Cathodes for hydrogen evolution

Good surface coverage

Chlor Alkali (CA) and Alkaline Water Electrolysis (AWE) cathodes characteristics:
Cathode electrodes used in chlor-alkali electrolyzers are usually made of carbon steel in diaphragm cells and nickel in membrane cells.
AWE cells use a diaphragm as separator but with a configuration like CA membrane devices and cathodes are made in nickel or nickel - plated steel.
In this operations, the cathode overvoltage, influenced mainly by the electrode material and the operating current density, can heavily impact the overall the cell voltage and therefore the specific power consumption of the plant.

Enhanced catalytic sites

Increasing energy prices in recent years are a clear driving force in “hydrogen evolving” applications to develop materials such as mixed oxides catalytic coatings and high surface – high performing nickel-based electrodes as cathodes to reduce energy consumption.

Current chlor alkali membrane and alkaline water electrolysis cells cathodes are characterized by the following technical solutions:

• Improved electrode geometry able to reduce gas stagnation and preserve the membrane / diaphragm separator;
• Reduction of the average inter - electrodic distance – zero gap configuration;
• Implementation of an elastic cathode structure to guarantee a “full” zero gap in any operating condition;
• Increase of the contact points between the electrode and the current collector, decreasing the IR drop through a more homogeneous distribution of the electric current;
• Application of catalytic cathodic coating, capable of reducing the overvoltage of the hydrogen evolution reaction;