Elevating the d-Band Center of Six-Coordinated Octahedrons in Co_9S_8 through Fe-Incorporated Topochemical Deintercalation

摘要

Significant efforts have been dedicated to boosting the electrocatalytic activity of Co9S8 for the oxygen evolution reaction (OER); however, with limited improvement in its intrinsic activity, which relies on careful band engineering. Fe possesses one less 3d electron and lower electronegativity than Co, suggesting a higher d-band center when forming polyhedron with S anions. Here, to improve the intrinsic activity by elevating the d-band center, the six-coordinated octahedrons in Co9S8 are redesigned utilizing an Fe-incorporated topochemical deintercalation method. Through substituting partial Co octahedrons by Fe octahedrons with higher d-band, the overall d-band center is regulated to achieve optimized adsorption and thus superior OER activity. With a reduction of 95 mV on the overpotential (at 10 mA cm(-2)), this work sheds lights on the design of OER catalysts through polyhedron engineering using topochemical deintercalation.