Oxygen Vacancy Engineering of Co₃O₄ Nanocrystals through Coupling with Metal Support for Water Oxidation

Abstract

Oxygen vacancies can help to capture oxygen-containing species and act as active centers for oxygen evolution reaction (OER). Unfortunately, effective methods for generating a high amount of oxygen vacancies on the surface of various nanocatalysts are rather limited. Here, we described an effective way to generate oxygen-vacancy-rich surface of transition metal oxides, exemplified with Co O , simply by constructing highly coupled interface of ultrafine Co O nanocrystals and metallic Ti. Impressively, the amounts of oxygen vacancy on the surface of Co O /Ti surpassed the reported values of the Co O modified even under highly critical conditions. The Co O /Ti electrode could provide a current density of 23 mA cm at an OER overpotential of 570 mV, low Tafel slope, and excellent durability in neutral medium. Because of the formation of a large amount of oxygen vacancies as the active centers for OER on the surface, the TOF value of the Co O @Ti electrode was optimized to be 3238 h at an OER overpotential of 570 mV, which is 380 times that of the state-of-the-art non-noble nanocatalysts in the literature.

Engineering the Interfaces of Superadsorbing Graphene‐Based Electrodes with Gas and Electrolyte to Boost Gas Evolution and Activation Reactions

“…We initially tested the electrocatalytic performance of the Gr‐based electrode for gas evolution processes, involving the in situ formation of hydrogen or oxygen gas bubbles at the interface of electrolyte and the catalyst. Obviously, stabilizing the catalyst‐liquid interface of the electrode and electrolyte (Figure a, b) without the formation of additional gas layers (Figure c, d) is of key importance to keep the active sites exposed to the electrolyte and thus maintain the current output of the electrode . Owing to the superadsorbance of graphene, it adsorbs both polar and nonpolar molecules in large quantities.…”

Nanoclay-modulated oxygen vacancies of metal oxide

“…In catalytic systems, intrinsic structural defects can distinctly enhance the catalytic activity of nanocrystals [7][8][9] . Motivated by the advantages for oxygen vacancies, many researchers have focused on the development of new methods and approaches to generate appropriate density of defects on nanocrystals [10][11][12] . Owing to its low-cost, outstanding redox capability and favorable electrical conductivity, Co 3 O 4 represents a promising candidate in various fields, including water splitting 13 , lithium-ion battery 14 , and particularly the field of heterogeneous catalysis 15,16 .…”

3D Metallic Ti@Ni0.85Se with Triple Hierarchy as High‐Efficiency Electrocatalyst for Overall Water Splitting

“…The XPS and Raman analysis demonstrated that NiOOH (Ni 3+ ) was formed during the OER. In addition, the CV of the Ti@Ni 0.85 Se‐THA electrode (Figure S11 in the Supporting Information) proved that the Ni 2+ /Ni 3+ pairs act as an active species for the oxidation of water molecules …”