title: Ultrafast and Efficient Transport of Hot Plasmonic Electrons by Graphene for Pt Free, Highly Efficient Visible-Light Responsive Photocatalyst.
abstract: We report that reduced graphene-coated gold nanoparticles (r-GO-AuNPs) are excellent visible-light-responsive photocatalysts for the photoconversion of CO2 into formic acid (HCOOH). The wavelength-dependent quantum and chemical yields of HCOOH shows a significant contribution of plasmon-induced hot electrons for CO2 photoconversion. Furthermore, the presence and reduced state of the graphene layers are critical parameters for the efficient CO2 photoconversion because of the electron mobility of graphene. With an excellent selectivity toward HCOOH (>90%), the quantum yield of HCOOH using r-GO-AuNPs is 1.52%, superior to that of Pt-coated AuNPs (quantum yield: 1.14%). This indicates that r-GO is a viable alternative to platinum metal. The excellent colloidal stability and photocatalytic stability of r-GO-AuNPs enables CO2 photoconversion under more desirable reaction conditions. These results highlight the role of reduced graphene layers as highly efficient electron acceptors and transporters to facilitate the use of hot electrons for plasmonic photocatalysts. The femtosecond transient spectroscopic analysis also shows 8.7 times higher transport efficiency of hot plasmonic electrons in r-GO-AuNPs compared with AuNPs.
authors: KU-KIST Graduate School of Converging Science and Technology, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 136-701, South Korea.
authors: Dinesh
authors: D
authors: Kumar
authors: KU-KIST Graduate School of Converging Science and Technology, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 136-701, South Korea.
authors: Ahreum
authors: A
authors: Lee
authors: Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University , Busan 609-735 South Korea.
authors: Taegon
authors: T
authors: Lee
authors: Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University , Busan 609-735 South Korea.
authors: Manho
authors: M
authors: Lim
authors: KU-KIST Graduate School of Converging Science and Technology, Korea University , 145 Anam-ro, Seongbuk-gu, Seoul 136-701, South Korea.
authors: Dong-Kwon
authors: DK
authors: Lim
keywords: CO2 photoconversion; Plasmonic nanoparticles; hot electron; photochemical reaction; visible light irradiation