Hydrogen production from steam reforming of acetic acid over Pt-Ni bimetallic catalysts supported on ZrO2

Acetic acid, a model compound of bio-oil, was chosen to investigate the H-2 production from steam reforming reaction using Pt and Ni catalysts supported on ZrO2. Ni crystallite sizes decreased with addition of Pt (from 23 to 15 nm), increasing the metallic dispersion (from 4.4 to 6.5%). A spillover effect was identified in bimetallic catalysts and caused a significant decrease of Ni reduction temperature. Although the Ni crystallite size in 15Ni/ZrO2 is larger, it showed 100% of conversion and the highest H-2 yield (about 30%) during 30 h of reaction at 500 degrees C. In contrast to what was expect, the performance of bimetallic catalysts was not so good when compared to the monometallic Ni catalyst. 5Pt15Ni/ZrO2 and 1Pt15Ni/ZrO2 showed about 20% of H-2 yield at the end of reaction. 1Pt/ZrO2 presented the worst catalytic performance; it produced more acetone, which can be correlated to its higher acidity, and deactivated very fast, with the highest coke formation rate. Coke was predominantly amorphous for all catalysts.