Catalytic oxidation is an effective method to remove CO in exhaust gas, yet it is challenging to enhance the H₂O tolerance of catalysts at low temperature due to the strong competitive adsorption between H₂O and reactants (CO and O₂). Here, we report that the precise control of the metal-support interaction by regulating the support crystal plane of Pd/Pr-CeO₂ catalysts leads to highly efficient CO oxidation catalysts under wet conditions. The addition of H₂O inhibits the CO oxidation activity of Pr-CeO₂ nano-cube and octahedron supported highly dispersed Pd catalysts, but enhances the CO oxidation activity over Pr-CeO₂ nanorod supported highly dispersed Pd catalysts. After introduction of H₂O in feed gas, the T₉₉ (Temperature to achieve 99 % conversion of CO) decreases from 157 °C to 115 °C for Pd/Pr-CeO₂-NRs (Nanorods) catalyst at a gas hourly space velocity of 70, 000 h⁻¹ and remains stable for more than 2000 min in the presence of H₂O. Systematic characterization reveals that the (1 1 0) crystal plane of Pr-CeO₂ nanorod enhance the interaction between Pd species and support, resulting in the formation of abundant high dispersed Pd-oxygen vacancy (Ov) active sites. The kinetics study and in-situ DRIFTS characterization confirmed that CO oxidation Pd/Pr-CeO₂-NRs mainly follows the H₂O-mediated Langmuir-Hinshelwood mechanism in the presence of H₂O. H₂O promote the formation of active OH groups and accelerate CO oxidation through formate pathway at low temperature. In contrast, the CO oxidation follow traditional MvK mechanism in the absence of H₂O.

催化氧化是去除废气中CO的有效方法，但由于H ₂ O与反应物（CO和O ₂）之间存在强烈的竞争吸附，提高催化剂在低温下的H _{2 O耐受性具有挑战性。}在这里，我们报道了通过调节 Pd/Pr-CeO ₂催化剂的载体晶面来精确控制金属-载体相互作用，从而在潮湿条件下产生高效的 CO 氧化催化剂。H ₂ O的加入抑制了Pr-CeO ₂纳米立方体和八面体负载高分散Pd催化剂的CO氧化活性，但提高了Pr-CeO _{2的CO氧化活性}纳米棒负载的高度分散的 Pd 催化剂。在原料气中引入 H _{2 O 后，对于 Pd/Pr-CeO 2} -NRs（纳米棒）催化剂，T ₉₉（实现 99% CO 转化的温度）在气时空间下从 157 °C 降至 115 °C速度为 70, 000 h ^{-1并在 H} ₂ O存在下保持稳定超过 2000 分钟。系统表征表明Pr-CeO ₂纳米棒的 (1 1 0) 晶面增强了 Pd 物种与载体之间的相互作用，导致形成丰富的高分散 Pd-氧空位 (Ov) 活性位点。动力学研究和原位 DRIFTS 表征证实了 CO 氧化 Pd/Pr-CeO _{2  -NRs在H 2} O存在下主要遵循H ₂ O介导的Langmuir-Hinshelwood机制。H ₂ O促进活性OH基团的形成并在低温下通过甲酸盐途径加速CO氧化。相反，在没有 H ₂ O的情况下，CO 氧化遵循传统的 MvK 机制。