by: X. Deng, D. Pinnaduwage, A. R. Alemozafar, B. K. Min
Gold has been considered to be inert metal for catalytic reactions whereas small gold clusters supported on metal-oxides were found to be active catalyst for several oxidative reactions. Recently, however, we have found that an extended gold surface such as Au(111) single crystal is also active for the oxidation once the surface can be populated by oxygen atoms. We developed and used two methods of deposition of oxygen atoms on Au(111) surface: electron induced NO 2 
dissociation and ozone decomposition. The characteristics of the surface was well investigated previously by STM, LEED, HREELS, and XPS. Using this well defined oxygen covered Au surface several oxidative reactions (e.g. CO and furan) are being investigated.
by: James Williams and A. R. Alemozafar
Many advances in carbon-based electronics have taken place over the last decade. Carbon nanotubes have become a staple of experimental studies of electronic transport through molecular systems. On a more fundamental level, transport studies of single graphene will help to solidify the basis of knowledge of the electronic properties of nanotubes and help to explain some of the known theoretical phenomena in graphene sheet. I hope to make electrical measurements of graphene sheets to gain insights into potential use as a transistor and as a basis for a multi-transistor circuit. This research is done in collaboration with fellow graduate student Ryan Quiller, post-doctoral student Byoung Koun Min, and professor Cynthia Friend, Charles Marcus and Venky Narayanamurti.
In addition to carbon based materials, I have recently been involved with surface science projects involving Ti and Water. In these experiments, we used XPS to study the effects of H2O on Ti nanoparticles that were evaporated on Au(111). Post-doctoral student Ali Reza Alemozafar has perform STM on these particles in hopes to understand novel XPS features we observe. We plan on continuing this research using electron energy loss spectroscopy (EELS).
Molecular Interactions with Water on Oxide Surfaces
by: Ryan Gordon Quiller
Reactions of NO x , SO 2 , O 3 , and oxygenated hydrocarbons on oxide surfaces in high relative humidity are important in areas such as atmospheric chemistry and environmental catalysis. We are investigating the reactivity of thin oxide films such as Fe 2 O 3 and Al 2 O 3 in the presence of water. We hope to gain further insight into the effect of OH and H 2 O on gas-oxide surface reaction rates, mechanisms, and products. Also, we are studying how these molecular interactions are affected by materials properties of the oxide films such as terrace widths and defects. Our research involves reflection absorption infrared spectroscopy, temperature programmed reaction spectroscopy, x-ray photoelectron spectroscopy, and scanning tunneling microscopy.
Stranski-Krastanov growth of iron oxide on Pt(111). Image taken from W. Ranke, M. Ritter, and W. Weiss, Phys. Rev. B 60 , 1527 (1999).
Mineral Surface Photoelectrochemistry to Reduce Inorganic Carbon and Form the Prebiotic Soup ineral Surface Photoelectrochemistry to Reduce Inorganic Carb
by: Xiang Zhang, Scot Martin, Cynthia Friend, Martin Schoonen
This research is funded by: NASA Exobiology Program The Prebiotic Soup
Project Overview:
How did life begin?
We are investigating mineral surface photoelectrochemistry as a pathway to reduce inorganic carbon and form a prebiotic soup of organic precursors to life. Basic project questions are: What C x H y O z S a N b molecular products result from CO and CO 2 photoreduction over semiconductor supports? What important synthesis reactions relevant to prebiotic chemistry, which are otherwise "no go" via thermal pathways, become possible through semiconductor photocatalysis? Relevant semiconductors for early Earth include ZnS, TiO 2 , ZnO, and MnS. The list expands for chemistry occurring on interstellar dust, which may have seeded organic molecules into the prebiotic soup.
http://www.deas.harvard.edu/environmental-chemistry/projects/prebiotic.php
Molybdenum Oxide
by: Xiaoying Liu
Molybdenum oxide, MoOx, is a prototypical material which is widely used as catalysts in both fundamental research and chemical industry. It shows unique spreading behavior on various oxide and metal supports, which enables the formation of 3D nanoclusters or 2D thin films of molybdenum oxide. Combining the variable stoichiometry of MoOx, oxygen vacancies on surface and size-dependent surface area, these materials have great potential in surface catalysis, for example partial oxidation of alkanes. Material preparation, structural characterization, and catalytic investigation all make this project interesting and exciting.
Microscopic Mechanisms of Dissolution and Precipitation of Manganese Minerals
by: Young-Shin Jun
Manganese oxide minerals in surface and ground waters dissolve as Mn 2+ (aq) and precipitate as Mn(III) and Mn(IV) oxides in response to natural and anthropogenic cycles of aqueous pE and pH conditions. Increases in P(O 2 ) and pH favor precipitation. When precipitating, the Mn(III) and Mn(IV) oxides form thin coatings on mineral surfaces, including metal carbonates. This film formation significantly impacts the precipitation and dissolution rates in natural waters of both the substrate mineral and the Mn oxide coating. Furthermore, given the essential role of Mn as a redox active species and as a scavenger by co-precipitation) of heavy metals (e.g., Cd, Zn, Co, Cu, Ni, Pb, and As), Mn oxide precipitation and dissolution impact pE conditions, nutrient availability, and contaminant fate and transport. In order to understand the microscopic mechanisms of precipitation and dissolution of manganese minerals, I use atomic force microscope (AFM) in the presence of organic acids and heavy metal ions. I also worked at Argonne National Laboratory in Chicago to determine the structure of a Mn oxide film grown on several carbonate minerals using synchrotron-based measurements such as crystal truncation rods (CTRs) and GI-XANES.