Synthesis, Structure, and Properties of C60-Pd Spherical Nanoparticles

Abstract

Synthesis, structure, and properties of C60-Pd spherical nanoparticles Krzysztof Winkler, Emilia Gradzka, Ewa Brancewicz Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok, Poland The C60-Pd polymer can be synthesized electrochemically1 or chemically.2 The electrochemical synthesis results in the formation of thin and uniform film on the electrode surface. The film is electrochemically active at negative potentials due to the fullerene cages reduction.1 The chemical synthesis of C60-Pd polymer, carried out in benzene solution containing Pd2(dba)3·CHCl3 and fullerene C60, results in formation of large crystalline superficial structures which are composed of a small spherical particles 20-200 nm in diameter (Fig. 1). These cubic semi-crystals can be disintegrated to spherical nanoparticles with the high energy ultrasound. The size of synthesized C60-Pd nanoparticles can be controlled by composition of grown solution, time of polymerization, temperature of synthesis, and stirring conditions. The most uniform in size particles were synthesized in solution containing 3:1 ratio of [Pd] to [C60] concentration. Dispersed C60-Pd nanoparticles are stable in many organic protic and aprotic solvents. The electrochemical properties of films formed from chemically synthesized nanoparticles were investigated. Special attention was paid to capacitance properties. The electrochemical behavior of these films resembles the one observed for electrochemically synthesized polymers. Capacitance properties of films formed from C60-Pd nanoparticles depend on the size of polymeric nanoparticles. The specific capacitance of polymer formed in solution containing 1:1 ratio of [Pd] to [C60] reaches the value obtained earlier for electrochemically synthesized material. The electrochemical properties of colloidal solutions of C60-Pd nanoparticles were also studied using ultramicroelectrodes. Diffusion controlled voltammograms are recorded for these systems. Two component nanoparticlec composed of C60-Pd core and polypyrrole shell were synthesized. The electrochemical properties of such p-nspherical nanojunction were studied both in solid phase and in the solution. Fig. 1. SEM (left panels) and TEM (right panels) images of chemically synthesized C60-Pd in benzene solution containing 0.48 mM C60 and 0.73 mM Pd2(dba)3·CHCl3 1. A.L. Balch, D.A.Costa, K. Winkler, J. Am. Chem. Soc., 120, 9614 (1998).2. H. Nagashima, A. Nakaoka, Y. Saito, M. Kato, T. Kawanishi, K. Lotha, J. Chem. Soc. Chem. Commun., 377-379 (1992).