title: Barrierless growth of precursor-free, ultrafast laser-fragmented noble metal nanoparticles by colloidal atom clusters - A kinetic in situ study.
abstract: Unintended post-synthesis growth of noble metal colloids caused by excess amounts of reactants or highly reactive atom clusters represents a fundamental problem in colloidal chemistry, affecting product stability or purity. Hence, quantified kinetics could allow defining nanoparticle size determination in dependence of the time. Here, we investigate in situ the growth kinetics of ps pulsed laser-fragmented platinum nanoparticles in presence of naked atom clusters in water without any influence of reducing agents or surfactants. The nanoparticle growth is investigated for platinum covering a time scale of minutes to 50days after nanoparticle generation, it is also supplemented by results obtained from gold and palladium. Since a minimum atom cluster concentration is exceeded, a significant growth is determined by time resolved UV/Vis spectroscopy, analytical disc centrifugation, zeta potential measurement and transmission electron microscopy. We suggest a decrease of atom cluster concentration over time, since nanoparticles grow at the expense of atom clusters. The growth mechanism during early phase (<1day) of laser-synthesized colloid is kinetically modeled by rapid barrierless coalescence. The prolonged slow nanoparticle growth is kinetically modeled by a combination of coalescence and Lifshitz-Slyozov-Wagner kinetic for Ostwald ripening, validated experimentally by the temperature dependence of Pt nanoparticle size and growth quenching by Iodide anions.
authors.affiliation: Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 7, 45141 Essen, Germany. Electronic address: sandra.jendrzej@uni-due.de.
authors.forename: Sandra
authors.initials: S
authors.lastname: Jendrzej
authors.affiliation: Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 7, 45141 Essen, Germany. Electronic address: bilal.goekce@uni-due.de.
authors.forename: Bilal
authors.initials: B
authors.lastname: Gökce
authors.affiliation: Department of Chemical Sciences, Università di Padova, 1 Via Marzolo, I-35131 Padova, Italy. Electronic address: vincenzo.amendola@unipd.it.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Amendola
authors.affiliation: Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitaetsstr. 7, 45141 Essen, Germany. Electronic address: stephan.barcikowski@uni-due.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Barcikowski
mesh_terms: D000838:Anions / Q000737:chemistry; D003102:Colloids / Q000737:chemistry; D007454:Iodides / Q000737:chemistry*; D007700:Kinetics; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D010316:Particle Size; D010984:Platinum / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000838:Anions; D003102:Colloids; D007454:Iodides; D010984:Platinum; D010165:Palladium
keywords: Coalescence; Growth kinetics; Laser-generated nanoparticles; Metal atom clusters; Mie theory; Ostwald ripening; Particle growth; Pulsed laser ablation; Pulsed laser fragmentation; Time resolved spectroscopy