  This work reports the modeling and simulation of gas sensors made from
pristine graphene nanoplatelets (P-GnPs) using COMSOL Multiphysics software.
The mass balance equation was solved while including contributions of
electromigration flux. An example GnP-based gas sensor was simulated to undergo
exposure to NO2 and CO gases at different concentrations to understand the
effects of adsorption. Various electrical properties and the overall sensor
responses were also studied as a function of gas concentration in order to
determine how viable such sensors could be for target gases. The results herein
show that the resistance of the P-GnP-based gas sensor decreases when exposed
to NO2 gas whereas an opposite trend is seen when CO gas is used for exposures,
ultimately suggesting that the P-GnPs exhibit p-type behavior. Sensitivities of
23 % and 60 % were achieved when the P-GnP-based gas sensor was exposed to 10
mol/m3 concentration of NO2 and CO at room temperature, respectively. The data
heavily suggest that a higher sensitivity towards CO may be observed in future
sensors. These simulations will benefit research efforts by providing a method
for predicting the behavior of GnP-based gas sensors.
