Aiming at the problem that present gas sensors can only detect a single type of gas

an integrated multifunctional gas sensing element based the 2D-nano thinfilm material graphene is designed. The sensing element is divided into four parts and it can detect three different gas with a graphene film which is disposed by different steps. The key detection part of ammonia is oxide graphene. The key detection part of hydrogen is palladium doping graphene. The key detection part of carbon monoxide is aluminum doping graphene. These three gas sensitive module can be integrated on a single chip via the MEMS technology and the graphene film transfer technology and obtain a new integrated graphene gas sensing element.