Hydrogen oxidation reaction catalysts derived from Co, Ni-coordination compounds and polymers (MOFs)

Abstract

Aiming to obtain catalysts for the Hydrogen Oxidation Reaction (HOR) and to construct fuel cells completely free of noble metals, two Ni-MOFs, a Ni-coordination polymer, and a Ni-complex were synthesized, together with their corresponding Co and NiCo analogs. The following N-heterocyclic ligands were employed: 2-Methylimidazolate, imidazolate, nicotinate, 2,3-pyrazinedicarboxylate and pyrazinecarboxylate. These precursor compounds were pyrolyzed at 700 °C obtaining metallic nanoparticles embedded within N-doped mesoporous carbons. These materials were characterized by different physical and electrochemical techniques. The catalysts exhibited HOR activities (jη = 50 mv) comparable to the best-reported materials, i.e.: 1.3 and 0.6 mA cm−2disk for the Ni imidazolate and Ni nicotinate derived materials respectively. The results are relevant for the design of new catalysts and to construct alkaline anion exchange membrane fuel cells completely free of platinum group metals.