Semiconductor Metal Oxides for Hydrogen Gas Sensing: Optimum Sensitivity, Response Time and Premature Alert of Flammable Gases

The only practical way to imitate human nose function is via gas sensors which monitor air quality and provide a mean to premature alert of potential risk. A gas sensor can form a part of an early warning system, notifying the appropriate authorities or provide the feedback signal to a process control system. To achieve this, the gas sensor must be accurate and stable in-situ real time measurements. It is foreseen that hydrogen energy will form the infrastructure that will power future societies since it is a clean, cost-effective and renewable source of energy. However, hydrogen, being flammable gas, has a lower expolsion limit of 4% in air meaning that even a small spark can ignite the mixture. Therefore, hydrogen generation, transport and storage can be dangerous if not handled with caution. This requires high precision sensitive gas sensors which are able to detect the smallest leaks fastly. Semiconductor Metal Oxide gas sensors are an important candidate for this task.