title: Graphene-catalyzed photoreduction of dye molecules revealed by graphene enhanced Raman spectroscopy.
abstract: The unique electrical and optical properties of graphene have enabled its application in various photocatalysis reactions. However, graphene needs to be combined with photosensitizing co-catalysts such as TiO2 due to its negligible visible light absorption. Here, we report that the single layer graphene by itself is capable of catalyzing the photoreduction of dye molecules, which has been revealed by graphene-enhanced Raman spectroscopy studies. The proposed mechanism involves the electron transfer from graphene to temporarily empty HOMO states of photoexcited dye molecules, which can be interpreted as ultrafast hole transfer from dyes to graphene. We also confirm that graphene-encapsulated nitrobenzene dyes show less photoreduction, implying that the ambient hydrogen molecules are the important source of photoreduction into aniline dyes. The photocatalytic reactivity of graphene would find numerous energy and environmental applications in the future.
authors.affiliation: Department of Chemistry, College of Natural Sciences Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 08826, Republic of Korea. byunghee@snu.ac.kr dong98@snu.ac.kr.
authors.forename: Bora
authors.initials: B
authors.lastname: Lee
authors.affiliation: Department of Chemistry, College of Natural Sciences Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 08826, Republic of Korea. byunghee@snu.ac.kr dong98@snu.ac.kr.
authors.forename: Jin Hyoun
authors.initials: JH
authors.lastname: Kang
authors.affiliation: Department of Chemistry, College of Natural Sciences Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 08826, Republic of Korea. byunghee@snu.ac.kr dong98@snu.ac.kr.
authors.forename: Insu
authors.initials: I
authors.lastname: Jo
authors.affiliation: Department of Chemistry, College of Natural Sciences Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 08826, Republic of Korea. byunghee@snu.ac.kr dong98@snu.ac.kr.
authors.forename: Dongha
authors.initials: D
authors.lastname: Shin
authors.affiliation: Department of Chemistry, College of Natural Sciences Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 08826, Republic of Korea. byunghee@snu.ac.kr dong98@snu.ac.kr.
authors.forename: Byung Hee
authors.initials: BH
authors.lastname: Hong