Reed J. Hendershot

A novel reactor system for high throughput catalyst testing under realistic conditions

This article describes a 16-channel reactor system specifically designed for the high throughput study of supported heterogeneous catalysts under well controlled conditions. Each of the individual channels of the reactor has been designed to operate as an autonomous plug flow reactor without thermal or product cross-talk often associated with other reactors specifically designed for high throughput experimentation (HTE) studies. The flowrate difference between reactors was kept to a minimum through the use of orifices, and the temperature of each channel is continuously monitored. This level of control allows for the measurement of kinetically significant parameters in a high throughput manner. The system is also capable of studying transients occurring on the order of seconds, to further assist in kinetic analysis and understanding. Results are shown for the determination of reaction order during carbon monoxide oxidation over various supported metal catalysts measured under differential conversion.

Multivariate and Univariate Analysis of Infrared Imaging Data for High-Throughput Studies of NH3 Decomposition and NOx Storage and Reduction Catalysts

The application of Fourier transform infrared (FTIR) spectroscopic imaging for the analysis of the reaction products from parallel reactors has been extended to the quantitative analysis of complex infrared (IR) spectra. Multivariate factor-based and univariate calibration models were developed to extract quantitative concentration information from highly overlapped IR spectra. The three multivariate factor-based models of principal component regression (PCR) and partial least squares 1 and 2 (PLS-1 and PLS-2) were employed. The effects of the number of coadded mirror scans used in the data collection and the number of factors used in the data analysis on the predictive ability of this multivariate approach were characterized. The effectiveness of these approaches is demonstrated through application to the high-throughput study of ammonia decomposition and NOx storage and reduction catalysts.

Spectroscopic Imaging in the Mid-Infrared Applied to High-Throughput Studies of Supported Catalyst Libraries

The “combinatorial approach” has shown very promising results for pharmaceuticals and small organic molecules [1, 2, 3]. High-throughput (HT) screening of heterogeneous catalysts goes back at least IS years [4], but has recently been rediscovered as a method for rapidly and efficiently identifying catalyst formulations [5, 6, 7, 8, 9, 10, 11, 12, 13, 14]. The approach consists of two key steps: the systematic synthesis of a large number of potentially useful formulations (collectively referred to herein as a “library,” although this term has recently been contested [15), and the subsequent rapid testing of this library to determine the usefulness of each formulation to the specific application. Several methodologies have been developed for the rapid and efficient generation of catalyst libraries, ranging from evaporation methods [16] and robotic dispensing of catalyst precursors [17–19] to parallel hydrothermal processing [20, 21, 22]. Once generated, the libraries must be characterized and tested. For heterogeneously catalyzed reactions, this step can range from simple qualitative activity screening to the quantitative measurement of selectivity or turnover rates. Currently available analytical techniques are often incapable of keeping pace with the large numbers of compounds created. This creates a bottleneck, slowing the entire discovery process, and has created a serious demand for the development of analytical techniques specifically designed for the HT analysis of combinatorial heterogeneous catalyst libraries.