Construction of Mobius-strip-like graphene for highly efficient charge transfer and high active hydrogen evolution

Charge transfer between the two surfaces of graphene is limited due to the anisotropy of graphene structure. To overcome this anisotropy of graphene in charge transfer, construction of an equivalent Mobius strip by iodination can provide a feasible approach to altering the charge transfer route by fabricating a coplanar structure. In this work, the conductivity, carrier concentration, mobility, and charge transfer efficiency of a Mobius-strip-like iodination graphene (MSIG) are significantly improved owing to the coplanar character of the topology, which is stitched by chainlike connected polyiodides I-3(-) and I-5(-)) over the edge of graphene. Such a Mobius-strip-like route offered easier electron tunneling between two graphene surfaces by strong Rashba spin-orbit coupling and flip-flop electron tunneling, and this flip-flop electron tunneling bridged the easier transfer route between far-located carbon atoms at the edges of graphene through the p orbitals in polyiodides. As a result, the electron transfer between the two graphene surfaces was enhanced. Activity results indicated that the photocatalyst MSIG/Pt based on such Mobius strip graphene exhibited better hydrogen evolution activity than un-iodide-doped graphene. The highest quantum efficiency, 35.6%, was achieved at 430 nm when Eosin Y was used as a photosensitizes. This enhancement could be attributed to lower energy consumption during electron transfer in MSIG from excited Eosin Y to the Pt co-catalyst because of reduced recombination of photogenerated carriers and prolonged lifetimes of photogenerated electrons. (C) 2017 Elsevier Inc. All rights reserved.