Efficient Hydrogen Oxidation Catalyzed by Strain-Engineered Nickel Nanoparticles.

The hydroxide-exchange membrane fuel cell (HEMFC) is a promising energy conversion device. However, the development of HEMFC is hampered by the lack of platinum-group-metal-free (PGM-free) electrocatalysts for the hydrogen oxidation reaction (HOR). Now, a Ni catalyst is reported that exhibits the highest mass activity in HOR for a PGM-free catalyst as well as excellent activity in the hydrogen evolution reaction (HER). This catalyst, Ni-H2 -2 %, was optimized through pyrolysis of a Ni-containing metal-organic framework precursor under a mixed N2 /H2 atmosphere, which yielded carbon-supported Ni nanoparticles with different levels of strains. The Ni-H2 -2 % catalyst has an optimal level of strain, which leads to an optimal hydrogen binding energy and a high number of active sites.