Theoretical Insights into the Thermodynamics and Kinetics of Graphene Growth on Copper Surfaces

Abstract

To control graphene growth on copper surfaces, we must understand the underlying growth mechanisms. Unfortunately, most high-resolution experimental characterization methods are not applicable under typical growth conditions, which makes theoretical simulations especially important in graphene growth mechanism studies. In this Feature Article, recent theoretical efforts in understanding graphene growth on copper surfaces are summarized. First-principles calculations indicate that methane decomposition on copper surfaces is very difficult. In contrast, dissociative adsorption of H 2 is exothermic and H adatom can reach an equilibrium with gas-phase hydrogen quickly. Although thermodynamic analysis is useful in estimating the concentrations of different C x H y species on the surface, reliable steady-state concentrations can only be obtained after the full kinetic network is constructed by kinetic Monte Carlo simulations or other methods, since graphene growth is a nonequilibrium process. With thermodynamic and kinetic insights provided by firstprinciples calculations and simulations, a unified picture can be obtained to understand graphene growth on Cu surfaces.

Understanding High-Temperature Chemical Reactions on Metal Surfaces: A Case Study on Equilibrium Concentration and Diffusivity of CxHy on a Cu(111) Surface

“… 33 The concentration of H is less sensitive to temperature, and it becomes slightly lower at higher temperatures because the dissociative adsorption of H 2 is weakly exothermic. 34 As a result, H coverage is much higher than that of carbon-containing species in graphene growth.…”

Strategies for boosting the activity of single-atom catalysts for future energy applications

“…For supported catalysts, improving the interaction between the atomic metal and the support is a positive pathway for gaining SACs with a unique electronic structure, which may exhibit remarkable activity and stability at the same time. [125][126][127][128]132 Therefore, suitable supports with an expansive area, lowcoordination atoms, dense defects, interfaces, edges, and also strain effects will help optimize the activity, selectivity, and stability of the SACs. [133][134][135] In addition, novel properties such as quantum size effects, unsaturated coordination environments, and local electronic modulation between single atoms and substrates have received extensive attention in recent years.…”

Theoretical Study of Chemical Vapor Deposition Synthesis of Graphene and Beyond: Challenges and Perspectives

“…More importantly, CVD synthesis of 2D materials is generally a kinetic process under a nonequilibrium condition; strategies for predicting the concentrations of active species under such conditions are in high demand. 212 (ii) New methods of investigating the nucleation of 2D materials are required. Current theoretical studies on exploring the structures of possible nucleus precursors are based on empirical rules.…”

“…Understanding of the active species for the synthesis of graphene from other precursors or 2D materials with multicompositions is rare. More importantly, CVD synthesis of 2D materials is generally a kinetic process under a nonequilibrium condition; strategies for predicting the concentrations of active species under such conditions are in high demand …”