Boosting the Electrocatalytic Water Oxidation Performance of CoFe₂O₄ Nanoparticles by Surface Defect Engineering

Abstract

Spinel oxides have attracted widespread interest for electrocatalytic applications owing to their unique crystal structure and properties. The surface structure of spinel oxides significantly influences the electrocatalytic performance of spinel oxides. Herein, we report a Li reduction strategy that can quickly tune the surface structure of CoFe 2 O 4 (CFO) nanoparticles and optimize its electrocatalytic oxygen evolution reaction (OER) performance. Results show that a large number of defective domains have been successfully introduced at the surface of CFO nanopowders after Li reduction treatment. The defective CFO nanoparticles demonstrate significantly improved electrocatalytic OER activity. The OER potential observed a negative shift from 1.605 to 1.513 V at 10 mA cm −2 , whereas the Tafel slope is greatly decreased to 42.1 mV dec −1 after 4 wt % Li reduction treatment. This efficient Li reduction strategy can also be applied to engineer the surface defect structure of other material systems and broaden their applications.

Oxygen‐Defect‐Rich Cobalt Ferrite Nanoparticles for Practical Water Electrolysis with High Activity and Durability

“…[30,31] Earlier reportso nC oFe 2 O 4 have employed external modulations, such as introducing as econdary phase or Ndopedc arbon supports, [23,32] since single-phase ferrites are less celebrated as electrocatalysts for water dissociation. Therea re few reports on defecte ngineering in CoFe 2 O 4 nanoparticles (NPs) by Li reduction treatment for water oxidation, [33] and in CoFe 2 O 4 nanosheets by NaBH 4 reduction for overall water splitting. [34] On the contrary,h erein, the physical properties of pristine CoFe 2 O 4 NPs are altered by tuning the oxygen vacanciesa sa functiono fp article size, which,i nt urn, increases the number of electrochemically active sites and lowers the free energyo f adsorption for enhanced performance towards OER/HERh alfreactionsa nd overall alkaline and seawater splitting.…”

Investigation of mixed-metal (oxy)fluorides as a new class of water oxidation electrocatalysts

“…3 The highest performing class of these OER catalysts is oen iron based oxides/oxyhydroxides containing Ni or Co, and in select cases, these 3d metal oxides outperform the precious metal standards. 4,5 The presence of strain, 6 defects, 7,8 and dopants 9 as well as exfoliation 10 and an amorphous structure 11 have been shown to further boost the performance of metal oxides. We point the interested reader to several recent reviews and perspectives on metal-oxide OER catalysts.…”

Mesoporous NiFe2O4 with Tunable Pore Morphology for Electrocatalytic Water Oxidation

“…[33] Due to the variety of parameters influencing the formation and activity of mesoporous electrocatalysts, detailed studies are necessary to understand the structure/activity relationships of mesoporous electrocatalysts. [34] Since many transition metal oxides are intrinsically poorly conductive, [35,36] shortening the diffusion pathways by nano-/mesostructuring can improve the transport of charge carriers through the material.…”