An efficient nickel hydrogen oxidation catalyst for hydroxide exchange membrane fuel cells

Abstract

The hydroxide exchange membrane fuel cell (HEMFC) is a promising energy conversion technology but is limited by the need for platinum group metal (PGM) electrocatalysts, especially for the hydrogen oxidation reaction (HOR). Here we report a Ni-based HOR catalyst that exhibits an electrochemical surface area-normalized exchange current density of 70 μA cm–2, the highest among PGM-free catalysts. The catalyst comprises Ni nanoparticles embedded in a nitrogen-doped carbon support. According to X-ray and ultraviolet photoelectron spectroscopy as well as H2 chemisorption data, the electronic interaction between the Ni nanoparticles and the support leads to balanced hydrogen and hydroxide binding energies, which are the likely origin of the catalyst’s high activity. PGM-free HEMFCs employing this Ni-based HOR catalyst give a peak power density of 488 mW cm–2, up to 6.4 times higher than previous best-performing analogous HEMFCs. This work demonstrates the feasibility of efficient PGM-free HEMFCs. Hydroxide exchange membrane fuel cells are promising as an energy conversion technology, but require platinum group metal electrocatalysts for their application. A Ni-based hydrogen oxidation reaction catalyst is now shown to exhibit unprecedented electrochemical performance.