Hydrogenation Dynamics of Biphenylene Carbon (Graphenylene) Membranes
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Hydrogenation Dynamics of Biphenylene Carbon (Graphenylene) Membranes Vinicius Splugues1, Pedro Alves da Silva Autreto1,2, Douglas S. Galvao1 1 Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, Campinas - SP, 13083-970, Brazil 2 Universidade Federal do ABC, Santo André-SP, 09210-580, Brazil ABSTRACT The advent of graphene created a revolution in materials science. Because of this there is a renewed interest in other carbon-based structures. Graphene is the ultimate (just one atom thick) membrane. It has been proposed that graphene can work as impermeable membrane to standard gases, such argon and helium. Graphene-like porous membranes, but presenting larger porosity and potential selectivity would have many technological applications. Biphenylene carbon (BPC), sometimes called graphenylene, is one of these structures. BPC is a porous twodimensional (planar) allotrope carbon, with its pores resembling typical sieve cavities and/or some kind of zeolites. In this work, we have investigated the hydrogenation dynamics of BPC membranes under different conditions (hydrogenation plasma density, temperature, etc.). We have carried out an extensive study through fully atomistic molecular dynamics (MD) simulations using the reactive force field ReaxFF, as implemented in the well-known Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code. Our results show that the BPC hydrogenation processes exhibit very complex patterns and the formation of correlated domains (hydrogenated islands) observed in the case of graphene hydrogenation was also observed here. MD results also show that under hydrogenation BPC structure undergoes a change in its topology, the pores undergoing structural transformations and extensive hydrogenation can produce significant structural damages, with the formation of large defective areas and large structural holes, leading to structural collapse.
INTRODUCTION Topologically, graphene can be considered as a two-dimensional, one-atom thick membrane formed by an array of hexagonal sp2 bonded carbon atoms (Figure 1A) [1-4]. It has been theoretically investigated since late 1940s as a model to describe some properties of graphite. After Novoselov and Geim, using a “scotch tape” method, experimentally obtained a single layer of graphene from highly oriented pyrolytic graphite (HOPG) [4], an extraordinary number of theoretical and experimental works has been published on this material. Although graphene presents several remarkable properties, there are some difficulties to be overcome before real graphene-based nanoelectronics can become a reality. These difficulties are mainly related to its zero bandgap band structure (semi-metal), which precludes its direct use for some devices, such as digital transistors and diodes [5]. Among the many possible applications of graphene [6,7], it has been proposed its use as a selective membrane for water filtration or some gases. However, graphene in its defectless form (pristine) has been shown to be impermeable even to the smallest spec
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