Ir-Fe bimetallic catalysts for glycerol hydrogenolysis

The effect of the addition of Fe to an Ir/γ-Al2O3 catalyst in different Fe/Ir molar ratios (0.5; 1.0 e 2.0) on the conversion and selectivity of the glycerol hydrogenolysis reaction was investigated. Additionally, the effect of the calcination of the catalysts was evaluated. The catalysts were prepared by incipient wetness impregnation of the Ir and Fe salts on the support and were characterized by textural analysis, DRX, TPR and XPS techniques. The interaction between Ir and Fe was evidenced in the characterization of the catalysts. The addition of Fe to the Ir catalyst produced an increase in the activity, Table 1, however, this effect was observed only for non-calcined catalysts series. Fe monometallic catalysts presented a very low activity (0.1% of conversion). Calcined catalysts series did not present significant increase in glycerol conversion and selectivity to 1,2-PDO. The calcination process of the bimetallic catalysts may have led to the sintering of metals, leading to conversions and low reaction rates in comparison to the non-calcined bimetallic catalysts. For non-calcined bimetallic catalysts, the conversion increased from 7 to 21.5% for IrFe2/γ-Al2O3 and selectivity to 1,2-PDO remained high (90,1%). Contrary to what was observed with the Ir-Ni bimetallic catalysts in previous work [1], the reaction course could have been determined by structural effects rather than synergistic effects.