One novel modification in preparing high surface area VPO catalyst was established by applying polyethylene glycols (PEGs) as the unique additives. The PEG-derived samples possessed considerably high surface areas of 41-54m(2)/g, with the average particle size of 100-200 nm and well crystallized (VO)(2)P2O7 phase, showing notably improved performances for the partial oxidation of n-butane to maleic anhydride (MA) even at lower reaction temperature. The principle function of PEG in preparation chemistry and the possible origins of the enhanced performance were preliminarily discussed. Another modification in preparing high surface area VPO catalyst adopted in this study was the combination of synthesizing high surface area VPO precursor by well-controlled addition of phosphoric acid, thermal pre-treating the precursor at certain temperature and ball milling in cyclohexane. The so-obtained catalysts also showed pronounced catalytic performance. The applied milling process not only effectively increased the surface areas of the milled samples and consequently the available number of active sites, but also somehow changed other sample characteristics such as the local environment and the redox behavior; which may also be responsible for the overall performance enhancement. (C) 2003 Elsevier B.V. All rights reserved.