CN-122029311-A - Electrocatalytic coating

Abstract

The invention discloses a process for plating an electrolytic tank polar plate, which comprises the steps of preprocessing the polar plate and plating nickel-cobalt alloy on the polar plate through electrodeposition. Nickel-cobalt alloy is electrodeposited from the eutectic solvent to form a nanocrystalline electrocatalytic coating having corrosion resistance.

Inventors

• Gita Srinivasan
• LUO QIXUAN
• W. A.M.B. Wang Abdullah Sani

Assignees

• 马来西亚国家石油公司

Dates

Publication Date

20260512

Application Date

20240723

Priority Date

20230724

Claims (10)

1. 1. The plating process of the electrolytic tank polar plate comprises the following steps: Pretreating polar plate, and Plating nickel-cobalt alloy on the polar plate by an electrodeposition method; the method is characterized in that the nickel-cobalt alloy is electrodeposited from a eutectic solvent to form a nanocrystalline electro-catalytic coating with corrosion resistance.
2. 2. The process according to claim 1, wherein the plate is preferably 316 stainless steel (SS 316).
3. 3. The process of claim 1, wherein pre-treating the plate comprises polishing, acid washing, dechroming, woods nickel impact plating, or any combination thereof.
4. 4. The process of claim 1, wherein the molar ratio of nickel to cobalt is in the range of 0.1:0.1 to 2:2.
5. 5. Process according to claim 1, wherein the molar ratio of nickel to cobalt is preferably 2:1.
6. 6. The process according to claim 1, wherein the eutectic solvent is a mixture of choline chloride, ethylene glycol, nickel chloride, and cobalt chloride.
7. 7. The process of claim 1 wherein a nickel-cobalt alloy is plated on the plate using a chronopotentiometric electrodeposition method with an applied current of 1mA/cm 2 to 3mA/cm 2 for a period of up to 20 minutes.
8. 8. The process according to claim 1, wherein the average grain size of the coating is less than 500nm.
9. 9. The plate made by the process of claim 1, comprising: plating of nickel-cobalt alloy; the method is characterized in that the nickel-cobalt alloy is electrodeposited from a eutectic solvent to form a nanocrystalline electro-catalytic coating with corrosion resistance.
10. 10. Use of the electrode plate according to claim 9 in alkaline water electrolysis and anion exchange membrane electrolysis.

Description

Electrocatalytic coating Technical Field The invention relates to an electrocatalytic coating of an electrolytic cell polar plate. Background Hydrogen is an ideal clean energy source compared to other energy sources because of its high heating value, high energy density and multiple storage modes. There are various ways of producing hydrogen. The method for preparing hydrogen by electrolyzing water has the advantages of high purity, simple operation, zero pollution and the like, and is a most commonly used method for converting renewable energy into hydrogen storage in market. However, currently, only less than 4% of the hydrogen production is based on the electrolysis process, and most of this is also hydrogen produced as a by-product of chlorine production. Thus, most of the hydrogen required depends on fossil fuel pathways for producing hydrogen by steam reforming of natural gas. This is due to the high electrical costs and associated legal regulations, which result in the production costs of the electrolysis process being higher than conventional fossil energy sources. In order to reduce CO 2 emissions and get rid of the reliance on fossil energy carriers, it is necessary to greatly increase the hydrogen share produced using renewable energy sources in the next decades. Thus, water electrolysis is a key technology for decomposing water into hydrogen and oxygen using renewable energy sources. After drying and removing oxygen impurities, the purity of the hydrogen is higher than 99.9 percent, and the hydrogen can be directly utilized. For water electrolysis, there are three common techniques, alkaline Water Electrolysis (AWE), proton exchange membrane (or Polymer Electrolyte Membrane) Electrolysis (PEMEL), and Solid Oxide Electrolysis (SOEL). While both low temperature technologies AWE and PEMEL have a high degree of technical maturity, the high temperature SOEL technology is still in the development stage. Thus, the investment cost and the lifetime determine whether the AWE or PEMEL can be used in a large scale, the most advantageous system design. Currently, the investment cost of AWE is lower than PEMEL. In addition, the service life of the alkaline water electrolyzer is longer and the annual maintenance cost is lower than that of PEMEL systems. The inadequacies of AWE are being overcome progressively with further advances in technology. Because precious metals are not required, the capital expenditure of AWE systems is low, but the corrosion challenges that affect durability and efficiency are faced. It is therefore an object of the present invention to improve the efficiency of Alkaline Water Electrolysis (AWE) by providing electrocatalytic coating of the electrolyzer plates. Disclosure of Invention One aspect of the present invention provides a plating process for an electrolytic cell plate, comprising the steps of: Pretreating the polar plate, and Plating a nickel-cobalt alloy on the plate by electrodeposition; wherein the nickel-cobalt alloy is electrodeposited from the eutectic solvent to form a nanocrystalline electrocatalytic coating having corrosion resistance. Advantageously, the pretreatment ensures that the plate is free of any impurities or foreign matter, thereby enabling the coating to adhere firmly to the surface of the substrate. Advantageously, the electrodeposition is carried out using a eutectic solvent (DES), a non-aqueous electrolyte is chosen because the evolution of gas at the anode/solution interface is negligible, high current efficiency is obtained, and the eutectic solvent is mild in nature and non-corrosive compared to aqueous acidic solutions. Preferably, the plate is 316 stainless steel (SS 316). In one embodiment, the pretreatment of the plate may be accomplished by sanding, acid washing, dechroming, woodnickel impact plating, or a combination thereof. In one embodiment, the molar ratio of nickel to cobalt is preferably in the range of 0.1:0.1 to 2:2. Preferably, the molar ratio of nickel to cobalt is 2:1. In one embodiment, the eutectic solvent is a mixture of choline chloride, ethylene glycol, nickel chloride, and cobalt chloride. In one embodiment, the nickel-cobalt alloy is plated on the plates using a chronopotentiometric electrodeposition method with an applied current of 1mA to 3mA for a duration of up to 20 minutes. In one embodiment, the average grain size of the coating is less than 500nm. Advantageously, the Ni-Co alloy plated SS316 exhibits better durability in alkaline water electrolysis than bare SS316 (no Ni-Co alloy plating), and the plated SS316 surface has no significant catalyst layer spalling. Advantageously, the process provides a viable solution for depositing smooth nanocrystalline Ni-Co alloy coatings on SS316 by chronopotentiometric electrodeposition at ambient conditions using eutectic solvents. Another aspect of the present invention provides a plate comprising: Nickel-cobalt alloy plating; Wherein the nickel-cobalt alloy is electrodeposited fr