Fibrous Silver Particles Prepared from Layered Silver Alkanethiolates and Their Catalytic Property

We have prepared fibrous silver particles (FSPs) by reducing layered silver alkanethiolates (LSTs) having various alkyl chain length. According to powder X-ray diffraction and infrared spectra, LSTs had lamellar structure with different interlayer distance with respect to alkyl chain length. Microscopic study revealed that LSTs particles had flat shape with hundreds of nanometers diameter and tens of nanometers thickness, regardless of alkyl chain length. Upon reductive calcination at 400 degrees C under H-2 flow, LSTs transformed to face centered cubic Ag fiber having bundle of Ag filaments having similar to 1 mu m diameter. Through Scherrer's equation, microscopic analyses and N-2 adsorption-desorption isotherm, it was revealed that silver nanoparticle preferentially aggregated to one direction during reduction to form FSPs, and molecules could access through the inter-particle space in the aggregates. Conversion of 4-nitrophenol to 4-aminophenol catalyzed by FSPs was analyzed with Langmuir-Hinshelwood model. It was found that FSPs had similar or higher catalytic reaction rate compared with Ag nanoparticles. Furthermore, FSPs were found to possess high recyclability by showing continuous catalytic activity after 5 catalytic reactions.