Computation-aided design of oxygen-ligand-steered single-atom catalysts: Sewing unzipped carbon nanotubes

Abstract

Single-atom catalysts (SACs), among which nitrogen-doped graphene-supported SACs are successful models, have been extensively investigated for electrocatalysts. Although oxygen is a common impurity in graphene, metal-oxygen-based SACs are unutilized. Here, we devise a new type of oxygen-coordinated SAC (M-O-C) with a computation-aided approach. Theoretical modeling predicts that the metal atoms are strongly immobilized by carbonyl ligands in unzipped carbon nanotubes, and then the Ni-O-C SAC is synthesized for the oxygen evolution reaction (OER). It shows excellent OER activity with a low overpotential (228/325 mV at 10/100 mA cm−2), small Tafel slope (36 mV per decade), and long-term durability over 150 h. We find that the highly electronegative oxygen ligand deviates from the conventional linear scaling relationship by shifting toward a more reactive region, so the inductive effect of the oxygen ligand leads to superior OER activity. This “theory first followed by experiment” strategy would help in the design of various SACs.