Ni₃N as an Active Hydrogen Oxidation Reaction Catalyst in Alkaline Medium

Abstract

Hydroxide‐exchange membrane fuel cells can potentially utilize platinum‐group‐metal (PGM)‐free electrocatalysts, offering cost and scalability advantages over more developed proton‐exchange membrane fuel cells. However, there is a lack of non‐precious electrocatalysts that are active and stable for the hydrogen oxidation reaction (HOR) relevant to hydroxide‐exchange membrane fuel cells. Here we report the discovery and development of Ni3N as an active and robust HOR catalyst in alkaline medium. A supported version of the catalyst, Ni3N/C, exhibits by far the highest mass activity and break‐down potential for a PGM‐free catalyst. The catalyst also exhibits Pt‐like activity for hydrogen evolution reaction (HER) in alkaline medium. Spectroscopy data reveal a downshift of the Ni d band going from Ni to Ni3N and interfacial charge transfer from Ni3N to the carbon support. These properties weaken the binding energy of hydrogen and oxygen species, resulting in remarkable HOR activity and stability.

Regulating electronic structure of two‐dimensional porous Ni/Ni3N nanosheets architecture by Co atomic incorporation boosts alkaline water splitting

“…Furthermore, synchrotron‐based X‐ray absorption spectroscopy (XAS) and ultraviolet‐photoelectron spectra (UPS) were conducted to investigate the electronic properties of Co–Ni/Ni 3 N. The white line at 8354 eV in the Ni K‐edge X‐ray absorption near edge structure (XANES) spectra matches well with the previously reported Ni 3 N (Figure 2D). 50 The adsorption edges of Co–Ni/Ni 3 N and Ni 3 N locate between Ni foil and NiO, suggesting average value states of Ni element are between 0 and +2, which is in consistent with the XPS Ni 2p results. Moreover, the pre‐edge peak of Ni K‐edge changes to a higher intensity, suggesting the increased Ni oxidation state and electron transfer occurs as the incorporation of Co 15,51 .…”

Nonprecious transition metal nitrides as efficient oxygen reduction electrocatalysts for alkaline fuel cells

“…S4, E to H), the spectra displayed characteristic spin-orbit splitting (2p 3/2 versus 2p 1/2 ). The components at low binding energies (low oxidation state) can be described as metal-nitrogen (M-N) bonding as they displayed metallic behavior (45). The emergence of spectral features at higher binding energies suggested the formation of oxides/hydroxides or oxynitrides arising from spontaneous surface oxidation.…”

High-Performance Ru 2 P Anodic Catalyst for Alkaline Polymer Electrolyte Fuel Cells

“…6 As an alternative to PEMFCs, alkaline polymer electrolyte fuel cells (APEFCs) have received considerable attention by virtue of the development of nonnoblemetal-based electrocatalysts with Pt-like stability and high activity in cathode for ORR in alkaline electrolytes. 4,7,8 However, the kinetics of anodic HOR in alkaline solution, even for the most advanced Pt-based catalysts, are approximately two to three orders of magnitude more sluggish than in acidic solution, 9,10 which means that more Pt-based catalysts are required to overcome the sluggish anodic HOR in APEFCs. Consequently, developing Pt-free materials as highly active and stable anodic catalysts for APEFCs is highly desirable.…”

“…19,20 Despite the fact that some Ni-based nonprecious metal electrocatalysts have been reported for catalyzing alkaline HOR, their catalytic performances are still far below the practical application in APEFCs. 4,[6][7][8]21,22 Most of the APEFCs with Ni-based materials as the anodes only show the peak power density around 0.1 W cm −2 . [22][23][24] As the cheapest metal in the platinum group of metals (PGM), Ru-based electrocatalysts have received considerable attention.…”