CO2-Assisted synthesis of a crystalline/amorphous NiFe-MOF heterostructure for high-efficiency electrocatalytic water oxidation

Modulating the crystalline phase and structure of metal organic frameworks (MOFs) for superior electrocatalytic oxygen evolution reaction (OER) performance is a significant but challenging topic. Herein, a facile CO2-assisted strategy is reported to fabricate a crystalline/amorphous NiFe-based MOF heterostructure (c/a-NiFe-MOF) that exhibited excellent OER performance with a low overpotential of only 236 mV at a current density of 10 mA cm-2 and a small Tafel slope of 30 mV dec-1. This work provides new insights for CO2-assisted preparation of novel MOF heterostructures with diverse crystalline phases and sheds light on the rational design of highly efficient OER electrocatalysts.