Heterogeneous Pd catalysts were developed by immobilizing Pd nanoparticles (Pd NPs) onto plant polyphenol (bayberry tannin, BT) decorated γ-Al2O3. The abundant hydroxyls of plant polyphenols were capable of stabilizing the Pd NPs. Transmission electron microscopy observation confirmed that the Pd NPs with the diameter of 3.75 ± 0.5 nm were highly dispersed in the catalyst. The as-prepared Al2O3–BT–Pd catalysts were found to be highly active in mild hydrodechlorination (HDC) of 2,4-dichlorophenols (DCPs) using formic acid as a hydrogen source. The 2,4-DCPs were completely dechlorinated in 4 h at 30°C and under atmospheric pressure. During the catalytic HDC, the stabilizing capability of BT successfully prevented the leakage and aggregation of Pd NPs, thus ensuring a high cycling stability with stable and high catalytic activity. The Al2O3–BT–Pd catalysts were recycled six times, without obvious loss of activity. In the sixth cycle, the catalytic HDC yield still reached 98.29% under the same reaction conditions, superior to the control catalysts, including γ-Al2O3 supported Pd NPs (Al2O3–Pd) and powdered activated carbon supported Pd NPs (AC–Pd). Furthermore, the Al2O3–BT–Pd also showed high activity in the mild catalytic HDC of 2,4,6-trichlorophenols and chlorobenzene derivatives. Our results demonstrated efficient catalysts to address the environmental issue of chlorophenol pollution.

中文翻译：

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负载在植物多酚改性γ-Al2O3上的可回收异质钯纳米颗粒用于2,4-二氯酚的加氢脱氯

通过将 Pd 纳米粒子 (Pd NPs) 固定在植物多酚 (杨梅单宁, BT) 装饰的 γ-Al2O3 上，开发了多相 Pd 催化剂。植物多酚的丰富羟基能够稳定 Pd NP。透射电子显微镜观察证实，直径为 3.75±0.5 nm 的 Pd NPs 高度分散在催化剂中。发现所制备的 Al2O3–BT–Pd 催化剂在使用甲酸作为氢源的 2,4-二氯苯酚 (DCP) 的温和加氢脱氯 (HDC) 中具有高活性。在 30°C 和大气压下，2,4-DCP 在 4 小时内完全脱氯。在催化 HDC 过程中，BT 的稳定能力成功地防止了 Pd NPs 的泄漏和聚集，从而确保了具有稳定和高催化活性的高循环稳定性。Al2O3-BT-Pd 催化剂循环使用 6 次，没有明显的活性损失。在第六个循环中，在相同反应条件下，催化 HDC 产率仍达到 98.29%，优于对照催化剂，包括 γ-Al2O3 负载的 Pd NPs（Al2O3-Pd）和粉末活性炭负载的 Pd NPs（AC-Pd）。此外，Al2O3-BT-Pd 在 2,4,6-三氯苯酚和氯苯衍生物的温和催化 HDC 中也显示出高活性。我们的结果证明了有效的催化剂可以解决氯苯酚污染的环境问题。包括 γ-Al2O3 负载的 Pd NPs (Al2O3-Pd) 和粉状活性炭负载的 Pd NPs (AC-Pd)。此外，Al2O3-BT-Pd 在 2,4,6-三氯苯酚和氯苯衍生物的温和催化 HDC 中也显示出高活性。我们的结果证明了有效的催化剂可以解决氯苯酚污染的环境问题。包括 γ-Al2O3 负载的 Pd NPs (Al2O3-Pd) 和粉状活性炭负载的 Pd NPs (AC-Pd)。此外，Al2O3-BT-Pd 在 2,4,6-三氯苯酚和氯苯衍生物的温和催化 HDC 中也显示出高活性。我们的结果证明了有效的催化剂可以解决氯苯酚污染的环境问题。