Reactors
Liquid Phase Flow Reactors -
We have built and tested several liquid phase flow reaction kinetics apparatus for the catalytic upgrading of water-soluble, biomass-derived organic molecules. The catalyst is loaded in 1/4 or 1/2 inch stainless steel reactors. HPLC pumps are used to supply the reactor with liquid feed. Hydrogen or (or other) gas can also be fed to the reactor. The system operates at pressures up to 1000 psig (the pressure is controlled by the backpressure regulator). The liquid effluent from the reactor is collected in a gas-liquid separator. The effluent gas stream is analyzed on-line by GC. The separator is periodically drained and the organic and liquid phases are analyzed off-line using GC and HPLC.
Parr Batch Reactors -
We currently have five 50 mL, two 300-mL, two 500-mL, and one 2-L stirred batch Parr Reactors. The reactors are capable of operating at temperatures up to 490 K and pressures up to 3000 psig, and one is configured to operate at temperatures up to 573 K. The 50-mL reactors are stirred with magnetic stirrers (0-600 rpm), and the larger reactors are stirred using motor-driven impellers. Each has a liquid sampling valve so that samples can be withdrawn during operation. Reaction products are identified by GC or HPLC. Additionally, one 50-mL Parr Reactor is configured to accept an ATR-IR probe, allowing in-situ monitoring of reactions.
Glass Batch Reactors -
We have configured several hot plates with oil baths that accept 10-mL glass batch reactors for small-volume reaction studies. The reactors are capable of operating at temperatures up to 443 K. They are stirred magnetically (0-1000 rpm). Reaction products are identified by GC or HPLC.
Spectroscopy
Microcalorimetry -
We currently have several Tian-Calvet type heat-flux calorimeters for studies of adsorption processes on supported metal catalysts. For example, we have an automated Setaram C-80 calorimeter for determination of heats of adsorption at temperatures from 300 to 570 K, and we have a Setaram BT-215 low-temperature calorimeter that can be used at temperatures between 77 to 470 K.
Infrared Spectroscopy -
We have a Thermo Nicolet 6700 FTIR spectrometer. We have constructed FTIR cells that allow in-situ studies over a range of temperatures from 77 to 800 K. We also have an in-situ Attenuated Total Reflectance (ATR) cell that allows us to study the surface properties of metal oxides or supported metal catalysts in aqueous environments at temperatures up to 470 K and pressures up to 600 psig. This cell is connected to an apparatus similar to our reaction kinetics units, which allows ATR-IR spectra to be collected with the sample under flowing liquid samples at reaction temperatures and pressures.
Electron Microscopy -
A number of electron microscopes are available for this research through the Material Science Center at the University of Wisconsin, including a Phillips CM 200 high resolution transmission electron microscope (TEM), a HB 501 scanning transmission electron microscope (STEM) equipped with a X-ray microanalysis, electron energy loss spectroscopy and micro-diffraction, and a LEO Gemini field emission scanning electron microscope (SEM) equipped with X-ray microanalysis.
UHV Capabilities -
In collaboration with Professor Kuech in the Department of Chemical Engineering, we have a UHV system fitted with the Omicron Multiprobe S model STM, with liquid He/N2 cooling and resistive heating over a temperature range of 50-900K. An Omicron EA 125 HR U5 electronic spectroscopy unit provides XPS and AES capabilities. The apparatus is equipped with an Inficon Transpector 2 residual gas analyzer for temperature programmed desorption and reaction measurements. An attached preparation chamber is outfitted with a SPECS USA Model 11/35 Ar-ion sputter gun for UHV sample cleaning and an Oxford Applied Research model EGN4 evaporator for sequential deposition of up to four metals, monitored by quartz crystal deposition controller. Structural characterization of samples can be accomplished with a Staib Instruments RHEED 15 electron diffraction system. Both chambers are fitted with Pfeiffer TMU 261 turbopumps, Varian Vaclon Plus ion pumps, and titanium sublimation pumps, for base pressures below 10-10 torr. We also have built a sample chamber that allows samples to be pretreated under controlled conditions (pressures up to 1 atm and temperatures up to 770 K), followed by transfer to the vacuum chamber for analysis without exposure to air.
Analytical
GC -
We have various gas chromatographs (GC) which have a variety of detectors including thermal conductivity detectors (TCD), flame ioniziation detectors (FID) and a mass spectrometry detector (MS). The GCs contain on-line sampling valves as well as injection ports for off-line analysis.
HPLC -
We currently have four high performance liquid chromatographs (Waters 2695 separations module) with autosamplers, Refractive Index detectors (410 Differential Refractometer), and UV detectors (2998 Photodiode Array).
TOC -
We have access to a total organic carbon (TOC) analysis instrument (Shimadzu TOC-6001 with autosampler) in the Water Chemistry Department at the University of Wisconsin-Madison. This unit allows us to analyze the aqueous phase products of our reactions for total carbon content.
NMR -
We have access to eight different NMR spectrometers at the Magnetic Resonance Facility in the Chemistry Department of the University of Wisconsin-Madison, allowing us to perform routine and non-routine 1H and 13C experiments for identification of reaction products.
Other Catalyst Characterization Equipment -
Most of the techniques typically used in catalyst characterization studies are available at the UW-Madison. These techniques include chemisorption, X-ray diffraction, magnetic susceptibility, BET surface area measurement, X-ray photoelectron spectroscopy, thermo-gravimetric analysis and laser Raman spectroscopy.
