Effect of Interfacial Strength and Anchoring in a Highly Efficient NiTe₂/NF@CuFe Oxygen-Evolution Catalyst

Abstract

Morphology and electronic-structure modulation are of widespread interest when designing oxygen-evolution-reaction (OER) electrocatalysts for use in fuel cells. In this study, we prepared a NiTe2/NF@CuFe catalyst using replacement reactions and hydrothermal reduction. NiTe2-nanoparticle morphology was adjusted by the introduction of multiple Fe centers and Cu replacement, which resulted in a NiTe2/NF@CuFe catalyst that exhibited excellent OER performance. The thus-prepared catalyst showed a low overpotential of 228 mV and a Tafel slope of 33 mV dec–1 at 10 mA cm–2 in 1 M KOH as the electrolyte. The catalyst is remarkably stable compared to the reference catalyst during electrocatalytic oxygen evolution over 12 h. Density function theory calculations confirmed that the Cu atoms not only facilitate neighboring charge-transfer processes but also build isolated areas of NiTe2 nanoparticles. Net charges and the electron localization function reveal that the well-distributed doped Fe atoms significantly stabilize the NiTe2 nanoparticles on the surface and improve its electronic activity during the OER process. This work provides an effective concept for the synthesis of highly efficient overall water-splitting electrocatalysts.

A copper interface promotes the transformation of nickel hydroxide into high-valent nickel for an efficient oxygen evolution reaction

“…To understand the contribution of ECSA to the catalytic activity, we measured the electrochemical doublelayer capacitance (C dl ) of each electrode, as the C dl value is proportional to the ECSA. 41,42 As shown in Fig. S5, † the C dl values of NF, Cu/NF, Ni(OH) 2 /NF, and Ni(OH) 2 /Cu/NF were 5.6 mF cm −2 , 10.9 mF cm −2 , 10.5 mF cm −2 , and 27.3 mF cm −2 , respectively.…”

“…Overall, the large surface area and high content of NiOOH active species make the Ni(OH) 2 /Cu/NF electrode one of the best Ni-based catalysts so far reported (Table S2 †). 38,41,[43][44][45][46][47][48][49] Furthermore, it also shows excellent stability for the OER (Fig. 5d).…”