Chairlike and Boatlike Graphane: Active Photocatalytic Water Splitting Solar-to-Hydrogen Energy Conversion under UV Irradiation

摘要

Graphene sheets are zero gap semiconductors with exceptional properties. The zero gap of graphene renders the construction of graphene-based photocatalysts very difficult. To enhance and/or modify these properties, hydrogenated graphene, which is called graphane, is proposed. This in turn enhances graphene with significantly promoted charge migration, up-shifted conduction band (CB) level, enhances the potential the of CB, increases the band gap that favors the enhancement of the photocatalytic performance. Here, we investigated the suitability of two configurations of graphane, namely, chairlike and boatlike graphane to be used as active photocatalysts under ultraviolet (UV) irradiation. The optical absorption level exhibited an obvious enhancement in the UV region. The absorption edge of chairlike (boatlike) graphane is located at lambda = 364.6.1 (lambda = 334.1) nm, and the corresponding optical band gap is about 3.4 eV (3.71) eV, which well-matched with the UV region and the sufficient negative CB potential for H+/H-2 reduction. On the basis of these results, one can conclude that chairlike and boatlike graphane could satisfy all requirements to be an efficient photocatalyst.