Neighboring Site Synergies in Co-Defective Ru–Co Spinel Oxide toward Oxygen Evolution Reaction

Abstract

As is well known that the oxygen evolution reaction (OER) is dominant to determine water splitting, regulating the electronic structure of the electrocatalyst has been demonstrated to be an effective strategy for improving OER activity. Herein, Ru− Co spinel oxides with abundant cobalt vacancies (V Co -RCO) are successfully developed as a highly efficient electrocatalyst for OER. Interestingly, the introduction of Ru can induce the formation of cobalt vacancies, which can modulate the electronic state of V Co -RCO, optimizing the location of the d-band center and generating neighboring Ru−Co synergies, thereby improving the OER catalytic activity. As a result, the V Co -RCO exhibits a small overpotential of 240 mV at 10 mA/cm 2 , which is more advanced than that of Co 3 O 4 , RCO without defect, and various RuO 2 catalysts. The in situ Raman analysis and density functional theory calculations further confirm the neighboring Ru−Co synergies of V Co -RCO, and this mechanism can not only facilitate fast electron transfer between Ru and Co sites through the bridging OOH but also reduce the adsorption strength of OER intermediates, leading to a significant enhancement of OER catalytic activity.

3D Hierarchical MOF-Derived Defect-Rich NiFe Spinel Ferrite as a Highly Efficient Electrocatalyst for Oxygen Redox Reactions in Zinc–Air Batteries

“…The satellite peaks at 720.1 and 730.7 eV further imply the presence of Fe 2+ and Fe 3+ in the electrocatalysts in their prepared state. Results of the XPS analysis showed that Fe substitution caused the generation of cation defects. , Predictably, Fe 2+ and Fe 3+ species were discovered in Ni 0.6 Fe 2.4 O 4 @NC- 1 . This discovery occurred due to the electronic interaction of the Fe and Ni atoms.…”

“…Results of the XPS analysis showed that Fe substitution caused the generation of cation defects. 57 , 58 Predictably, Fe 2+ and Fe 3+ species were discovered in Ni 0.6 Fe 2.4 O 4 @NC- 1 . This discovery occurred due to the electronic interaction of the Fe and Ni atoms.…”

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

“…Liu's group 11 synthesized a new Zn x Ni 1−x Co 2 O 4 /NCNTs composite via the hydrothermal process, in which Zn 2+ substitution could not only afford larger specific surface area and enough structured edge but also produce Zn vacancies (V Zn ), allowing more correct interactions between Co adsorption sites and oxygen-containing intermediates. Pan et al 12 found that Ru doping was made for forming Co vacancies (V Co ), which can regulate the electronic structure of V Co -RCO and generate synergistic effects between Ru and Co, as well as improve the electrocatalytic performance toward OER. As can be seen, larger atom doping is prone to induce cation defects in host materials that could facilitate charge delocalization and reduce overpotentials of electrocatalytic reactions.…”