Tuning oxygen vacancies in two-dimensional iron-cobalt oxide nanosheets through hydrogenation for enhanced oxygen evolution activity

Simultaneous Modulation of Composition and Oxygen Vacancies on Hierarchical ZnCo2O4/Co3O4/NC‐CNT Mesoporous Dodecahedron for Enhanced Oxygen Evolution Reaction

“…[54,56] DFT calculations have suggestedt hat the existence of oxygen vacancies could decrease the hindrance of the adsorption of H 2 O/OH À at low-coordination Co 3 + sites. [54,57] The optimized ZnCo 2 O 4 /Co 3 O 4 /NC-CNT-700 sample also shows comparable activity for the OER among the as-prepared catalysts, commercial IrO 2 ,a nd ar ecently reported reference catalyst ( Table S3 in the Supporting Information). The OER performance of different catalysts was further evaluated in terms of their Ta fel slopes ( Figure 4B and Figure S7 Bi nt he Supporting Information), whicha re usually employed to understand the reaction kinetics and mechanismso fd ifferent catalysts.…”

“…The incorporation of Zn 2+ into the Co 3 O 4 lattices could increase the length of Co 3+ −O bonds, which would promote OH − adsorption onto Co 3+ , and thus, facilitate the formation of Co 4+ sites and enhance the OER catalytic activity . The integration of oxygen vacancies, composition, and interface synergistic effects could promote the formation of CoOOH, but an understanding of the OER mechanism is challenging due to multiple‐electron transfer in the OER . In addition to catalytic activity, stability is another important criterion to consider for catalysts.…”

“…The integration of oxygen vacancies, optimal composition, and interface synergistic effects between ZnCo 2 O 4 and Co 3 O 4 in ZnCo 2 O 4 /Co 3 O 4 /NC‐CNT‐ X could play more critical roles in activation of the catalytic sites by decreasing the adsorption energy of H 2 O molecules onto the active sites, and thus, leading to an increase in the OER activity . DFT calculations have suggested that the existence of oxygen vacancies could decrease the hindrance of the adsorption of H 2 O/OH − at low‐coordination Co 3+ sites . The optimized ZnCo 2 O 4 /Co 3 O 4 /NC‐CNT‐700 sample also shows comparable activity for the OER among the as‐prepared catalysts, commercial IrO 2 , and a recently reported reference catalyst (Table S3 in the Supporting Information).…”

“…[22] The integration of oxygen vacancies, composition, and interface synergistic effects could promote the formation of CoOOH, but an understanding of the OER mechanism is challenging due to multiple-electron transfer in the OER. [54,57] In addition to catalytic activity,s tability is another important criteriont oc onsider for catalysts. Cyclic voltammetry and chronoamperometric tests were explored ( Figure 4C).…”

Defect‐Driven Enhancement of Electrochemical Oxygen Evolution on Fe–Co–Al Ternary Hydroxides

“…The faradaic resistance of Fe 3 Co 2 Al 2 ‐AE was 490 Ω at a working potential of 0.45 V, which is lower than those for both Fe 3 Co 2 and Fe 3 Co 2 Al 2 . The long‐term stability of Fe 3 Co 2 Al 2 ‐AE was assessed by chronoamperometric measurements in 1 m KOH solution (Figure S8), which showed the material to be stable or 5.5 h. Most notably, the OER mass activity of Fe 3 Co 2 Al 2 ‐AE was found to be 48 times that of Fe 3 Co 2 and 2.35 times that of Fe 3 Co 2 Al 2 at an overpotential of 350 mV (Table S2) …”