Competitive Adsorption of H2O and SO2 on Catalytic Platinum Surfaces: a Density Functional Theory Study

ABSTRACT Platinum has been widely used as the catalyst of choice for production hydrogen in hybrid sulphur (HyS) cycle. In this cycle, water (H2O) and dioxide (SO2) react to form sulphuric acid hydrogen. However, surface reactivity platinum towards H2O SO2 is not yet fully understood, especially considering competitive adsorption that may occur on surface. study, we have carried out density functional theory calculations with long-range dispersion corrections [DFT-D3-(BJ)] investigate effect both Pt (001), (011) (111) surfaces. Comparing a single molecule various surfaces, it was found lowest energy (Eads = -1.758 eV) obtained dissociative (001) surface, followed by molecular -0.699 -0.464 eV). For adsorption, trend similar, -2.471 -2.390 -1.852 During SO2, will therefore preferentially adsorb onto If concentration increases, self-reaction between two neighbouring molecules occur, leading formation monoxide (SO) -trioxide (SO3) which could lead poisoning catalytic Keywords: Platinum, water, dioxide, hydrogen, theory.