title: Photoelectrochemical hydrogen production on α-Fe2O3 (0001): insights from theory and experiments.
abstract: The photoelectrochemical (PEC) decomposition of organic compounds in wastewater is investigated by using quantum chemical (DFT) methods to evaluate alternatives to water splitting for the production of renewable and sustainable hydrogen. Methanol is used as a model organic species for the theoretical evaluations of electrolysis on the surface of the widely available semiconductor hematite, α-Fe2 O3 , a widely studied photocatalyst. Three different α-Fe2 O3 surface terminations were investigated, including the predominant surface found in aqueous electrolytes, (OH)3 R. The PEC oxidation of methanol is energetically downhill, producing CO2 and protons. The protons are reduced to hydrogen on the cathode. Experimental PEC measurements were also performed for several polyalcoholic compounds, glycerol, erythritol, and xylitol, on α-Fe2 O3 as the photocatalyst and showed high incident-photon-to-current-efficiencies (IPCE) that were much greater than those of water splitting. Interestingly, high IPCEs were observed for hydrogen production from polyalcohols in the absence of any applied bias, which was not thought to be possible on hematite. These results support the potential application of PEC for hydrogen production by using widely available hematite for the PEC oxidation of selected components of organic wastewater present in large quantities from anthropogenic and industrial sources.
authors.affiliation: PhotoCatalytic Synthesis Group, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, Meander 229, P.O. Box 217, 7500 AE Enschede, The Netherlands, Fax: (+31) 53-489-3968; Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242 (USA). j.baltrusaitis@utwente.nl.
authors.forename: Jonas
authors.initials: J
authors.lastname: Baltrusaitis
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Hu
authors.forename: Eric W
authors.initials: EW
authors.lastname: McFarland
authors.forename: Anders
authors.initials: A
authors.lastname: Hellman
mesh_terms: D004563:Electrochemistry; D004572:Electrolysis; D005290:Ferric Compounds / Q000737:chemistry* / Q000528:radiation effects; D006859:Hydrogen / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry / Q000528:radiation effects; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D014874:Water Pollutants, Chemical; C000499:ferric oxide; D006859:Hydrogen; D014025:Titanium; D000432:Methanol
keywords: density functional calculations; electrochemistry; hematite; hydrogen; photochemistry