Controlling Water Oxidation Catalysis through Interlayer Arrangements and Vacancies toward Producing Clean Hydrogen

Hydrogenfuel is one of the most promising, renewable, and carbon-freealternatives to contaminating fossil fuels that are being used todate. Producing hydrogen by water splitting may not be efficient insome catalysts mainly due to the high overpotential that exists informing oxygen, a half-reaction that occurs on the anode where watermolecules are being oxidized. One of the best catalysts for the oxygenevolution reaction (OER) with a low overpotential is a unique two-dimensionalbilayer system composed of monolayers of defected graphene and Fe-doped & beta;-Ni(OH)(2). Here, we display by density functionaltheory how carbon vacancies and possible mechanical changes includingsliding and twisting between layers of graphene//& beta;-NiOOH affectthe OER overpotential. Our results show that larger sliding energybetween layers at an optimal concentration of carbon vacancies indicatesbetter adhesion and electron transfer between the layers that consequentlylowers the OER overpotential. This study contributes to understandingthat finding improved two-dimensional catalysts for green hydrogenproduction could be achieved by designing interfaces with greaterbonding and that sliding energy between the layers may serve as acontrol handle for engineering better catalysts.