Mahanitipong Usana, Tummachote Jakkrit, Thoopbucha Wachirawit, Inthanusorn Wasawat, Rutnakornpituk Metha
Department of Chemistry and Center of Excellence in Biomaterials, Faculty of Science, Naresuan University, Phitsanulok, 65000, Thailand.
Discov Nano. 2023 Nov 2;18(1):138. doi: 10.1186/s11671-023-03918-1.
This study focuses on the synthesis of magnetite nanoparticles (MNP) coated with poly(poly(ethylene glycol) methacrylate) (PPEGMA) and/or poly(acrylic acid) (PAA) to anchor palladium nanoparticles (Pd) for their application as recyclable catalysts in the reduction of 4-nitrophenol (4NP). It was hypothesized that the abundance of oxygen atoms in PPEGMA enabled coordination with the Pd and provided good water dispersibility of the nanocomposites, while anionic PAA stabilized Pd and reduced the catalyst aggregation through electrostatic repulsion. Three different polymer coatings on MNP (PAA, PPEGMA, and PAA-co-PPEGMA polymers) were investigated to assess their influence on both the catalytic activity and reusability of the catalysts. Transmission electron microscopy (TEM) analysis indicated the distribution of spherical Pd nanoparticles (3-5 nm in diameter) and MNP (9-12 nm in diameter). Photocorrelation spectroscopy (PCS) revealed an average hydrodynamic size of the catalysts ranging from 540 to 875 nm in diameter, with a negative charge on their surface. The Pd content of the catalysts ranged from 4.30 to 6.33% w/w. The nanocomposites coated with PAA-co-PPEGMA polymers exhibited more favorable catalytic activity in the 4NP reduction than those coated with PAA or PPEGMA homopolymers. Interestingly, those containing PAA (e.g., PAA and PAA-co-PPEGMA polymers) exhibited good reusability for the 4NP reduction with a slight decrease in their catalytic performance after 26 cycles. This indicates the important role of carboxyl groups in PAA in maintaining high tolerance after multiple uses.
本研究聚焦于合成包覆有聚（聚乙二醇甲基丙烯酸酯）（PPEGMA）和/或聚丙烯酸（PAA）的磁铁矿纳米颗粒（MNP），以锚定钯纳米颗粒（Pd），将其用作4-硝基苯酚（4NP）还原反应中的可回收催化剂。据推测，PPEGMA中丰富的氧原子能够与Pd配位，并使纳米复合材料具有良好的水分散性，而阴离子型PAA则使Pd稳定，并通过静电排斥作用减少催化剂的聚集。研究了MNP上的三种不同聚合物涂层（PAA、PPEGMA和PAA-co-PPEGMA聚合物），以评估它们对催化剂催化活性和可重复使用性的影响。透射电子显微镜（TEM）分析表明，球形钯纳米颗粒（直径3-5nm）和MNP（直径9-12nm）分布其中。光散射光谱（PCS）显示，催化剂的平均流体动力学直径在540至875nm之间，其表面带负电荷。催化剂的Pd含量在4.30至6.33% w/w之间。包覆有PAA-co-PPEGMA聚合物的纳米复合材料在4NP还原反应中表现出比包覆有PAA或PPEGMA均聚物的纳米复合材料更有利的催化活性。有趣的是，含有PAA的那些（如PAA和PAA-co-PPEGMA聚合物）在4NP还原反应中表现出良好的可重复使用性，在26次循环后其催化性能略有下降。这表明PAA中的羧基在多次使用后保持高耐受性方面发挥了重要作用。
