What are the Best Technologies for Measuring Oxygen in Hydrogen Environments?


Why is measuring Oxygen in Hydrogen required?

Measuring oxygen in hydrogen environments poses unique challenges. Hydrogen, when combined with even small amounts of oxygen, is highly flammable and can be explosive. With air containing oxygen, any hydrogen process will require precise measurements to ensure safety.

Several technologies have been developed over the years, each with its own set of advantages and limitations. In this blog, we will delve into the most prominent methods available, helping you understand which might be best suited for your specific application.

An Overview of Oxygen Sensor Technologies and their suitability for measurement in Hydrogen

Electrochemical Sensors

Originating in the mid-20th century and based on principles laid out by Walter Nernst in 1897, electrochemical sensors have been a reliable method for measuring oxygen levels from parts per billion (ppb) to 100% concentrations.

Electrochemical sensors are fundamentally consumable fuel cells and have the benefits of compact size, high accuracy, and minimal influence from other gases.

Advantages Disadvantages
Small form factor Consumable sensor
Accurate measurementTemperature sensitive
Minimal background gas influence
Suitability for Hydrogen Applications

For percent measurements, standard electrochemical cells can be used, but for ppm measurements, we recommend Hydrogen sensor designs to ensure the best measurement response.

For more information on PST product solutions, click here:

Intrinsically Safe Compact Oxygen Transmitter

Process Oxygen Analyzer for Hazardous Areas

Oxygen Analyzers for Petrochemical

Portable O2 Analyzers for Gas Purity Monitoring


The zirconia measurement technology enables highly sensitive and accurate oxygen concentration measurement with a fast measurement response. To achieve this, the sensors are heated to a high temperature. Different construction techniques of the zirconia sensor determine the heating requirement of the sensor. Due to this heating and the relatively low ignition temperature, hydrogen zirconia technology is NOT suitable for use with any combustible gases including hydrogen.

Suitability for Hydrogen Applications

NOT suitable for the measurement of Oxygen in ANY combustible gas, including hydrogen.


Using the known paramagnetic properties of oxygen, the thermo-paramagnetic sensor measurement technique offers a rugged sensing solution for percent measurement applications. Suitable for safe and hazardous area applications such as refineries and petrochemical plants.

Advantages Disadvantages
Rugged measurement technology Requires calibration to be performed in the gas composition to be measured.
Accurate, stable, and repeatable performanceSlower measurement response time
Long verification interval periods possible
Long sensor life
Suitability for Hydrogen Applications

Suitable for measurement of Oxygen in Hydrogen.

A note on Hydrogen Electrolysis. Hydrogen electrolysis requires many safety measurements including oxygen in hydrogen. However, if safety measurements are required during the start-up process where a purge gas, such as nitrogen, is being used to inert the electrolyzer, a thermo-paramagnetic sensor will not give an oxygen reading until the background gas is predominantly hydrogen, which may make this technology less suitable.

For more information on PST product solutions, click here: Oxygen Analyzer - Michell XTP601


The original founding work on the paramagnetism of gases was done by Pierre Curie in the late 19th century. The first commercial paramagnetic oxygen analyzers were introduced in the 1950’s, and as technology has evolved, the measurement technology has evolved since then. Today, the measurement technology can be used over the full range of 0-100% Oxygen and is credited with being an accurate, repeatable high-performance measurement technology.

Advantages Disadvantages
Minimal background gas influence Requires clean, dry gas sample
Fast measurement response time % measurement range only
Non-depleting measurement technology Requires periodic verification
Accurate and reliable measurement
Suitability for Hydrogen Applications

A measurement technology that enables good measurement performance for oxygen in hydrogen measurements when the gas composition changes during purging. Due to this lack of interference from changing gas compositions paramagnetic oxygen sensor technologies like our XPM601 are ideal for safety measurements in hydrogen electrolysis.

For more information on PST product solutions, click here: Paramagnetic Oxygen Analyzer – Michell XPM601

In Conclusion

In this guide we have focused on some of the core technologies for oxygen measurement and their suitability for measurement in the presence of hydrogen. Other technologies do exist, including optical fluorescence, infrared (IR), and tunable diode lasers (TDL). As the landscape of oxygen measurement technologies continues to evolve, staying informed about the latest advancements and understanding how they compare to existing solutions is essential. Each technology comes with its own set of advantages and disadvantages, making the selection process critical based on the specific needs of your application. Safety, accuracy, and reliability should be the key factors in determining the most appropriate oxygen measurement method for your hydrogen environment.

For further information on oxygen measurement technologies or to discuss which technology might be best suited for your specific needs, please don't hesitate to contact us

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