Fe-Based Electrocatalysts for Oxygen Evolution Reaction: Progress and Perspectives

Abstract

Electrocatalytic oxygen evolution reaction (OER) is a core reaction responsible for converting renewable electricity into storable fuels; yet, it is kinetically challenging, because of the complex proton-coupled multielectron transfer process. Transition-metal-based electrocatalysts, which provide the possibility for the realization of low-cost, high-activity, and stable OER in alkaline solution, therefore have attracted significant research interest in recent years. A fundamental understanding of composition–structure–activity relationships for these electrocatalysts is essential to guide the design of practical electrocatalysts for industrial applications. With more advanced ex situ and in situ techniques to determine the active sites, there has been increasing evidence revealing the critical role of Fe in the high performance of Fe-containing transition metal-based electrocatalysts. Here, we present a critical review of recent progress in Fe-containing electrocatalysts for OER, highlighting the significant role of Fe in enhancing the OER activity. We outline the historical development of the Fe-containing electrocatalysts, summarize the conflicting viewpoints on catalytic active sites, and offer guidelines for more rigorous identification. The synthesis techniques and the major challenges in improving the intrinsic catalytic activity and stability are discussed. Finally, a perspective regarding emerging issues yet to be explored for developing OER electrocatalysts for practical applications are also provided.

Strong Electronic Interaction Enhanced Electrocatalysis of Metal Sulfide Clusters Embedded Metal–Organic Framework Ultrathin Nanosheets toward Highly Efficient Overall Water Splitting

“…[54,55] Recent research further suggests that the OER activity of Ni/Febased catalyst could be enhanced by strengthening the adsorption of oxygenated intermediates such as *OH and *O on the surface. [54,56,57] Fe/Ni centers at electron-rich state are conducive to enhance the oxygenated intermediates for accelerated OER kinetics, [58][59][60] which is confirmed by the lower Tafel slope and smaller R ct of NiFe-MS/MOF@NF compared to NiFe-MOF@NF in present work as shown in Figure 4c,d. Therefore, the higher intrinsic OER activity of NiFe-MS/MOF@NF originates from the higher electron density on its metal sites, as a consequence of incorporation of metal sulfide clusters.…”

A soft molecular 2Fe–2As precursor approach to the synthesis of nanostructured FeAs for efficient electrocatalytic water oxidation

“…First, the semiconductor nature of the two-line ferrihydrite [96][97][98] contributes to the high OER electrocatalytic activity, in contrast to the non-conducting FeO x H y phases. [99][100][101][102] Second, it is also possible that the in situ formation of the new phase may induce some defective edges/sites which could behave as active centers during catalysis, which would explain its higher OER activity. [103][104][105][106] Additionally, the surface of 2-line ferrihydrite is enriched with tetrahedrally coordinated Fe 3+ atoms, that can serve as active sites for the OER.…”

Controlled Assembly of Cu/Co‐Oxide Beaded Nanoclusters on Thiolated Graphene Oxide Nanosheets for High‐Performance Oxygen Evolution Catalysts

“…for OER for alkaline electrolyzers. [9][10][11][12] Moreover,t heir hybrid materials with various conducting substrate, that is, carbon nanotubes (CNT), graphene oxide (GO), and heteroatom-doped carbon have also been extensivelye xplored to further enhance their catalytic potential. [13,14] Among all these materials, metal oxidesb ased electrocatalysts are still the leadingc atalysts owing to their high redox potential for OER and inherently tunable orbital energy levels and active sites.…”