High-performance oxygen evolution catalyst using two-dimensional ultrathin metal-organic frameworks nanosheets

Synthesis of high-performance electrocatalysts is significant for energy conversions. The oxygen evolution reaction (OER) is a fundamental process in such energy conversions. Here, we first report the synthesis of NiFe-bimetal two-dimensional (2D) ultrathin metal-organic frameworks (MOFs) nanosheets (NiFe-UMNs) with a uniform thickness of ~10 nm, which show excellent catalytic activity for OER in alkaline conditions. The as-prepared NiFe-UMNs can deliver the current density of 10 mA cm−2 at a low overpotential of 260 mV. Moreover, NiFe-UMNs possess by far the lowest Tafel slope of 30 mV dec−1 for OER. The high-performance activity is the result of abundant surface coordinatively unsaturated metal atoms, as well as the addition of Fe that is also crucial to enhance the activity.