National Engineering Research Centre of Chemical Fertilizer Catalyst, Fuzhou University, Fuzhou 350002, Fujian, China.
Dalton Trans. 2018 Oct 30;47(42):14938-14944. doi: 10.1039/c8dt03012j.
Hydrotalcite-like compounds (HTlcs) are promising supports or catalyst precursors for heterogeneous catalysts. Herein, MgAl-HTlcs-supported Pd catalyst was fabricated, and two Pd catalysts supported on Mg(OH)2 and Al(OH)3 were prepared for comparison. The presence of hydroxyl groups (OH-) in the support is important for obtaining uniform Pd nanoparticles with small sizes. We found that Pdn+ species are more active than Pd0 in low temperature CO oxidation due to their lower barrier in CO activation. The Pd/MgAl-HT catalyst shows the most stable Pdn+ at a temperature lower than 90 °C, leading to the highest catalytic activity towards CO oxidation. Pdn+ in the Pd/Al(OH)3 catalyst is more stable than that in Pd/Mg(OH)2 at low temperature, which is ascribed to its smaller temperature hysteresis (Thysteresis) between the oxidation and re-reduction cycles. The effect of hydroxyl groups on stabilizing Pd species is related to the stability of Pd catalyst in CO oxidation reaction.
水滑石类似物（HTlcs）是一种很有前途的多相催化剂载体或前体催化剂。本文制备了 MgAl-HTlcs 负载的 Pd 催化剂，并制备了负载在 Mg(OH)2 和 Al(OH)3 上的两种 Pd 催化剂进行比较。载体中存在羟基（OH-）对于获得具有小尺寸的均匀 Pd 纳米粒子非常重要。我们发现，由于 CO 活化的势垒较低，Pdn+ 物种比 Pd0 在低温 CO 氧化中更具活性。Pd/MgAl-HT 催化剂在低于 90°C 的温度下表现出最稳定的 Pdn+，从而对 CO 氧化表现出最高的催化活性。在低温下，Pd/Al(OH)3 催化剂中 Pdn+ 的稳定性高于 Pd/Mg(OH)2，这归因于其在氧化和再还原循环之间较小的温度滞后（Thysteresis）。羟基对稳定 Pd 物种的影响与 CO 氧化反应中 Pd 催化剂的稳定性有关。
