Effect of boron on the stability of Ni catalysts during steam methane reforming

Ni catalysts promoted with 0.5 and 1.0 wt% boron were synthesized, characterized and tested during steam methane reforming, to evaluate the effect of boron on the deactivation behavior. Boron adsorbs on the gamma-Al2O3 support and on the Ni particles and 1.0 wt% boron is found to enhance the stability without compromising the activity. Catalytic studies at 800 degrees C. 1 atm, a stoichiometric methane to steam ratio, and space velocities of 330,000 cm(3)/(hg(cat)) show that promotion with 1.0 wt% boron reduces the rate of deactivation by a factor of 3 and increases the initial methane conversion from 56% for the unpromoted catalyst to 61%. Temperature-programmed oxidation (TPO) and scanning electron microscopy (SEM) studies confirm the formation of carbonaceous deposits and illustrate that 1.0 wt% boron reduces the amount of deposited carbon by 80%. (C) 2008 Elsevier Inc. All rights reserved.