Home – Home – Jornals – Chemistry for Sustainable Development 2025 number 5

The effect of indium oxide additive on the properties of Pd-containing catalytic systems Pd/WO₃-ZrO₂ based on zirconia modified with tungstate anions (tungstated zirconia catalysts) and Pd/WO3-ZrO₂/Al₂O₃ catalysts in which the active component WO₃-ZrO₂ providing the acid properties of catalysts is introduced into the porous matrix of the alumina support is investigated. It is shown that the introduction of indium oxide additive in an amount of 0.5-1.5 wt% into the catalyst composition enhances their activity and also increases the yield of the target reaction products - octane isomers. The introduction of 0.5 wt% indium oxide into the composition of tungstated zirconia catalysts supported on alumina leads to an increase in octane conversion by 5.8 % and a rise in the yield of the target reaction products - octane isomers by 4.7 wt%. For Pd/WO₃-ZrO₂ catalysts, the introduction of indium oxide additive in an amount of 1.0-1.5 wt% leads to an increase in octane conversion by 28.0-38.7 %, with a rise in the yield of isomers by 17.0-21.3 wt%. The positive modifying effect of indium oxide additive to the Pd/WO₃-ZrO₂ catalysts is due to an increase in the proportion of the active tetragonal phase of zirconia from 33 to 43-63 %, a rise in the specific surface area from 28 to 38-40 m²/g and an increase in total acidity according to temperature-programmed desorption of ammonia from 113 to 122 μmol/g. The introduction of the active component into the porous alumina support causes an increase in the proportion of weak acid sites of the catalysts, which provides an increase in selectivity to octane isomers. The addition of indium oxide allows regulating the phase composition, textural characteristics and acid properties of palladium-containing tungstated zirconium catalysts, which determines their catalystic activity, and allows obtaining active and selective catalysts of octane isomerization - Pd/In₂O₃-WO₃-ZrO₂ and Pd/In₂O₃-WO₃-ZrO₂/Al₂O₃.