Advancement in the gas sensors based on chemically converted graphenes

Graphene based materials are believed to have great potential for developing gas sensors owing to its unique band structure, large specific surface area, high carrier mobility and so on. Prof. Gaoquan Shi and his group developed chemoresistor-type NO2 sensors based on chemically modified graphene materials (CMG) including sulfonated reduced graphene oxide (S-G) or ethylenediamine-modified reduced graphene oxide  (EDA-G).The weak combination of NO2molecules and the lone-pair electrons in functional groups make the sensor reversible. These sensors show 4.3 to 16.4 times stronger response toward NO2 gas than those of the reduced graphene oxide (rGO) counterpart. Furthermore, the CMG based sensors can spontaneously recover to their initial states by flowing N2 gas, without UV/IR light illumination or thermal assistance. The responses of the sensors also showed good linear relationships in a wide range of NO2 concentrations with low limits of detection.The easy fabrication of these CMG-based sensors makes them attractive for ultrasensitive detection of NO2 gas. This work also indicates that chemical modification is an effective approach for improving the performance of rGO in gas-sensing applications.

The result was published on Advanced Materials 2013, 25, 766-771.