How Does the Step on Graphite Surface Impact Ice Nucleation?

Abstract

Heterogeneous ice nucleation has always been a hot research topic because of its fundamental importance to a variety of research areas, from climate to biology and from aviation to the energy industry. The formation of ice in the earth’s atmosphere depends on aerosols of various sources. As the main component of atmospheric aerosols, carbon particles composed of graphite have attracted much attention in heterogeneous ice nucleation. There is great variability in the freezing efficiency of ice induced by surface nanostructures, and the presence of surface defects, such as steps, can lead to the complex behavior of ice nucleation. In this work, molecular dynamics (MD) simulation was employed to investigate ice nucleation on graphite surfaces with the step structure. It was found that the graphite step with a real atomic structure reduced the freezing efficiency of surfaces, which was attributed to the large interfacial free energy between ice and the side face of the graphite steps. It was demonstrated by further investigations that the effect of nanogrooves consisting of step edges on ice nucleation was not only determined by the matching of groove width and ice lattice constant but also by the atomic structure of nanogrooves, shedding light on the study of control strategy of ice nucleation by surface nanostructures.