Carbon nanotube boosting electrocatalytic oxygen evolution of NiFe-polyphenol coordination catalyst through donor-acceptor modulation.

Herein, we reported a facile strategy to prepare bimetal-polyphenol complexes coating on carbon nanotube (CNT) as a highly efficient OER catalyst. Tannic acid was used as an organic ligand to simultaneously coordinate with Ni and Fe ions and at the same time wrapped the surface of CNT. The obtained NiFe/TA@CNT catalyst showed superior catalytic activity with a low overpotential of 287 mV to reach the current density of 10 mA cm under a small Tafel slope of 70.24 mV dec and exhibited persistent stability in alkaline environment. Experimental results and density functional theory (DFT) calculations revealed that the electron transfer from CNT to NiFe/TA on the heterointerface modified the local electronic environment of the catalyst at atomic level and decreased the binding energies of adsorbed species, thus greatly accelerating the OER kinetic process and enhancing electrocatalytic activity.