A series of MoO_x-promoted Ir/BN catalysts were tested for liquid phase selective hydrogenation of crotonaldehyde. The MoO_x-promotion could significantly improve the reactivity up to 5-fold. Such improvement was mainly due to the formation of Ir-MoO_x interfacial sites in the promoted catalyst, which accelerated the adsorption and activation of crotonaldehyde molecule as evidenced by a much lower activation energy (18.9 kJ mol⁻¹ on the 0.3Mo-3Ir/BN versus 38.4 kJ mol⁻¹ on the 3Ir/BN). The kinetic results revealed negative reaction order of crotonaldehyde (up to -1.1) and high reaction order of H₂ (up to 2.2), indicating the high coverage of crotonaldehyde on the catalyst surface suppressed the adsorption of H₂ due to its low solubility in the liquid phase. Therefore, the adsorption and activation of H₂ on the catalyst might be the rate determining step. However, the preferred adsorption of crotonaldehyde on the Ir-MoO_x interface alleviated the suppression of H₂ adsorption, which was another reason for the higher activity.

测试了一系列 MoO _x促进的 Ir/BN 催化剂用于巴豆醛的液相选择性加氢。MoO _x促进可以显着提高反应性高达 5 倍。这种改进主要是由于在促进催化剂中形成了 Ir-MoO _x界面位点，这加速了巴豆醛分子的吸附和活化，这可以通过低得多的活化能（18.9 kJ mol ^-1在 0.3Mo-3Ir/ BN 与3Ir/BN 上的38.4 kJ mol ^-1）。动力学结果显示巴豆醛的负反应级数（高达 -1.1）和 H _{2 的}高反应级数（高达 2.2），表明巴豆醛在催化剂表面的高覆盖率抑制了 H ₂的吸附，因为它在液相中的溶解度低。因此，催化剂上H ₂的吸附和活化可能是速率决定步骤。然而，巴豆醛在 Ir-MoO _x界面上的优先吸附减轻了对 H ₂吸附的抑制，这是较高活性的另一个原因。