Steam reforming of acetic acid on Ni/gamma-Al(2)O(3) with different nickel loading for hydrogen production was investigated in a tubular reactor at 600 degrees C, 1 atm, H2O/HAc = 4, and WHSV = 5.01 g-acetic acid/g-cata.h(-1). The catalysts were characterized by temperature programmed oxidation (TPO) and differential thermal analysis (DTA). X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The results showed that the amount of deposited carbidic-like carbon decreased and graphitic-like carbon increased with Ni loading increasing from 9 to 15 wt%. The Ni/gamma-Al(2)O(3) catalyst with 12 wt% Ni loading had higher catalytic activity and lower coke deposited rate. (C) 2010 Elsevier Ltd. All rights reserved.