Reducing energy barriers by multi-interface design on MXene with confined Fe-doped CoSe2 for ultra-efficient OER electrocatalysis

Abstract

To design multi-heterointerfaces for doping-type electrocatalysts is a promising strategy to synergistically balance the catalytic activity/durability. In this study, we report a dual-MOFs/MXene composite derivation strategy to construct porous N-doped carbon encapsulating Fe-doped CoSe2 on both sides of MXene (Fe-CoSe2@PNC/TC). Combining multi-characterizations and density functional theory calculations, the Fe doping and well-designed multi-interfaces can induce the internal Se vacancy and electronic structure modulation, increasing and enhancing the active sites and, thus, reducing energy barriers for oxygen evolution reaction (OER). Thereby, the OER activities of Fe-CoSe2@PNC/TC powder materials have been significantly improved, which exhibits an overpotential of only 244 mV to attain 10 mA cm−2 with the long-term durability and a ultra-small Tafel slope of 41.1 mV dec−1 in 1.0 M KOH electrolyte (No IR correction), far outperforming the benchmark of commercial IrO2. This work proposes a controllable route combining multi-interface design and heteroatom doping for ultra-efficient OER electrocatalysis.

Construction of amorphous/crystalline Fe doped CoSe for effective electrocatalytic oxygen evolution

“…10 Dou et al 11 introduced Fe dopants and Co vacancies into atomic thick CoSe 2 nanoribbons for the OER, and CoSe 2 –D Fe –V Co exhibited high catalytic activity. Yuan et al 12 constructed porous N-doped carbon encapsulated Fe-doped CoSe 2 (Fe-CoSe 2 @PNC/TC) on both sides of MXene, where Fe doping and well-designed multifacets can induce internal Se vacancies and electronic structure modulation to increase and enhance the active sites, thus lowering the energy barrier for the OER. The OER activity of the Fe-CoSe 2 @PNC/TC powder material was significantly improved, far better than that of the commercial IrO 2 .…”