Design and Validation of a Fluidized Bed Catalyst Reduction Reactor for the Synthesis of Well-Dispersed Nanoparticle Ensembles

Pt-based nanoparticles supported on carbon materials are state-of-the-art electrocatalysts for proton exchange membrane fuel cells (PEMFCs). Interparticle distance and particle size of the supported nanoparticles play a crucial role for the catalyst's performance. The synthesis approach of wet impregnation and thermal reduction in a regular static packed-bed tube furnace often results in poorly distributed Pt particles in terms of interparticle distance and particle size. Here, we report on a fluidized bed gas reduction reactor for the preparation of supported well-dispersed nanoparticles. To validate the reactor, we compared and contrasted Pt nanoparticle ensembles supported on Vulcan XC 72R prepared using a conventional, horizontal static packed bed tube furnace, and using our novel vertical fluidized bed reduction reactor. The catalysts were physico-chemically characterized and electrochemically tested with respect to their electrocatalytic oxygen reduction reaction reactivity using rotating disk electrode (RDE) experiments. Our results demonstrate that the nanoparticle samples prepared in the customized fluidized bed reduction reactor showed significantly superior mono-dispersion and more homogeneously spatial distribution that resulted in improved electrochemical stability.