Interface Electronic Coupling in Hierarchical FeLDH(FeCo)/Co(OH)₂ Arrays for Efficient Electrocatalytic Oxygen Evolution

Abstract

The oxygen evolution reaction (OER) with sluggish kinetics is the key half‐cell reaction for several sustainable energy systems, such as electrochemical water splitting, fuel cells, and rechargeable metal–air batteries. Two‐dimensional transition‐metal hydroxides have good prospects for the OER. Herein, 2D hierarchical FeLDH(FeCo)/Co(OH)2 (LDH=layered double hydroxide) arrays were fabricated by growing 2D‐ZIF‐67 (ZIF=zeolitic imidazolate framework) on carbon cloth, transformation of 2D‐ZIF‐67 into Co(OH)2, and electrodeposition of FeLDH(FeCo) on Co(OH)2 at ambient temperature. The optimized hierarchical catalyst exhibits high OER activity that requires a small overpotential of only 242 mV to drive 10 mA cm−2 (279 mV for 100 mA cm−2) and prolonged durability for 100 h at 20 mA cm−2 in 1 m KOH. The FeLDH(FeCo)/Co(OH)2 interfaces are observed to be the electrocatalytically active centers for the OER. The interfaces contribute to accelerating the OER kinetics owing to fast transfer of intermediate oxygen species. Furthermore, the FeCo alloy promotes electron transfer among the newly formed interfaces related to CoOOH in the OER process, which leads to improved durability. This work gives insight into the design and synthesis of hierarchical bimetallic hydroxide arrays with high OER activity and durability, as well as understanding of the origin of the OER promotion by metals and metal hydroxides.

2D Layered Double Hydroxide Nanosheets and Their Derivatives Toward Efficient Oxygen Evolution Reaction

“…The fabrication of heterojunctions in catalyst would be a new strategy to promote their catalytic activities by purposefully regulating the electronic structure of active sites. For the past few years, many other 3D hierarchical nanoarrays on conductive 3D networks, such as CoFe LDH/Co 0.85 Se/carbon cloth, NiFe LDH@NiFe-Bi/carbon cloth, and NiSe/NiFe LDH/Ni foam, have been reported as high-performance OER catalysts [139][140][141][142][143][144].…”

High-Performance Zinc–Air Batteries with Scalable Metal–Organic Frameworks and Platinum Carbon Black Bifunctional Catalysts

“…Diminished intensity of the satellite peak at about 786 eV, which is attributed to the Co 2+ oxidation state in ZIF-67, indicates the increased concentration of Co 3+ by formation of amorphous cobalthydroxide phase at the expense of Co-N coordination. 24,34,[44][45][46][47] Deconvolution of Co 2p 1/2 and Co 2p 3/2 peaks confirms existence of Co 2+ (peaks at ~798 and 781.2 eV) and Co 3+ (peaks at ~795.5 and ~779.9 eV). 33,34,[36][37][38]48 This is also evidenced in O 1s spectra, which show three peaks at 532.3, 531.5 and 530.4 eV, corresponding to adsorbed water (H 2 O), hydroxy oxygen (O H ) and metal-O, respectively.…”

“…All these support for a formation of amorphous Co(OH) 2 nanosheets from in-situ degradation of ZIF-67 structure. 34,[44][45][46][47] XPS spectra closely reveal new structure development and interaction between cobalt-related nanophase and platinum nanoparticles (Figure 5h-j). For instance, a shift in the Co 2p peak to lower binding energy is seen in a sample after ORR durability test compared to initial ZIF-67@Pt/CB.…”

In‐Situ Activated NiFePBA‐FeOOH Electrocatalyst for Oxygen Evolution Reaction and Zinc‐Air Battery

“…And the synergistic effect between in‐situ activated nickel and ion oxyhydroxides enhances OER performance with small overpotential, small Tafel slope and durable stability. At the same time, the as‐prepared NiFePBA‐FeOOH composite exhibits outstanding catalytic performance than other previously reported Ni‐based, Fe‐based and Co‐based catalysts such as CoFePBA, NiFeMOF, FeLDH(FeCo)/Co(OH) 2 , NiFeTiOOH, CoOOH, FeOOH and MoFe:Ni(OH) 2 /NiOOH, as shown in Figure 5a [4,11,23,25,26,31,34,41–44] . Herein, practically applying exploration of homemade zinc‐air battery (ZAB) is assembled with NiFePBA‐FeOOH catalyst for OER mixing commercial 20 % Pt/C for ORR (labeled as Pt/C+NiFePBA‐FeOOH) due to the lacking ORR performance of NiFePBA‐FeOOH catalyst.…”

“…At the same time, the as-prepared NiFePBA-FeOOH composite exhibits outstanding catalytic performance than other previously reported Ni-based, Fe-based and Co-based catalysts such as CoFePBA, NiFeMOF, FeLDH(FeCo)/Co(OH) 2 , NiFeTiOOH, CoOOH, FeOOH and MoFe:Ni(OH) 2 /NiOOH, as shown in Figure 5a. [4,11,23,25,26,31,34,[41][42][43][44]…”