Vanadium Phosphate Catalyst Precursors Prepared using a New Di-block Copolymer Templating Method

Christopher J. Kiely, Lehigh University, DMR 0709887

Vanadium phosphorus oxide (V-P-O) catalysts are used commercially for the conversion of n-butane to maleic anhydride. The V-P-O catalyst precursor (VOHPO4·0.5H2O phase) is usually prepared via a method whereby isobutanol is used as both a solvent and reductant for V2O5, and H3PO4 is used as the source of phosphorus.

We have discovered that the addition of PSMA (2-poly (styrene-alt-maleic acid)), a di-block copolymer, during the preparation procedure can strongly influence the final morphology and crystallinity of the V-P-O catalyst precursor.

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis (see figure) indicates that the V-P-O platelets tend to develop more well defined rhomboidal shapes and have better crystallinity when an increasing amount of the PSMA polymer template is added. Furthermore, these modified V-P-O materials can be fully activated for use in just a few hours as compared to the 100 hours typically required for commercial V-P-O precursors derived from the standard preparation route.

SEM (column 1) and TEM (column 2) micrographs of the V-P-O catalyst precursors prepared in the presence of an increasing amount of PSMA template.

PSMA: V2O5

weight ratio

0

1:260

1:130

1:65

Increasing amount of

PSMA

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

Christopher J. Kiely, Lehigh University, DMR 0709887

International Research CollaborationResearchers from Cardiff University (UK) are preparing complex oxide catalysts (e.g. V-P-O) by completely new synthesis routes. Lehigh University (USA) are using state-of-the-art X-ray and electron microscopes to analyze the micro- and nano-structures of these materials.

Educational OutreachPart of the MWN collaboration involves swapping personnel between the UK and USA institutions. Senior Cardiff researchers have already attended the world renowned Lehigh Microscopy School on SEM analysis.

Broader Impact of the ResearchV-P-O catalysts are used commercially in the manufacture of maleic anyhdride (MA) which is an important constituent in agrochemicals, lubricants, lycra and even mouthwashes. The ability to develop new structural forms of the V-P-O materials by novel preparation methods may lead to catalysts having a higher productivity. New preparation techniques such as seeding, polymer templating and high pressure synthesis are under investigation in this Materials World Network program.

V-P-O catalyst

A commercial MA plant Products made from MA