Characterization of FeS₂-Based Thin Films as Model Catalysts for the Oxygen Reduction Reaction

Abstract

FeS 2 and (Fe,Co)S 2 thin films prepared by magnetron sputtering have been investigated as model catalysts for the oxygen reduction reaction (ORR), and their activities were compared against that of a sputtered thin film of Pt. Scanning Auger microscopy (SAM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and micro-Raman spectroscopy have been used, in parallel with electrochemical activity measurements using the thin film as a rotating disk electrode (RDE), to assess how the electrochemical performances of the sulfide films relate to chemical composition and structure. Comparisons were also made against a mineral FeS 2 pyrite whose open circuit potential (OCP) was 0.62 V and much less than the values of 0.78 and 0.80 V found for the FeS 2 and (Fe,Co)S 2 thin films, respectively (all potentials are given vs the reversible hydrogen electrode). There are indications that the ORR activities for these films may be associated with the presence of some polysulfides in addition to the expected S 2 2bulk and surface sites.

Carbon‐Supported CoSe2 Nanoparticles for Oxygen Reduction Reaction in Acid Medium

“…Yet, the reason has been unknown. The onset potential is comparable to the OCP value of non-precious metal ORR catalysts recently reported by Campbell and his coauthors (see Introduction section) [28][29][30]. On the other hand, the cathodic current density ca.…”

Microwave Synthesis of High Activity FeSe2/C Catalyst toward Oxygen Reduction Reaction

“…Oxygen reduction reaction (ORR) is an important process in an electrochemical energy conversion and a four-electron reaction is desirable to take place for a given catalyst in order to achieve good electrocatalytic performance. In recent years, the transition metals such as Mn [2], Fe [3,4], Co [5], Ni [6], Cu [7] and the heteroatom dopants B [8], N [9,10], P [11,12], S [13,14], Se [15] have been reported to modify the catalytic properties of various carbon materials including amorphous carbon, carbon nanotubes, and graphene, which arouse a great deal of interest for the research and development of non-noble catalysts.…”

What Can We Learn in Electrocatalysis, from Nanoparticulated Precious and/or Non-Precious Catalytic Centers Interacting with Their Support?

“…Some data from the literature were 2.0 mA·cm −2 for Co 1−x Se/C (50 wt % Cobalt on Vulcan carbon) [96], and 2.5 mA·cm −2 for (Co, Ni)S 2 thin films [98] at 2000 rpm. The OCP value of 0.81 V in oxygen-saturated 0.5 M H 2 SO 4 surpassed the Co 1−x Se/C [96], and FeS 2 (0.78 V) [97]. The OCP was quite similar to that of NiS 2 (0.80 V), and CoS 2 (0.82 V) [98], but not better than that of (Co, Ni)S 2 (0.89 V) [98].…”

“…2.5 mA·cm −2 at 0.4 V at 1600 rpm) [96][97][98]. Some data from the literature were 2.0 mA·cm −2 for Co 1−x Se/C (50 wt % Cobalt on Vulcan carbon) [96], and 2.5 mA·cm −2 for (Co, Ni)S 2 thin films [98] at 2000 rpm.…”