H2S nano-jetting through a p–n junction-like graphene/Au nano-injector: a molecular dynamics study

Abstract

This paper uses fully atomistic molecular dynamics to outline the dynamics of H2S nano-jetting through a p–n junction-like graphene/Au nano-injector. We examined the effects of nano-injector diameter (d), system temperature (T), and the extrusion velocity (v) of a graphite piston plate on the formation of H2S nano-jets, system pressure, and the number of molecules (N m) in the outflow. The combined effects of high critical pressure and small orifice resulted in a larger jet angle, which increased the number of H2S molecules stuck to the graphene surface at the outlet. Moving the graphite piston plate toward the orifice of the nano-injector increased in the change in momentum and interactive forces between H2S molecules, resulting in three phases of pressure establishment in the nano-injector: incubation (phase I), steep pressure increase (phase II), and high pressure (phase III). When operated at T ≥ 300 K and v < 27.912 m/s, the proposed nano-jet device is able to produce a well-dispersed spray of H2S without H2S molecules sticking to the graphene surface at the outlet. The p–n junction-like Au-doped graphene surface provides an additional energy barrier preventing the transport of electrons from H2S molecule to the graphene. This inhibits the accumulation of H2S molecules and subsequent blockages at the exit of the nano-injector. Simulation results demonstrate the potential of using chemiresistive sensing to monitor H2S flow patterns during nano-jetting. The findings presented in this study could be transformative to the design of nano-injectors for other gases commonly used as biomarkers.