acknowledgement: DOE-EERE FCTO, Incubator Program DE-EE0006962 “Development of PGM-free Catalysts for Hydrogen Oxidation Reaction in Alkaline Media” (Alexey Serov, PI).

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