Gas sensing performance of biomass carbon materials promoted by nitrogen doping and p-n junction

In order to realize the resource utilization of waste orange peel, N-doped porous carbon derived from orange peel (NCOP) was prepared by simple carbonization and first used in the field of gas sensors. Compared with the reduced graphene oxide (RGO) and multi walled carbon nanotubes (MWCNTs), the responses of NCOP to five analytes were improved by 3.32 ∼ 66.72 times and the effect of N doping on the gas sensitivity of NCOP was analyzed by First-principles calculations. Furthermore, the NCOP/RGO composite with p-n junctions was prepared to improve the gas sensing properties. The theoretical limit of detection of NCOP and NCOP/RGO composites to formaldehyde vapor was determined to be 16.7 and 7.7 ppb, respectively. The response time and recovery time of NCOP and NCOP/RGO to all five analytes were no more than 15.9, 5.4 s and 14.4, 5.0 s, respectively. More importantly, the sensor array based on RGO, MWCNTs, NCOP and NCOP/RGO can discriminatively and quickly detect multiple analytes at room temperature. The study showed that both self-doping and heterojunction can effectively improve the gas sensitivity of biomass carbon materials, which provided a useful reference for the resource utilization of biomass waste and the development of gas sensors.