(293g) Nickel-Based Anode Catalysts for Efficient and Affordable Hydroxide Exchange Membrane Fuel Cells

Hydroxide exchange membrane fuel cells (HEMFCs), because of the alkaline environment that permits the use of platinum group metal (PGM)-free catalysts, have become an alternative technology with inherent long-term cost advantages. However, the development of PGM-free catalysts for anodic hydrogen oxidation reaction (HOR) has lagged behind, presumably owing to its sluggish kinetics in alkali. Since Raney nickel (Ni) was explored for alkaline HOR catalysis in 1960s, research on Ni-based HOR catalysts has begun and now is flourishing, majorly thanks to their favorable adsorption energies of key HOR intermediates (e.g., Ni-H_ad and Ni-OH_ad). At present, a number of strategies have been developed to improve HOR performances of Ni-based materials, such as alloying, Ni nitridation, and alloy amorphization, which yield cost-effective HOR catalysts that rival, or even exceed, the activity and stability of PGM counterparts.

In this talk, I will describe our recent research endeavors toward the development of efficient Ni-based HOR catalysts for practical HEMFC anodes. First, we briefly highlight the important merits of HEMFC technology and why Ni-based materials are appealing for alkaline HOR catalysis. Critical innovations in the design of Ni-based nanostructured and bulky catalysts were then discussed, showing their great promise to catalyze alkaline HOR that traditionally relied on PGMs. To demonstrate utility, performances of the elaborately designed Ni-based catalysts under realistic fuel-cell conditions were examined, along with an initial effort to develop CO-tolerant HEMFC anode. I will conclude this talk by outlining future research directions that allow access to next-generation PGM-free HOR catalysts for advanced HEMFCs.