Enriching surface oxygen vacancies of spinel Co₃O₄ to boost H₂O adsorption for HER in alkaline media

Abstract

Oxygen-defected Co3O2.64S0.33 (namely CoO0.88S0.11) particulate spheres (PS) were prepared via a solid-state sulfurization of spinel Co3O4 at 300 oC in Ar. The introduction of sulfur (S) atoms was found to...

Superimposed Effect of La Doping and Structural Engineering to Achieve Oxygen-Deficient TiNb2O7 for Ultrafast Li-Ion Storage

“…To determine the relative content of oxygen deficiencies, EPR tests were carried out. As demonstrated in Figure d, all samples display EPR signals at g = 2.002 (typical signal of oxygen vacancies), where La–M–TNO (0.03) shows the largest EPR signal than TNO and M–TNO because of La 3+ doping . Interestingly, TNO and M–TNO samples also showed obvious EPR signals, suggesting that TNO and M–TNO samples contain oxygen vacancy as well.…”

“…As demonstrated in Figure 3d, all samples display EPR signals at g = 2.002 (typical signal of oxygen vacancies), where La−M−TNO (0.03) shows the largest EPR signal than TNO and M−TNO because of La 3+ doping. 49 Interestingly, TNO and M−TNO samples also showed obvious EPR signals, suggesting that TNO and M− TNO samples contain oxygen vacancy as well. The oxygen vacancies in TNO may be caused by the organic molecules, which capture oxygen atoms in the crystal lattice during the hydrothermal process and eventually leave oxygen vacancies in the compound.…”

Temperature dependent fabrication of various rod and rhombohedral-shaped mesoporous Co3O4 crystals and their capability towards elimination of toxic Cr(vi) ions from the aquatic environment

“…80 Furthermore, we can predict that owing to more oxygen vacancies in 400 1C heated Co 3 O 4 , it is more viable for chemisorption and redox reaction on its surface. 81 3.2.2. FT-IR analysis.…”

“…via oxidation/reduction processes. 125 Herein, a large number of free electrons are produced from the oxygen vacancies present in the Co 3 O 4 lattice 81,109,126 and they can eventually reduce the chemisorbed Cr( vi ) ions into Cr( iii ). The acid–base equilibrium equation is presented in eqn (12) and the redox reactions in both acidic and basic media are presented in eqn (13) and (14), respectively:The existence of both Cr( iii ) and Cr( vi ) peaks in the post-catalytic XPS study completely supports the above predicted mechanistic pathway (see Section 3.3.7.3.).…”

Recent Advances in Co‐Based Electrocatalysts for Hydrogen Evolution Reaction

“…f) HER polarization curves of Co 3 O 4 , CoS 2 , CoO 0.88 S 0.11 , and Pt/C. Reproduced with permission [114]. Copyright 2020, The Royal Society of Chemistry.…”