XPS characterization of hydroquinone-treated hematite
EMSL Project ID
2554
Abstract
We are studying the adsorption and reaction of hydroquinone with hematite mineral surfaces in connection with questions regarding biological electron transport for iron reducing bacteria. Our primary goal in the proposed work at PNNL is to look for reduction of surface Fe from Fe(III) to Fe(II) as a result of adsorption of hydroquinone to the hematite surface. We have conducted a number of electrochemical STM investigations that confirm a reproducible change in surface unit cell in the presence of hydroquinone, and perhaps in the presence of AQDS (anthroquinonedisulfonate). The pattern is very similar to that observed previously for hydroquinone on Pd, and prompts questions concerning the possible formation of an organometallic surface complex. This would be quite surprising unless the surface Fe is reduced. Hence, we want to look for substantial Fe(II) at the surface in the presence of adsorbed hydroquinone. We envision, at one end of the complication spectrum, that Andrew Stack (the Ph.D. student working on the project; he has visited PNNL previously in working with Dr. Kevin Rosso) would visit with a small number (3 or 4) samples of hematite, reserve one in case there are problems with any of the others, and obtain a survey XPS spectrum (to perhaps 1000 eV binding energy) and narrow spectra of the Fe 2p, O 1s, and C 1s regions, for three samples: one clean, and two treated just prior to introduction to the spectrometer in hydroquinone solutions. Given my previous experience with XPS and the restricted nature of our question, we anticipate that this work would take no more than a day unless there are large unanticipated problems.
Project Details
Project type
Exploratory Research
Start Date
2002-07-08
End Date
2003-07-08
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Stack AG, CM Eggleston, and MH Engelhard. 2004. "Reaction of Hydroquinone with Hematite I. Study of Adsorption by Electrochemical-Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy." Journal of Colloid and Interface Science 274 (2004)(2):433-441.
Stack AG, KM Rosso, CM Eggleston, and DM Smith. 2004. "Reaction of Hydroquinone with Hematite II: Calculated Electron Transfer Rates and Comparison to the Reductive Dissolution Rate." Journal of Colloid and Interface Science 274(2):442-450.