Hydrogen sensors based on noble metal doped metal-oxide semiconductor: A review

With the exhaustion of traditional energy, increasing attention has been paid on the new energy resources like H2. Because of its inflammable and explosive properties, it is imperative and challenging to detect ppm-level H2 during the transport and use process. This paper firstly introduces the working principles and sensing mechanism of the hydrogen sensors based on noble metal doped metal-oxide semiconductors. Then, this paper focuses on the advancement of noble metal doped metal oxide hydrogen sensors, especially the room temperature hydrogen sensors, in the recent years. At the end, we propose that fabricating semiconductors with special morphologies, using two different noble metals for bimetallic doping or composite semiconductors with 2D nanomaterials like graphene/MoS2 to improve the room temperature sensing properties towards low H2 concentration should be the emphasis for the future work.