Hu Jun, Liu Yubiao
Department of Chemistry, the University of Akron, Akron, OH 44325-3601, USA.
Langmuir. 2005 Mar 15;21(6):2121-3. doi: 10.1021/la0471902.
Examination of the catalysts recovered in the N,N-dihexylcarbodiimide-palladium nanoparticle composite catalyzed Suzuki cross-coupling reactions revealed that the metal nanoparticles transformed gradually from spherical-shape to larger needle-shaped crystals. Two types of Ostwald ripening processes were observed. One involves rapid aggregation of the incipient nanoparticle catalyst (2-5 nm) into blackberry-like assemblies (100-200 nm), which is accompanied with the much slower dissolution of small crystals or amorphous nanoparticles and the formation of larger needle-shaped crystals. The observed structural changes provided new insights into the durability of the polymer nanoparticle composite catalyst.
对在N，N-二己基碳二亚胺-钯纳米颗粒复合催化的铃木交叉偶联反应中回收的催化剂进行检查发现，金属纳米颗粒逐渐从球形转变为更大的针状晶体。观察到两种奥斯特瓦尔德熟化过程。一种涉及初始纳米颗粒催化剂（2-5纳米）迅速聚集成黑莓状聚集体（100-200纳米），同时伴随着小晶体或无定形纳米颗粒的溶解速度慢得多，以及形成更大的针状晶体。观察到的结构变化为聚合物纳米颗粒复合催化剂的耐久性提供了新的见解。
