A series of SAPO-41A zeolites with different silicon contents was hydrothermally synthesized from, a new route by using phosphorous acid (H3PO3) as a phosphorus source. They were characterized by XRD, SEM, ICP, IR and NH3-TPD. The silicon content which was incorporated into the framework affected not only the acid sites but also the acid strength of SAPO-41A. The excellent performance of the hydroisomerization of n-decane can be obtained over SAPO-41A with proper silicon content in the framework. Bifunctional catalysts consisting of platinum supported on different types of zeolite (SAPO-41A, SAPO-41B, SAPO-11, MCM-22, HP) were investigated for the hydroisomerization of n-decane. Pt/H beta and Pt/MCM-22 catalysts exhibited a higher hydrocracking activity due to their strong acid sites. The SAPO-based catalysts showed better catalytic performance for the hydroisomerization of n-decane, which can be primarily ascribed to their weaker and more suitable acid strength. Especially the SAPO-41A catalysts showed the highest hydroisomerization activity and selectivity among the SAPO-based catalysts. This is because their pore dimensions are larger than those of SAPO-11 and their grain sizes are smaller than those of SAPO-41B. Furthermore, some important variables affecting the activity and selectivity of a Pt/SAPO-41A catalyst, such as reaction parameters and metal content, were investigated. The conversion of n-decane was 84.04-92.29%, and the selectivity to isomers reached 90.50-85.30% over a 0.5 wt.% PUSAPO-41A3 catalyst when the reaction was performed at 310-330 degrees C. This can be attributed to the catalyst's suitable acid strength, distinct channel dimension, small crystal size and the proper ratio of the acid sites to the metallic sites. (c) 2005 Elsevier B.V. All rights reserved.