CN-122013244-A - Cobalt complex pre-catalyst for electrocatalytic oxygen evolution and preparation method thereof

Abstract

The invention discloses a cobalt complex pre-catalyst for electrocatalytic oxygen evolution and a preparation method thereof, and relates to the technical field of functional complexes. The cobalt complex pre-catalyst (CotPBA-anion) is composed of a cobalt cation unit chelated by tPBA and a catalyst which is obtained by coordinating with anions and is derived from CotPBA-anion through in-situ electrochemical reconstruction, and the structure of the catalyst is CoOOH/tPBA and is characterized by organic ligand loaded cobalt oxyhydroxide. Wherein CoOOH/tPBA reconstituted with CotPBA-Cl exhibits optimal electrochemical activity and stability. The preparation process of the pre-catalyst is simple, the reaction condition is mild, and the pre-catalyst shows good electrocatalytic oxygen evolution reaction activity and electrochemical stability after simple reconstruction.

Inventors

• ZHANG QIUYU
• ZHANG GENG
• GUO WEI
• LI XIANG
• WANG JINXIN

Assignees

• 西北工业大学

Dates

Publication Date

20260512

Application Date

20260104

Claims (10)

1. 1. The cobalt complex precatalyst for electrocatalytic oxygen evolution is characterized in that the structure of the cobalt complex precatalyst is composed of tPBA chelated cobalt complex cation units and anions; Wherein tPBA is tris ((1- (pyridin-4-methyl) -1H-benzo [ d ] imidazol-2-yl) methyl) amine, and the anion is chloride, formate or nitrate; the cobalt complex precatalyst is a triclinic system.
2. 2. The cobalt complex precatalyst for electrocatalytic oxygen evolution according to claim 1, wherein the cobalt complex precatalyst is converted into a metal organic hybrid catalyst by electrochemical activation.
3. 3. The cobalt complex precatalyst for electrocatalytic oxygen evolution according to claim 1, wherein the molecular formula of the cobalt complex precatalyst comprises [ Co (tPBA) Cl ] & Cl, [ Co (tPBA) FA ] & NA or [ Co (tPBA) NA ] & NA; wherein Cl is chloride ion, FA is formate ion, and NA is nitrate ion.
4. 4. A method for preparing the cobalt complex precatalyst for electrocatalytic oxygen evolution according to any one of claims 1-3, comprising the steps of: Dissolving cobalt salt and tPBA in an organic solution, uniformly mixing with deionized water, and sealing to obtain a mixed solution; reacting the mixed solution at 80-100 ℃ for 60-80 hours to obtain a reaction solution; And (3) collecting, washing, drying and grinding the reaction solution in sequence to obtain the cobalt complex precatalyst for electrocatalytic oxygen evolution.
5. 5. The method for preparing a cobalt complex precatalyst for electrocatalytic oxygen evolution according to claim 4, wherein the cobalt salt is cobalt chloride hexahydrate or cobalt nitrate hexahydrate; The molar ratio of the cobalt salt to tPBA is 1:0.5-1.5.
6. 6. The method for preparing a cobalt complex precatalyst for electrocatalytic oxygen evolution according to claim 4, wherein the organic solvent is N, N-dimethylacetamide or N, N-dimethylformamide; the volume ratio of the organic solvent to the deionized water is 1:1-10.
7. 7. Use of a cobalt complex precatalyst for electrocatalytic oxygen evolution according to any of claims 1-3 for the preparation of a metal organic hybrid catalyst.
8. 8. A metal organic hybrid catalyst is characterized in that the cobalt complex pre-catalyst is prepared by activating the cobalt complex pre-catalyst according to any one of claims 1-3 in 1M KOH for 30 minutes at a constant current density of 10 mA/cm 2 , and the metal organic hybrid catalyst has a tPBA-loaded cobalt oxyhydroxide structure.
9. 9. Use of a cobalt complex precatalyst for electrocatalytic oxygen evolution according to any one of claims 1-3.
10. 10. Use of the metal organic hybrid catalyst of claim 8 in electrocatalytic oxygen evolution.

Description

Cobalt complex pre-catalyst for electrocatalytic oxygen evolution and preparation method thereof Technical Field The invention relates to the technical field of functional complexes, in particular to a cobalt complex pre-catalyst for electrocatalytic oxygen evolution and a preparation method thereof. Background The intermittent electric energy is converted into hydrogen with high energy density (120 MJ kg –1) by the water electrolysis technology, which is beneficial to realizing sustainable energy. The efficiency of water electrolysis is mainly dependent on the Oxygen Evolution Reaction (OER), whose slow multi-step proton-coupled electron transfer process limits the energy conversion efficiency of the electrocatalytic device. Although noble metal materials such as ruthenium and iridium are widely used as OER reference catalysts, their high cost and scarcity make it difficult to realize large-scale industrial applications. In this direction, much effort has been devoted to developing rich-reserves transition metal catalysts to improve OER efficiency. Meanwhile, the organic ligand is used for regulating and controlling the electronic structure and coordination structure of the transition metal, improving OER dynamics and thermodynamic performance of the transition metal, and accordingly, positively regulating a catalytic reaction path and reducing energy barriers required by the reaction. Therefore, complexes constructed from organic ligands and transition metals are considered potential candidates. The complex undergoes dynamic reconstitution during OER, which alters the local electronic and stereochemical structure of its metal center, thereby promoting its electrochemical activity and kinetic properties. Thus, the complex is often used as a precatalyst for constructing high activity OER catalysts, and its complex reconstitution process results in complex structure difficult to achieve directional design. Some studies have shown that by designing the ligand structure and coordination, efficient reconstitution of the complex to a highly active catalyst is facilitated. In particular, complex precatalysts with weak metal-ligand interactions are constructed which can induce deep reconstitution of their coordination structures and framework structures during OER. In short, partial dissolution of the ligand from the surface of the complex pre-catalyst promotes efficient exposure of the metal sites and allows for asymmetric modulation of the electronic structure, resulting in efficient generation of the OER active phase. Therefore, the surface micro-environment change of the complex pre-catalyst in the reconstruction process is deeply and comprehensively recognized, and the forward conversion of the complex pre-catalyst to an active phase is favorably controlled. Disclosure of Invention Aiming at the defects in the background technology, the invention provides a cobalt complex pre-catalyst for electrocatalytic oxygen evolution and a preparation method thereof. The method uses an electrochemical process to convert the cobalt complex precatalyst into a metal organic hybrid catalyst useful for catalyzing OER reactions. The first object of the invention is to provide a cobalt complex pre-catalyst for electrocatalytic oxygen evolution, wherein the structure of the cobalt complex pre-catalyst is composed of tPBA chelated cobalt complex cation units and anions; Wherein tPBA is tris ((1- (pyridin-4-methyl) -1H-benzo [ d ] imidazol-2-yl) methyl) amine, and the anion is chloride, formate or nitrate; the cobalt complex precatalyst is a triclinic system. Preferably, the cobalt complex precatalyst is a metal organic hybrid catalyst converted by electrochemical activation. Preferably, the molecular formula of the cobalt complex precatalyst comprises [ Co (tPBA) Cl ]. Cl, [ Co (tPBA) FA ]. NA or [ Co (tPBA) NA ]. NA; wherein Cl is chloride ion, FA is formate ion, and NA is nitrate ion. The second object of the invention is to provide a method for preparing a cobalt complex precatalyst for electrocatalytic oxygen evolution, comprising the steps of: Dissolving cobalt salt and tPBA in an organic solution, uniformly mixing with deionized water, and sealing to obtain a mixed solution; reacting the mixed solution at 80-100 ℃ for 60-80 hours to obtain a reaction solution; And (3) collecting, washing, drying and grinding the reaction solution in sequence to obtain the cobalt complex precatalyst for electrocatalytic oxygen evolution. Preferably, the cobalt salt is cobalt chloride hexahydrate or cobalt nitrate hexahydrate; The molar ratio of the cobalt salt to tPBA is 1:0.5-1.5. Preferably, the organic solvent is N, N-dimethylacetamide or N, N-dimethylformamide; the volume ratio of the organic solvent to the deionized water is 1:1-10. The third object of the invention is to provide an application of the cobalt complex pre-catalyst for electrocatalytic oxygen evolution in preparing a metal organic hybrid catalyst. The fourth object of the