CN-121976225-A - Surface modified iridium oxide catalyst and preparation method of stable suspension slurry thereof

CN121976225ACN 121976225 ACN121976225 ACN 121976225ACN-121976225-A

Abstract

The invention discloses a surface modified iridium oxide catalyst and a preparation method of stable suspension slurry thereof, belonging to the technical field of electrolyzed water. The preparation method of the surface modified iridium oxide catalyst comprises the following steps of reacting iridium oxide and nonafluorohexyl triethoxysilane in a solvent to generate the surface modified iridium oxide catalyst. The preparation method of the stable suspension type iridium oxide catalyst slurry comprises the following steps of mixing an ionomer or dispersion liquid thereof with a solvent and the surface modified iridium oxide catalyst to prepare a final slurry. According to the invention, the iridium oxide catalyst is subjected to surface modification by TES, so that the comprehensive performance of the catalyst slurry is obviously improved, and thus, the synergistic optimization in aspects of colloid stability, dispersion uniformity, interface characteristics, process applicability and the like is realized, and a reliable technical basis is provided for preparing a high-performance and uniform-structure catalytic layer.

Inventors

WU YU
JIANG LONG
LI QIANG
LIU WENHAO
SUN HAORAN
HUANG YUN
CHEN MING

Assignees

东方电气集团东方锅炉股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260209

Claims (10)

1. A preparation method of a surface modified iridium oxide catalyst is characterized in that iridium oxide and nonafluorohexyltriethoxysilane are reacted in a solvent to generate the surface modified iridium oxide catalyst.
2. The method for preparing the surface-modified iridium oxide catalyst according to claim 1, wherein the mass ratio of nonafluorohexyltriethoxysilane to iridium oxide is 0.01:1-0.6:1, preferably 0.4:1; The mass content of iridium oxide in the solvent is 0.01-20wt% so as to ensure that the reaction system has proper fluidity and sufficient reaction interface.
3. The method for preparing the surface-modified iridium oxide catalyst according to claim 1, wherein the solvent is a water-alcohol mixed solvent, the mass ratio of water to alcohol is 0.5:9.5-9.5:0.5, and the alcohol comprises at least one of methanol, ethanol, n-propanol, isopropanol, 1-butanol, 2-methyl-2-propanol, ethylene glycol and glycerol.
4. The method for preparing a surface-modified iridium oxide catalyst according to claim 1, wherein the reaction is carried out for 2-6 hours, preferably 3 hours, at room temperature.
5. The method for preparing the surface modified iridium oxide catalyst according to any one of claims 1 to 4, which is characterized in that iridium oxide is dispersed in a solvent to form a preliminary dispersion suspension, and a nonafluorohexyl triethoxysilane solution is dropwise added into the suspension to react, and solid-liquid separation is carried out to obtain the surface modified iridium oxide catalyst; preferably, the nonafluorohexyl triethoxysilane solution is prepared by dissolving nonafluorohexyl triethoxysilane in ethanol, and the concentration of the nonafluorohexyl triethoxysilane solution is 2-20wt%.
6. The method for preparing a surface-modified iridium oxide catalyst according to claim 1, wherein the iridium oxide is subjected to drying treatment before being fed; preferably, the method further comprises a post-treatment step, after the reaction is finished, solid-liquid separation is carried out, and the precipitate is washed and dried to obtain the surface modified iridium oxide catalyst.
7. A surface modified iridium oxide catalyst prepared by the method of any one of claims 1 to 6.
8. Use of the surface-modified iridium oxide catalyst according to claim 7 for the preparation of an iridium oxide catalyst slurry.
9. A process for preparing a stable suspension iridium oxide catalyst slurry comprising the steps of mixing an ionomer or dispersion thereof with a solvent, the surface modified iridium oxide catalyst of claim 7 to prepare a final slurry; preferably, the ionomer is a perfluorosulfonic acid resin Preferably, the ionomer dispersion comprises any one of Nafion D520 and Nafion D2020 of the Kemu; preferably, the solvent is a mixed solvent of an organic solvent and water, wherein the volume ratio of the organic solvent to the water is 0.5:9.5-9.5:0.5, and the organic solvent comprises at least one of monohydric alcohol, dihydric alcohol and polyhydric alcohol (2 < alcohol hydroxyl content < 10), ether of C1-C10 and N-methyl pyrrolidone of C1-C10; More preferably, the number of alcoholic hydroxyl groups in the polyol is greater than 2 and less than 10; Preferably, the mass ratio of the ionomer to the surface modified iridium oxide catalyst is 0.1:1-5:1; Preferably, the ionomer or dispersion thereof, the solvent and the surface modified iridium oxide catalyst are initially and uniformly mixed by a vortex oscillator, and then are subjected to ultrasonic dispersion in an ultrasonic cleaner, so that stable suspension type iridium oxide catalyst slurry is obtained.
10. A stable suspension iridium oxide catalyst slurry prepared by the method of claim 9.

Description

Surface modified iridium oxide catalyst and preparation method of stable suspension slurry thereof Technical Field The invention belongs to the field of electrolyzed water, and particularly relates to a surface modified iridium oxide catalyst and a preparation method of stable suspension slurry thereof. Background The development of hydrogen energy is a key strategic path for solving the large-scale absorption and long-term storage of renewable energy sources and realizing deep decarburization in high-carbon industries such as chemical industry, metallurgy and the like. Among various hydrogen production technologies, proton Exchange Membrane (PEM) water electrolysis hydrogen production technology is considered as one of the most promising advanced green hydrogen production technologies due to the fast response speed, high current density and excellent energy efficiency, and is particularly suitable for power generation coupling with renewable energy sources with volatility (such as wind power and photovoltaic). The market prospect is wide, the installed scale requirement of the Chinese electrolytic tank is expected to reach hundreds of gigawatts by 2030, wherein the PEM electrolytic technology has remarkable advantages in the aspect of consuming renewable energy and discarding electricity by virtue of the quick response and flexible regulation characteristics, and the market occupation ratio is expected to be continuously improved. The core reaction of PEM electrolyzed water occurs on both sides of the membrane electrode, with the anodic Oxygen Evolution Reaction (OER) being in an extremely harsh environment of strong acidity, high potential. Under the environment, iridium oxide (IrO 2) becomes an anode catalyst with the most industrial application prospect in PEM (electro-mechanical membrane) water electrolysis technology due to the excellent OER catalytic activity and long-term chemical stability. In the electrode preparation process, iridium oxide particles need to be suspended and dispersed in a solvent to form catalyst slurry, and a microstructure precise anode catalytic layer is formed through processes such as spraying, transfer printing and the like. The microstructure (e.g., particle distribution, porosity, etc.) of the catalytic layer directly determines the efficiency and durability of OER, while the suspension stability of iridium oxide slurries is a key factor in regulating the microstructure. Iridium oxide catalyst slurries typically consist of iridium oxide particles, perfluorinated sulfonic acid ionomers (e.g., nafion) and water/alcohol mixed solvents, which are a hydrotropic system. The suspension stability is affected by a number of factors including particle-ionomer-solvent triphasic interfacial tension, steric effects, solvation, and gravity settling. The prior art faces serious challenges in preparing high-stability iridium oxide catalyst slurry, and the method is as follows: (1) The extremely high particle density results in severe sedimentation, iridium oxide densities up to about 11.66 g/cm 3, far exceeding conventional catalyst support materials such as 5.17 g/cm3 for Fe 3O4, 4.23 g/cm3 for TiO 2, and rapid gravity sedimentation and particle aggregation in the slurry are extremely prone to occur, resulting in slurry non-uniformity and coating composition gradients. (2) The severe working conditions limit the use of dispersants, namely the strong acidity (pH approximately 2), high potential (> 1.5V vs. RHE) and oxidizing environment of the anode of the PEM electrolyzer, so that the polymer or ionic surfactant conventionally used for improving the dispersibility cannot be used, and is easy to degrade and pollute the membrane electrode, thereby causing performance attenuation. (3) The high temperature synthesis leads to hard agglomeration, namely, iridium oxide is subjected to high temperature calcination in the preparation process to obtain high crystallinity and activity, so that firm micron-sized hard agglomerates are extremely easy to form. These agglomerates are difficult to re-dissociate into nanoscale primary particles during conventional slurry formulation, not only reducing catalyst utilization, but also exacerbating slurry instability. Although the prior art improves by adjusting the ionomer to catalyst ratio (I/C), optimizing the solvent system, etc., the prior art is limited by the fundamental problems described above, and the prior art still cannot obtain high stability iridium oxide catalyst slurry meeting the requirements of mass production and long-term storage without introducing external dispersants. This bottleneck severely restricts the fabrication of high performance, uniform catalytic layers, thereby affecting the hydrogen production efficiency, lifetime and cost of PEM electrolysers, impeding the large-scale commercial application of this technology. Therefore, the stabilization method of the iridium oxide catalyst slurry has the characteristics of effectively in