title: Photocatalytic hydrogen evolution from glycerol and water over nickel-hybrid cadmium sulfide quantum dots under visible-light irradiation.
abstract: Natural photosynthesis offers the concept of storing sunlight in chemical form as hydrogen (H2), using biomass and water. Herein we describe a robust artificial photocatalyst, nickel-hybrid CdS quantum dots (Nih-CdS QDs) made in situ from nickel salts and CdS QDs stabilized by 3-mercaptopropionic acid, for visible-light-driven H2 evolution from glycerol and water. With visible light irradiation for 20 h, 403.2 μmol of H2 was obtained with a high H2 evolution rate of approximately 74.6 μmol h(-1)  mg(-1) and a high turnover number of 38 405 compared to MPA-CdS QDs (mercaptopropionic-acid-stabilized CdS quantum dots). Compared to CdTe QDs and CdSe QDs, the modified CdS QDs show the greatest affinity toward Ni(2+) ions and the highest activity for H2 evolution. X-ray photoelectron spectroscopy (XPS), inductively-coupled plasma atomic emission spectrometry (ICP-AES), and photophysical studies reveal the chemical nature of the Nih-CdS QDs. Electron paramagnetic resonance (EPR) and terephthalate fluorescence measurements clearly demonstrate water splitting to generate ⋅OH radicals. The detection of DMPO-H and DMPO-C radicals adduct in EPR also indicate that ⋅H radicals and ⋅C radicals are the active species in the catalytic cycle.
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences, The Chinese Academy of Sciences, Beijing, 100190 (PR China), Fax: (+86) 10-8254-3580.
authors.forename: Jiu-Ju
authors.initials: JJ
authors.lastname: Wang
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Li
authors.forename: Xu-Bing
authors.initials: XB
authors.lastname: Li
authors.forename: Xiang-Bing
authors.initials: XB
authors.lastname: Fan
authors.forename: Qing-Yuan
authors.initials: QY
authors.lastname: Meng
authors.forename: Shan
authors.initials: S
authors.lastname: Yu
authors.forename: Cheng-Bo
authors.initials: CB
authors.lastname: Li
authors.forename: Jia-Xin
authors.initials: JX
authors.lastname: Li
authors.forename: Chen-Ho
authors.initials: CH
authors.lastname: Tung
authors.forename: Li-Zhu
authors.initials: LZ
authors.lastname: Wu
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D002384:Catalysis; D005990:Glycerol / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D008027:Light; D009532:Nickel / Q000737:chemistry*; D055668:Photochemical Processes; D045663:Quantum Dots / Q000737:chemistry*; D059205:Renewable Energy; D013440:Sulfides / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide; D014867:Water; D009532:Nickel; D006859:Hydrogen; D005990:Glycerol
keywords: biomass; hydrogen production; photocatalysis; quantum dots; water splitting