Skip masthead and go to main navigation, secondary menu or main content.
Search This Site | People | Departments | Penn State
Skip masthead and go to main navigation, secondary menu or main content.
Search This Site | People | Departments | Penn State
Vadim V. Guliants
Department of Chemical and Materials Engineering
University of Cincinnati
Thursday, January 24, 2008
102 Chemistry Building
10:00 a.m. - 11:00 a.m.
Abstract
Conversion of fossil fuels and biomass into a mixture of H2 and CO, known as syngas, is an important intermediate step in many existing and emerging energy conversion technologies, most importantly H2 production by steam or aqueous phase reforming and partial oxidation over supported Ni catalysts.
However, the supported Ni catalysts deactivate due to sintering and conventional approaches to improve their deactivation resistance have encountered severe fundamental limitations, which in turn, have serious implications for the development of improved reforming processes.
We have recently discovered a new class of high surface area Ni0-based catalysts obtained via the self-assembly of heterometallic alkoxides, e.g. M5TiO(OEt)6 (M= Ni, Co, Mg, Al), in the presence of oligomeric alkyl-ethylene oxide surfactants.
We discuss our preliminary data indicating that these Ni0 catalysts possessed significantly improved sinter resistance under high temperature steam/H2 conditions as compared to current Ni catalysts due to a unique adhesion effect at the Ni/M oxide interface. Therefore, these nanostructured Ni0 catalysts represent a novel and highly promising class of catalysts for elucidating the bulk and surface molecular structure-reactivity/selectivity relationships in reforming reactions which will enable the rational design of improved Ni-based catalysts for these energy conversion technologies.
The current abundance of light alkanes has generated much recent interest in their catalytic conversion to olefins and nitriles in the petrochemical industries which represents the shift in technology from petroleum-based olefin feedstocks to environmentally friendly natural gas-based alkanes. In the past few years, there has been a significant growth in the number of industrial patents and publications on one-step propane ammoxidation to acrylonitrile (ACN), a top 50 chemical in the US, over several promising bulk Mo-V-M oxides. However, the current fundamental understanding of these catalysts is rather limited which has serious implications for the development of a one-step process for propane ammoxidation to ACN, since there is essentially no scientific basis that can assist in the design of improved Mo-V-M-O catalysts.
We discuss our recent studies of the catalytic roles of crystalline Mo-V-M-O phases, their topmost surface compositions and the nature of the active and selective surface sites present in this unique catalytic system capable of selectively catalyzing three alkane transformation reactions, namely propane ammoxidation to ACN, propane oxidation to acrylic acid and oxidative dehydrogenation (ODH) of ethane. Fundamental advances in understanding the surface molecular structure-reactivity relationships for this unique system offer a possibility of not only rational design of propane ammoxidation catalysts, but also expanding the scope of selective alkane (amm)oxidation beyond the limited number of feedstocks that have met with technological and commercial success.