Dual Promoting Effects of Hereditary Mn Doping and Oxygen Vacancies on Porous CuCo₂O₄ for Electrocatalytic Oxygen Generation

Abstract

It is well known that the oxygen evolution reaction (OER) is predominant to restrict hydrogen production efficiency from water splitting. Herein, a porous spinel oxide, CuCo 2 O 4 , with abundant defects is successfully developed via a facile strategy (alloying−dealloying−annealing) as an efficient and economical electrocatalyst for OER. Profiting from the well-structured porosity, cation defects (Cu vacancies) induced by hereditary Mn doping, and anion defects (oxygen vacancies), O V -np-Cu 10 Co 20 (Mn) gives a smaller OER overpotential of 310 mV at 10 mA cm −2 and admirable long-term stability. Under the simulated industrial conditions (60 °C, 6 M KOH), this demands a cell voltage of 1.71 V to reach 500 mA cm −2 , as well as exhibits a slight attenuation of voltage after a chronopotentiometric test over 80 h. Density functional theory (DFT) calculations uncover that Mn doping could elongate the Cu−O bond, increase the electronic states near the Fermi level, and optimize the d-band center position of CuCo 2 O 4 . With the help of moderate oxygen vacancies (O V ), the energy barrier of the rate-determining step can be further reduced to 2.69 eV. This work tactfully takes advantage of the Mn element to not only construct nanoporous skeletons but also modulate electronic structures, paving an easy route to fabricate defect-enriched porous spinel oxides and accelerate the exploitation of the cost-effective OER electrocatalyst.

Advanced MnOx/MnWO4 hetero-nanoflakes with abundant oxygen vacancies for high-performance flexible asymmetric supercapacitors with high energy density

“…In addition, the higher content of Mo 3+ means the higher oxygen vacancy content. 29–31 Fig. 3d shows the high-resolution O 1s spectra of MnO x /MnWO 4 @C-3 composites, which reveal three typical peaks at 530.87, 532.37 and 530.35 eV, representing lattice oxygen (O1), oxygen vacancy (O2) and oxygen species adsorbed on the surface (O3), respectively.…”

NiFe-Based Semi-MOF Embedded by Sulfide Particles Reconstructed a Three-Layer Sandwich Structure for Alkaline Overall Water Splitting

“…Splitting water via electricity achieves zero carbon emissions with its easily available hydrogen source (water molecules) and no harmful byproducts, providing an eco-friendly energy production technology. The oxygen evolution reaction (OER), one of the half-reactions of overall water splitting (OWS), is a sluggish four-electron–proton coupling process that requires more energy to reduce the kinetic barrier, leading to the development of advanced catalysts to drive it. , Unfortunately, the wide application of the most efficient noble-metal-based catalysts such as RuO 2 and IrO 2 has been restricted on account of their low reserves and high costs, and bifunctional non-noble-metal catalysts for both the cathode and anode are rare. Therefore, research on an affordable and earth-abundant transition metal compound (TMC) electrocatalyst (such as layered double hydroxide, nitride, phosphate, , sulfide, and selenide) as a substitute for noble metal is of great significance to solve the problem of global energy demand and environmental degradation …”

Construction of Binder‐Free, Self‐Supported, Hetero‐Core–Shell Honeycomb Structured CuCo2O4@Ni0.5Co0.5(OH)2 with Abundant Mesopores and High Conductivity for High‐Performance Energy Storage

“…In addition, the multicomponent metal oxides have flexible and adjustable electronic band structures, [ 51 ] and the spinel structure in CCO@N 0.5 C 0.5 OH/NF has a narrow energy bandgap (≈ 0.35 eV) [ 37 ] and abundant localized electrons. [ 52 ] The unique electronic structure enables CCO@N 0.5 C 0.5 OH/NF possess a fast electron mobility, which is of excellent value for both electrocatalysis and electrochemical energy storage. [ 52 ]…”

“…[ 52 ] The unique electronic structure enables CCO@N 0.5 C 0.5 OH/NF possess a fast electron mobility, which is of excellent value for both electrocatalysis and electrochemical energy storage. [ 52 ]…”