Fundamental studies on the synthesis of supported metal nanoparticles: steric hindrance and coordination effects of anionic stabilizers

Abstract

The application of anionic stabilizers is of great importance in the synthesis of supported metal nanoparticles with small and uniform size and high dispersion. Herein, we extensively studied the influence of four congeneric anionic stabilizers on the morphology of carbon-supported Pd nanoparticles, and evaluated the efficacy of anionic stabilizers by testing the catalytic property of supported Pd nanoparticles toward formic acid electrooxidation. The results reveal that the morphology of carbon-supported Pd nanoparticles strongly depends on the steric hindrance and coordination effects of the anionic stabilizers. To be more specific, (1) large steric hindrance of anionic stabilizers is beneficial to form a small and uniform Pd particle size; (2) coordination compound formation between Pd ions and stabilizer molecules facilitates the dispersion of Pd nanoparticles on carbon black; and (3) both large steric hindrance and coordination compound formation can decrease the deposition of Pd nanoparticles in the micropores of carbon black. This work provides a reference point for future work aspiring to develop even better anionic stabilizers for the synthesis of supported metal nanoparticles.