Ethanol photoreactions over Au–Pd/TiO2
Tóm tắt
A prototype Au–Pd/TiO2 catalyst was prepared, characterized and tested for the photoreaction of ethanol. XPS Au4f and Pd3d indicated that the as-prepared material is composed of metallic Au, metallic Pd as well oxidized Pd (Pd2+). Ar ion sputtering (5 min) of the catalyst surface resulted in almost total reduction of Pd2+ to metallic Pd in addition to considerable reduction of surface Ti cations to Ti3+ and Ti2+ cations; XPS Au4f lines were not affected. Transmission electron microscopic studies indicated that Au particles have a mean particle size of about 3.5 nm while Pd particles are smaller 1–1.5 nm in size. UV excitation of the catalyst in ultrahigh vacuum (UHV) conditions resulted in the formation of acetaldehyde and hydrogen in addition to photodesorption of the reactant ethanol. Hydrogen production, representing ca. 30 % of the desorbing products, was delayed compared to acetaldehyde desorption. This was interpreted as due to kinetic effect whereby initially most electrons transferred to the conduction band are trapped by surface hydroxyls as well inevitable presence of oxygen in the powder accelerating acetaldehyde formation (dehydrogenation). Only once most oxygen-containing species have reacted and molecular hydrogen was formed. To our knowledge, this is the first UHV in situ study of hydrogen production from ethanol photocatalytically over M/TiO2 system.
Tài liệu tham khảo
Fujishima A, Honda K (1972) Electrochemical photolysis of water at a semiconductor electrode. Nature 238:37
Kudo A, Miseki Y (2009) Heterogeneous photocatalyst materials for water splitting. Chem Soc Rev 38:253
Connelly KA, Idriss H (2012) The photoreaction of TiO2 and Au/TiO2 single crystal and powder surfaces with organic adsorbates. Emphasis on hydrogen production from renewable. Green Chem 14:260–280
Nadeem MA, Connelly KA, Idriss H (2012) The photoreaction of TiO2 and Au/TiO2 single crystal and powder with organic adsorbates. Int J Nanotechnol (special edition on nanotechnology in Scotland) 9:121–162
Connelly KA, Wahab AK, Idriss H (2012) Photoreaction of Au/TiO2 for hydrogen production from renewables: a review on the synergistic effect between anatase and rutile phases of TiO2. Mater Renew Sustain Energy 1:1–12
Walter MG, Warren EL, McKone JR, Boettcher SW, Mi Q, Santori EA, Lewis NS (2010) Solar water splitting cells. Chem Rev 110:6446–6473
Yang YZ, Chang CH, Idriss H (2006) Photo-catalytic production of hydrogen from ethanol over M/TiO2 catalysts (M = Pd, Pt or Rh). Appl Catal B: Environ 67:217–222
Wahab AK, Al-Oufi M, Bashir S, Al-Salik Y, Katsiev H, Idriss H (2013) Photocatalyst, method of preparation, photolysis system. World Patent 13T&I0037-WO-PCT (2013); Gulf Cooperation Council (13T&I0037-GC-NP), Serial Number GCC/P/2013/25576 International Procedure (13T&I0037-WO-PCT), Serial Number PCT/IB13/59406
Jovic V, Al-Azria ZHN, Sun-Waterhouse D, Idriss H, Waterhouse GIN (2013) Photocatalytic H2 production from bioethanol over Au/TiO2 and Pt/TiO2 photocatalysts under UV irradiation––a comparative study. Top Catal 56:1139–1151
Waterhouse GIN, Wahab AK, Al-Oufi M, Jovic V, Anjum DH, Sun-Waterhouse D, Llorca J, Idriss H (2013) Hydrogen production by tuning the photonic band gap with the electronic band gap of TiO2. Scientific Rep 3:1–5
Jovic V, Chen WT, Blackford MG, Idriss H, Waterhouse GIN (2013) Effect of gold loading and TiO2 support composition on the activity of Au/TiO2 photocatalysts for H2 production from ethanol–water mixtures. J Catal 305:307–317
Bowker M, Millard L, Greaves J, James D, Soares J (2004) Photocatalysis by Au nanoparticles: reforming of methanol. Gold Bull 37:3–4
Subramanian V, Wolf EE, Kamat PV (2004) Catalysis with TiO2/gold nano composites: effect of metal particle size on the fermi level equilibration. J Am Chem Soc 126:4943–4950
Du L, Furube A, Yamamoto K, Hara K, Katoh R, Tachiya M (2009) Plasmon-induced charge separation and recombination dynamics in gold TiO2 nanoparticles systems: dependence on TiO2 particle size. J Phys Chem C 113:6454–6462
Seh ZW, Liu S, Low M, Zhang SY, Liu Z, Mlayah A, Han MY (2012) Janus Au–TiO2 photocatalysts with strong localization of plasmonic near-fields for efficient visible-light hydrogen generation. Adv Mater 24:2310–2314
Zhang Z, Zhang L, Hedhili MN, Zhang H, Wang P (2013) Plasmonic gold nanocrystals coupled with photonic crystal seamlessly on TiO2 nanotube photoelectrodes for efficient visible light photoelectrochemical water splitting. Nano Lett 13:14–20
Bashir S, Wahab AK, Idriss H (2014) Synergism and photocatalytic water splitting to hydrogen over Pt/TiO2 catalysts: effect particle size. Catal Today (submitted)
http://webbook.nist.gov/Massfragmentationethanol
Kruse N, Chenakin S (2011) XPS characterization of Au/TiO2 catalysts: binding energy assessment and irradiation effects. Appl Catal A 391:367–376
Yi CW, Luo K, Wei T, Goodman DW (2005) The composition and structure of Pd–Au surfaces. J Phys Chem B 109:18535
Li Z, Gao F, Wang Y, Calaza F, Burkholder L, Tysoe WT (2007) Formation and characterization of Au/Pd surface alloys on Pd (111). Surf Sci 601:1898–1908
Moulder JF, Stickle WF, Sobol PE, Bomben KD (1992) Handbook of X-ray photoelectron spectroscopy, Perkin-Elmer Corporation
Idriss H, Barteau MA (1994) Reactions of p-benzoquinone on TiO2(001) single crystal: oligomerization and polymerization by reductive coupling. Langmuir 10:3639–3700
Idriss H, Barteau MA (1994) Characterization of TiO2 surfaces active for novel organic synthesis. Catal Lett 26:123–139
Doniach S, Sunjic M (1970) Many-electron singularity in X-ray photoemission and X-ray line spectra from metals. J Phys C Solid 3:285
Montini T, Marelli M, Minguzzi A, Gombac V, Psaro R, Fornasiero P, DalSanto V (2012) H2 production by renewables photoreforming on Pt–Au/TiO2 catalysts activated by reduction. ChemSusChem 5:1800–1811
Nadeem MA, Murdoch M, Waterhouse GIN, Metson JB, Keane MA, Llorca J, Idriss H (2010) Photoreaction of ethanol on Au/TiO2 anatase. Comparing the micro to nano particle size activities of the support for hydrogen production. J PhotoChem PhotoBiol A: Chem 216:250–255
Muir JN, Choi YM, Idriss H (2012) DFT study of ethanol on TiO2 (110) rutile surface. Phys Chem Chem Phys 14:11910–11919
Idriss H, Kim KS, Barteau MA (1993) Carbon–carbon bond formation via aldolization of acetaldehyde on single crystal and polycrystalline TiO2 surfaces. J Catal 139:119–133
Reztova T, Chang C-H, Koersh J, Idriss H (1999) Dark and photoreactions of ethanol and acetaldehyde over TiO2/carbon molecular sieve fiber. J Catal 185:223–235
Kundu S, Vidal AB, Nadeem A, Senanayake SD, Stacchiola D, Idriss H, Rodriguez J (2013) Ethanol photo reaction on ruthenium metal/metal oxide modified rutile TiO2 (110) single crystal surface. J Phys Chem C 117:11149–11158