Palladium nanoparticles (Pd NPs) have been drawing great interest as catalysts for water treatment. Herein, high molecular weight polyethyleneimine (PEI) (molecular weight: 70 kDa) was used as template to stabilize Pd NPs. PEI was incubated with disodium tetrachloropalladate, followed by reduction with sodium borohydride. Pd NPs had narrow size distribution with diameter from 3.64 to 6.20 nm. The PEI-stabilized palladium nanoparticles (Pdn-PEI NPs) showed excellent long-term stability and positive zeta potential in phosphate saline buffers with different pH values. In addition, Pdn-PEI NPs exhibited high efficiency for catalysis of 4-nitrophenol (4-NP) in aqueous solution. The catalytic reduction of 4-NP followed the pseudo-first-order behavior, which had the highest catalytic ability (knor = 229). The enhanced properties can be attributed to the high stability and smaller size of Pdn-PEI NPs in aqueous solution, resulting from the application of PEI template. This method can be used to prepare highly stable metal nanoparticles with potential applications in catalysis of polluted water in the future.Graphical abstract

中文翻译：

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聚乙烯亚胺稳定的钯纳米颗粒用于还原 4-硝基苯酚

钯纳米颗粒（Pd NPs）作为水处理催化剂引起了人们的极大兴趣。在此，高分子量聚乙烯亚胺 (PEI)（分子量：70 kDa）用作模板来稳定 Pd NP。PEI 与四氯钯酸二钠一起孵育，然后用硼氢化钠还原。Pd NPs 的粒径分布较窄，直径为 3.64 至 6.20 nm。PEI 稳定的钯纳米粒子 (Pdn-PEI NPs) 在不同 pH 值的磷酸盐盐水缓冲液中显示出优异的长期稳定性和正 zeta 电位。此外，Pdn-PEI NPs 对水溶液中 4-硝基苯酚 (4-NP) 的催化效率很高。4-NP的催化还原遵循准一级行为，具有最高的催化能力（knor = 229）。增强的性能可归因于 PEI 模板的应用导致 Pdn-PEI NPs 在水溶液中的高稳定性和较小的尺寸。该方法可用于制备高度稳定的金属纳米粒子，未来在污水催化方面具有潜在应用。