title: Highly Enhanced Photoelectrochemical Water Oxidation Efficiency Based on Triadic Quantum Dot/Layered Double Hydroxide/BiVO4 Photoanodes.
abstract: The water oxidation half-reaction is considered to be a bottleneck for achieving highly efficient solar-driven water splitting due to its multiproton-coupled four-electron process and sluggish kinetics. Herein, a triadic photoanode consisting of dual-sized CdTe quantum dots (QDs), Co-based layered double hydroxide (LDH) nanosheets, and BiVO4 particles, that is, QD@LDH@BiVO4, was designed. Two sets of consecutive Type-II band alignments were constructed to improve photogenerated electron-hole separation in the triadic structure. The efficient charge separation resulted in a 2-fold enhancement of the photocurrent of the QD@LDH@BiVO4 photoanode. A significantly enhanced oxidation efficiency reaching above 90% in the low bias region (i.e., E < 0.8 V vs RHE) could be critical in determining the overall performance of a complete photoelectrochemical cell. The faradaic efficiency for water oxidation was almost 90%. The conduction band energy of QDs is ∼1.0 V more negative than that of LDH, favorable for the electron injection to LDH and enabling a more efficient hole separation. The enhanced photon-to-current conversion efficiency and improved water oxidation efficiency of the triadic structure may result from the non-negligible contribution of hot electrons or holes generated in QDs. Such a band-matching and multidimensional triadic architecture could be a promising strategy for achieving high-efficiency photoanodes by sufficiently utilizing and maximizing the functionalities of QDs.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology , Beijing 100029, People's Republic of China.|Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University , Beijing 100875, People's Republic of China.
authors.forename: Yanqun
authors.initials: Y
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology , Beijing 100029, People's Republic of China.
authors.forename: Ruirui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Chemistry and Nanoscience Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
authors.forename: Ye
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology , Beijing 100029, People's Republic of China.|Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University , Beijing 100875, People's Republic of China.
authors.forename: Dongpeng
authors.initials: D
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology , Beijing 100029, People's Republic of China.
authors.forename: Xu
authors.initials: X
authors.lastname: Xiang
keywords: layered double hydroxides; photoanodes; photoelectrochemistry; quantum dots; water oxidation