Selective hydrogenolysis of glycerol over Ir-Ni bimetallic catalysts

The effect of the addition of Ni to Ir/γ-Al2O3 was studied for glycerol hydrogenolysis reaction. The catalysts were characterized by textural analysis, XRD, H2-TPR, XPS and TEM. In all cases, the addition of Ni to Ir/γ-Al2O3 produced a significant increase in glycerol conversion, and a high selectivity to 1,2-PDO was maintained. TOF values increased from 0.4 × 10−2 s−1 for Ir monometallic catalyst, to 4.3 × 10−2 s−1 for bimetallic IrNi2_C catalyst. The latter was the most active catalyst among the calcined bimetallic catalysts. Selectivity to 1,2-PDO had an insignificant decrease from 89.9% for Ir monometallic catalyst to 83.1% for IrNi2_C catalyst. However, non-calcined IrNi2 catalyst presented a TOF value of 1.3 × 10−2 s−1. This result indicates that the calcination step was fundamental to obtain a strong Ir-Ni interaction that lead to better performances of the bimetallic catalysts. Ir-Ni interaction was evidenced by XPS analyses of the calcined series of catalysts, where the presence of an Irδ+ species was observed (0 < δ < 4), suggesting an electronic density transferring from Ni to Ir.