Hydrogen adsorption on doped graphene investigated by a DFT-based tight-binding method.

DFTB is a tight binding model based on density functional theory (DFT); it is less exact than the latter, but much faster, and allows calculations for much larger ensembles and timescales. Here we explore its possibilities for electrochemistry, taking hydrogen adsorption on pristine and doped graphene as an example. The speed and the flexibility of DFTB enabled us to provide a broad panorama incorporating not only the effects of various dopants, but also of ionic adsorption and double-layer charging. With the exception of graphene doped with boron, our results agree well with literature data based on DFT where they exist, and with a few control DFT calculations performed by us. DFTB is well suited to perform molecular dynamics for the electrochemical interface. As an example, we have investigated the effect of water on hydrogen adsorption on pristine graphene.