Engineering oxygen vacancies in CoO@Co₃O₄/C nanocomposites for enhanced electrochemical performances

Abstract

The build-in electric field derived from oxygen vacancy in Co-based electrocatalysts have become important for energy storage and conversion.

High-Entropy Oxide Derived from Metal–Organic Framework as a Bifunctional Electrocatalyst for Efficient Urea Oxidation and Oxygen Evolution Reactions

“…On the other hand, one effective strategy for improved electrocatalytic activity is defect engineering, for example, the occurrence of oxygen vacancies. 33 However, it is highly challenging to synthesize nanostructured HEOs rich in oxygen vacancies under low temperatures. 30,34 Therefore, the rational design of nanostructured HEOs with a large surface area at an optimum reaction condition to gain the benefits from the large surface area, appropriate size, and defect engineering remains challenging.…”

“…Another challenge in the synthesis of HEOs is achieving a high configurational entropy and preventing particle coarsening. On the other hand, one effective strategy for improved electrocatalytic activity is defect engineering, for example, the occurrence of oxygen vacancies . However, it is highly challenging to synthesize nanostructured HEOs rich in oxygen vacancies under low temperatures. , …”

Oxygen Vacancy‐Enriched Co3O4 as Efficient Co‐catalyst for Pt Nanoparticles towards Methanol Electrooxidation

“…As shown in Figure 4d, the rCo 3 O 4 ‐2 h displays a much stronger EPR signal (g=2.003) than pCo 3 O 4 , which is ascribed by singly ionized oxygen vacancies. Compared with pCo 3 O 4 , the oxygen vacancies of rCo 3 O 4 after NaBH 4 treatment are significantly increased [55–57] …”

“…Compared with pCo 3 O 4 , the oxygen vacancies of rCo 3 O 4 after NaBH 4 treatment are significantly increased. [55][56][57] To investigate the CO tolerance, CO stripping voltammograms have been measured in 0.5 M H 2 SO 4 solution (saturated with N 2 ). As exhibited in Figure 5 [58] The improved CO tolerance of PtÀ rCo 3 O 4 / C-2 h probably due to the next two reasons: (i) On the one hand, the powerful synergy between Pt and rCo 3 O 4 /C-2 h hybrid can lower the bonding energy of PtÀ CO. [38] (ii) On the other hand, the oxygen vacancy-enriched Co 3 O 4 can activate water molecules to generate plentiful OH ads species adsorbed on the catalyst surface, which could efficiently electro-oxidize to remove the CO adsorbed on the surface of Pt NPs.…”

Waste to Treasure: Regeneration of Porous Co-Based Catalysts from Spent LiCoO2 Cathode Materials for an Efficient Oxygen Evolution Reaction

“…29,30 As for the O 1s spectra (Figure 3d), the raw curves can be peak-fitted into three peaks located at 530.1, 531.7, and 533.8 eV, which can be assigned to the lattice oxygen (O L ) of Co−O, oxygen vacancies (O V ), and surface adsorbed hydroxyl groups, respectively. 24,31,32 In comparison to Co 3 O 4 , Co/Co 3 O 4 , and Co 9 S 8 /Co 3 O 4 show an obvious higher peak intensity at 531.7 eV, implying a significantly improved concentration of O V . The existence of O V can provide unsaturated coordination sites for accelerated charge transfer and enhanced conductivity of the catalysts, thus facilitating the OER electrochemical performance.…”