Fe incorporation-induced electronic modification of Co-tannic acid complex nanoflowers for high-performance water oxidation

Abstract

The exploration of high-efficiency, cost-effective and Earth-abundant non-noble metal electrocatalysts toward the oxygen evolution reaction (OER) is of vital importance for the advancement of renewable energy conversion technologies. Herein, we report a feasible one-step hydrothermal method to synthesize Fe-doped Co-tannic acid coordination complex nanoflowers (denoted as Fe_xCo_1−x-TA nanoflowers). It is experimentally proved that moderate Fe incorporation could effectively generate abundant O vacancies, expose more active sites and modulate the electronic structure, therefore promoting the OER activity. To be specific, the harvested Fe_0.15Co_0.85-TA catalyst with the optimal Fe doping content exhibits an excellent OER performance in an alkaline medium with a low overpotential of 272 mV at 10 mA cm⁻², a small Tafel slope of 53.9 mV dec⁻¹ and a faradaic efficiency of nearly 100%. This cation-doping strategy for the regulation of the electronic structure toward the performance improvement of transition metal coordination complexes is immensely instructive for the future design of affordable and efficient electrocatalysts for various renewable energy conversion systems.