Hydrocracking technology is important for producing high-value naphtha from a wide range of refinery feedstocks. The preparation method of Ni-W catalysts can make a large difference in the sulfidability of the metals which affects catalyst performance. Detailed EXAFS study with TEM and TPR measurements elucidate the metal behavior in these catalyst materials.

Kelly, S. D., Yang, N., Mickelson, G. E., Greenlay, N., Karapetrova, E., Sinkler, W. and Bare, S. R. (2009). "Structural characterization of Ni-W hydrocracking catalysts using in situ EXAFS and HRTEM." Journal of Catalysis 263(1): 16-33.

Detailed EXAFS analysis confirms tin substituted into the zeolitic framework. Often, this is all the information obtained —a first-shell fit consistent with a framework species versus a non-framework one. However, by analyzing higher-shell data to 5 Å the site in the zeolite framework is determined. It may be that the unique selectivity of this catalyst in Baeyer-Villiger oxidation reactions is due to the spatially uniform distribution of tin in the zeolite framework.

Bare, S. R., S. D. Kelly, W. Sinkler, J. J. Low, F. S. Modica, S. Valencia, A. Corma and L. T. Nemeth (2005). "Uniform catalytic site in Sn-beta-zeolite determined using X-ray absorption fine structure." Journal of the American Chemical Society 127(37): 12924-12932.

A plug-flow reactor cell capable of operation at 873 K and 14 bar. It is similar to a quartz capillary cell, but the reactor tube is fabricated from beryllium. The thermocouple is embedded within the catalyst bed so that the actual catalyst temperature is measured. The tube is heated by a controlled flow of hot air or nitrogen. Beryllium is robust and its strength is not sensitive to small scratches like quartz capillaries. The absorpiton length of the sample can be adjusted by choosing a beryllium tube of the appropriate diameter. Beryllium has low adsorption so that samples with low energy edges can be measured.

Bare, S. R., N. Yang, S. D. Kelly, G. E. Mickelson and F. S. Modica (2007). "Design and operation of a high pressure reaction cell for in situ X-ray absorption spectroscopy." Catalysis Today 126(1-2): 18-26.

Yang, N., G. E. Mickelson, N. Greenlay, S. D. Kelly and R. Bare (2007). In Situ EXAFS of Ni-W Hydrocracking Catalysts. 13th International Conference on X-ray Absorption Fine Structure. B. Hedman and P. Pianetta. Melville, NY, AIP Conf. Proc. 882: 663-665.