Synthesis and application of palladium stearates as precursors for the preparation of palladium nanoparticles

Abstract

This report successfully demonstrates the synthesis and application of palladium stearates. It was found that the branching of the carboxylate anion of metal precursors could influence the size and shape of palladium nanoparticles (PdNPs). Worm-like nanowires were formed when using the branched isomer palladium isostearate (PdISt 2 ), while triangular nanoparticles were produced in a majority when using the normal form: palladium stearate (PdSt 2 ). Furthermore, when applying CO 2 to the system, both types of PdNPs transformed into more spherical shapes with smaller sizes. The formation of carbamates from the amine stabilizer with CO 2 could prevent the further growth and aggregation of PdNPs. The PdNPs were tested as catalysts for the hydrogenation of styrene, and higher catalytic activities were achieved with PdNPs that were prepared with the assistance of CO 2 .

Shape‐directed platinum nanoparticle synthesis: nanoscale design of novel catalysts

“…The control of shape and size during platinum nanoparticle synthesis is an essential part of designing and studying catalyst materials with improved activity and selectivity. Recent studies which characterized catalysts' shapes and exposed surfaces indicate that surface structures can be altered to tune catalytic properties . It was also shown that high index facets on a catalyst surface may exhibit higher activities than lower index facets for certain reactions due to the decreased coordination of step edges and defects, but these sites can also be detrimental to other reactions .…”

“…WCR has become one of the most common catalyst preparation methods due to the vastly controllable synthetic parameters . Early reports of this method go as far back as 1857 and can be used in systems of gold, palladium, cobalt and silver . Some of the earliest reports of Pt shape direction using WCR were reported in 1941 by Rampino and Nord and then later by El‐Sayed in 1996, but modifications and variations of these syntheses are still being developed today to design catalyst materials with enhanced properties.…”

Synthesis of highly monodisperse Pd nanoparticles using a binary surfactant combination and sodium oleate as a reductant

“…Among the different stabilizers employed in metal NP synthesis, fatty acids have been widely applied because of their high affinity to metals. In the synthesis of various metal NPs typical examples include lauric acid [17][18][19][20] , palmitic acid 17,21 , and stearic acid 17,22,23 . The most frequently applied fatty acid capping agent in metal NP synthesis is the unsaturated fatty acid oleic acid (OA), and its sodium salt form, sodium oleate (NaOL).…”