Raney Nickel – Normal Catalyst for Alkaline Hydrogen Production Electrolyzers

The most commonly used normal catalyst in alkaline hydrogen production electrolyzer is Raney Nickel. Today, we would like to briefly introduce the origin, production, and processing of Raney Nickel.

Black Raney Nickel powder placed on white tabletop
Origin of Raney Nickel
  • In 1897, French chemist Paul Sabatier discovered that nickel in trace (a very small amount, meaning the amount of a substance in less than one part per million) could catalyze the hydrogenation of organic substances. Subsequently, nickel was used in the hydrogenation of many organic substances.
  • Since the 1920s, American engineer Murray Raney had worked to find a better catalyst for hydrogenation.
  • In 1924, Raney used a mixture of nickel/silicon with a ratio of 1:1, which was treated with sodium hydroxide, and silicon and sodium hydroxide reacted away to form a porous structure.
  • Raney found that this catalyst is 5 times more catalytically active than ordinary nickel for hydrogenation of cottonseed oil.
  • Rainey then used an alloy of nickel/aluminum with a ratio of 1:1 to make the catalyst and found that the resulting catalyst was even more active and obtained a patent in 1926.
  • Now, the ratio of 1:1 remains the preferred alloy ratio for Raney Nickel production.
Raney Nickel Partial Physicochemical Properties Specification Table
Appearance & Properties Silver-white hard metal
Main Ingredients Pure nickel
pH 7
Melting Point (°C) 1453
Boiling Point (°C) 2732
Molecular Formula Ni
Molecular Weight 58.70
Heat of Combustion (kJ/mol) Not available
Relative Density (Water = 1) 8.90
Relative Vapor Density (Air = 1) Not available
Saturated Vapor Pressure (kPa) 0.13 (1810 °C)
Production of Raney Nickel

Commercially, the nickel-aluminum alloy required for the production of Raney Nickel is a melt obtained by melting catalytically active metal nickel and aluminum in a furnace. Then quench and cool the melt. After that, pulverize the melt and finally it becomes uniform fine particles of Raney Nickel.

Process Introduction of Attaching Raney Nickel to Electrode Mesh

To attach Raney Nickel to the electrode mesh, the following methods are commonly used: thermal spraying, plasma spraying, and roll coating & calcination.

  • Thermal Spraying

    Thermal spraying is a surface finishing process in which the material is heated to molten by a high-temperature heat source (electric arc, plasma spraying, combustion flame, etc.), and the semi-molten state of the material is atomized by a high-speed airflow and sprayed on the surface of the purified and roughened parts to form a surface finish called a spray coating layer.

    Spraying alloy particles accelerated by heat, in the process of impact on the surface of the substrate to form a coating layer, the molten state or high plastic shape of the powder particles, with a certain flight speed impact on the substrate and interact with the substrate. It is an important stage in the formation of the coating layer.

    The approximate process is generally: spray pretreatment (cleaning, roughening, de-stressing, etc.) → spray primer (some do not need) → spray coating layer.

  • Plasma Spraying

    DC-driven plasma arc is used as a heat source to heat the material to a molten or semi-molten state, and spray at high speed to the surface of the pre-treated workpiece to form a firmly attached surface coating layer, which is also a kind of thermal spraying in principle.

    The approximate process is generally: pre-treatment of the workpiece → select the appropriate plasma → adjust the arc power → supply powder → adjust the spraying distance and spraying angle → adjust the relative movement speed of the spray gun and the workpiece → controlling the substrate temperature.

  • Roll Coating & Calcination

    Nickel-based alloy coatings are applied to the electrode material to form an alloy coating of uniform thickness, and the coating is subsequently obtained by calcination under an inert gas (to avoid oxidation) environment.

3 rectangular woven mesh samples are placed in different positions.

Nickel woven mesh after Raney Nickel spraying can improve surface adsorption and hydrogen production efficiency and is now favored by the majority of clients. If you want to know more about the relevant content, you can contact us .