Computational Investigation of Methane Sensing by Graphene: Influence of Temperature, Structural Defects, and Substitutional Doping

• RDF and SPE variations are used with MD simulations to study methane sensing. • Thermal conductivity of graphene is explored for sensing using the VDOS method. • Nitrogen doping and defects (vacancy, Stone-Wales) enhance methane adsorption. • Temperature effects on adsorption are analyzed using RDF and SPE variations. Methane is a highly flammable gas; minor leaks may create serious fire hazards and explosions. Early detection of methane leaks is crucial in homes, industries, and automobiles that use natural gas as fuel. This study focuses on the adsorption characteristics of graphene to detect the presence of methane using molecular dynamic simulations. This work also explores how different factors like temperature, structural defects, and substitutional doping affect how well graphene can adsorb, which then impacts its sensing ability. This study used parameters such as thermal conductivity, radial distribution function (RDF), and surface potential energy (SPE) to quantify methane sensing. Deposition of 25 methane molecules around 5nm x 5nm graphene results in an enhancement of thermal conductivity of approximately 140 W/mK. The RDF peaks directly indicate the maximum methane density and the most probable radial distance from the graphene. A decline in temperature by 10K can raise the RDF peak by about 2% and adding structural defects like Stone-Wales and vacancies can boost the RDF peak by about 25% when methane molecules are deposited at 300K. SPE decreases as methane molecules (adsorbates) attach to the graphene surface. Deposition of 25 molecules contributes to a 15 kcal/mol SPE reduction. This research also indicates that we can improve the sensing efficiency of graphene by changing the number of structural defects and doping levels. 1% nitrogen doping can contribute to approximately 10% enhancement in the RDF peak, which is useful for creating effective sensors that can detect small methane leaks.