Materials World Network: Catalyst Materials Synthesis at Accessible High Temperatures and Pressures

Lehigh University, Bethlehem PA

Investigators

Abstract

This collaborative program between Lehigh University and the University of Cardiff (UK) is directed towards developing alternative, more efficient and greener, preparation strategies for the production of some important oxide based catalyst materials. The major methodologies of mixed oxide heterogeneous catalyst preparation, which have remained unchanged for decades, are precipitation, fusion and impregnation. There are however, an extensive set of reaction conditions (i.e. at elevated temperature >200oC) and pressure (>50 bar) that have remained relatively unexplored. The aim of this project is to investigate the use of accessible high temperatures and pressures for controlled one-step oxide crystallization using (i) an autoclave utilizing three phase (gas/liquid/solid) systems below the critical point and two phase systems above the critical point; and (ii) a high pressure - high temperature tubular flow reactor. In the first instance, the researchers will investigate this set of reaction conditions for the preparation of vanadium phosphorus oxides (VPO). The VPO system represents one of the most extensively studied heterogeneous oxide catalysts and VPO materials are utilized commercially for the selective oxidation of n-butane to maleic anhydride. Proof-of-concept studies on VPO materials have already demonstrated that unusual phases and morphologies, which in some cases are highly catalytically active, can be generated in this high temperature, high pressure reaction regime. This new preparation methodology will be later extended to synthesize niobium and molybdenum phosphates. The research program will combine the expertise of two groups that have a long and very successful record of performing collaborative research together. The UK group, led by Professor Hutchings at Cardiff University, will spearhead research into the new catalyst preparation methodologies and will evaluate the new materials produced as catalysts for alkane oxidation and oxidative hydrogenation reactions. The US group, under the direction of Professor Kiely, using cutting edge electron microscopy and spectroscopy techniques will perform detailed structural characterization of the catalysts produced, with the aim of establishing structure-function relationships. This project will educate young people in interdisciplinary and international research. Students from both countries will visit the partner institutions across the Atlantic for extended periods thus fostering an understanding of cultural nuances and research environments in another country.