Nanostructured Pt/C electrocatalysts with high platinum dispersions through zeolite-templating

A method for the preparation of size-controlled Pt clusters on nanostructured carbon is described. The carbon possesses tunable micro and mesoporosity, and forms an integrated matrix around the size-controlled Pt clusters. The process involves stabilization of Pt clusters in a zeolite host, pore-filling of the host with a carbon precursor, pyrolysis and removal of the host. The properties of the catalysts vary over a wide range depending on the precise synthesis conditions. On one end of the spectrum, Pt clusters as small as 1.3 nm (average), with narrow size distribution in intimate contact with a predominantly microporous carbon network are obtained; on the other end, Pt clusters of average size 1.7 nm were obtained within a hybrid microporous/mesoporous carbon matrix. Low-angle X-ray diffraction shows periodic nanostructuring (d ∼ 1.4 nm) for Pt/C with Pt loadings ⩽17 wt.%, which is confirmed by TEM imaging. Electrochemical evaluation showed these catalysts to have high electro-active surface areas, and to be at least as active as a commercial Pt/C in the reduction of oxygen.