Ir/Ni-NiO/CNT composites as effective electrocatalysts for hydrogen oxidation

Developing highly efficient non-Pt hydrogen oxidation (HOR) catalysts for use in alkaline solution is very important for anion-exchange membrane hydrogen-oxygen fuel cells. Herein, Ir/Ni-NiO/CNT composite catalysts were designed and prepared, in which carbon nanotubes (CNTs) were used as the support and iridium nanoparticles were anchored on the surface of Ni-NiO. In alkaline media, the as-prepared Ir/Ni-NiO/CNT catalyst exhibited excellent catalytic performance with a mass activity of 1.59 mA mu g(Ir)(-1) for HOR, which is superior to that of Ir/CNT and even commercial Pt/C catalysts. Experimental and theoretical calculation studies showed that the presence of Ni-NiO weakened the hydrogen binding energy on Ir sites, which facilitated the Volmer step for HOR and thus improved the catalytic activity.