The necessity of structural irregularities for the chemical applications of graphene

Graphene is a fashionable material in the realm of nanotechnology, but its potentials are somehow misunderstood. Although a defect-free flat graphene looks perfect with exceptional mechanical properties, this perfectly ordered hexagonal structure is chemically less active, and not of practical interest in the applications involving chemical reactions. In most applications (e.g., in sensors, energy storage, electrochemical systems, catalysis, etc.) of graphene, the superior properties are usually because of the reactivity of intrinsic defects and dangling bonds. Unfortunately, the ordered structure of graphene mistakenly gets all the credits, and then, all attentions and even market supplies are shifted towards ideal graphene (i.e., chemically inert). There is a gradual shift to using graphene nanoribbons and quantum dots instead of ideal seamless graphene because the results are better. Understanding the roles of possible irregularities can pave the path for subtly designing graphene for the practical applications. Reducing the reactive sites may make graphene more well-defined structure-wise but practically less useful. While briefly describing common approaches for manipulating the classic structure of graphene, we summarize their successful utilization for various applications, e.g., in electrochemistry, luminescence, and catalysis. © 2017 Elsevier Ltd