The effect of Cs content in CsxH3-xPW12O40 on the catalytic performance of the reduced Ni-CsxH3-xPW12O40/Al2O3 catalysts for hydrocracking of n-decane with the presence of thiophene and pyridine is studied. The catalysts were characterized by BET, XRD, in situ XRD, Raman, H-2-TPR, H-2-TPD, NH3-TPD and FT-IR of pyridine adsorption. The best result was obtained on 8%Ni-50%CsH2PW12O40/Al2O3 catalyst which shows the highest catalytic activity and with tolerance to 525 ppm of thiophene and 170 ppm of pyridine (the reaction conditions: 2.0 MPa, LHSV = 2.92 h(-1), H-2/n-decane 1500 vol/vol at 300 degrees C). The high catalytic performance of the catalyst may be due to the proper balance between metal and acid functions by adding a certain proportion of Cs to the system. (C) 2012 Elsevier B.V. All rights reserved.