FeCo-based hybrid MOF derived active species for effective oxygen evolution.

Metal-organic frameworks (MOFs) have been regarded as promising catalyst materials due to the richness of coordinately unsaturated metal sites on the surface, which can act as catalytic active centres. In this study, a hybrid MOF material composed of Fe-based MOF and Co-based MOF was prepared with the involvement of graphene oxide nanosheets as additive. It was demonstrated that the hybrid MOF materials showed much higher electro-catalytic activity towards oxygen evolution than the single-phase counterparts. To drive current density of 10 mA cm-2, the hybrid CoFe-based MOF only needed an over potential of 290 mV in 1 M KOH. The catalytic activity could sustain for a longer time with only slight current density decrease. During oxygen evolution operation, the MOF catalyst evolved into catalytic active species but kept well the microscale sheet-like structure. It is thus believed that this study will provide an avenue for the development of advanced electrocatalysts. Image 1 • Easy and cost-effective preparation of FeCo-based MOF nanosheets. • The MOF hybrid shows excellent catalytic activity toward oxygen evolution. • The MOF hybrid shows an overpotential of 290 mV at 10 mA cm-2 for oxygen evolution. • Long term catalytic performance stability was confirmed. • The MOF hybrid evolves into catalytic active species but keeps sheet-like structures. [ABSTRACT FROM AUTHOR]