ZrO2-Supported H3PW12O40 (HPW) catalysts were used to catalyze the dehydration of glycerol to produce acrolein at 315 degrees C under a high space velocity (GHSV(Glycerol) = 400 h(-1)). The catalysts were prepared by varying the loading of HPW on two ZrO(OH)(2) supports of different preparations, followed by calcination in flowing nitrogen. The use of alcogel-derived ZrO(OH)(2)-AN for the support, compared with conventional hydrogel-derived ZrO(OH)(2)-CP, produced HPW/ZrO2 catalysts that showed higher surface areas and better catalytic performance for the selective formation of acrolein from glycerol dehydration. Independent of the preparation history of ZrO2, the Keggin-anion density (HPW nm(-2)) at the catalyst surface appeared as a key to the selectivity and mass-specific activity of HPW for acrolein production. Acrolein selectivity as high as 70 mol% was obtained over the catalysts having the intermediate densities (0.18-0.65 HPW nm(-2)), at which most of the Keggin HPW remained intact after calcination up to 650 degrees C. At higher densities, destruction of the Keggin HPW would occur during the calcination, which led to lower acrolein selectivity. High selectivity (71 mol%) and high yield (>= 54%) for acrolein production were found sustainable over the best performing HPW/ZrO2-AN catalyst for reaction times up to 10 h. (C) 2008 Elsevier B.V. All rights reserved.