Au/C catalyst: Experimental evidence of the coexistence of nanoclusters and larger Au particles

In this study, using X-ray diffraction Rietveld analysis, we have determined that a great quantity of very fine particles (< 2 nm) can be present in a supported metal catalyst, but that they are almost undetectable if larger particles (even a very small fraction) are contained in the sample. The large amount of hidden fine particles found in the discussed catalyst convinced us that, probably, such a nanostructure could be characteristic of catalysts containing a low percentage of metal. Since heterogeneous catalysis is a surface phenomenon, it is clear that losing great fractions of nanoparticles biases the microstructural study, and hence, the understanding of the catalytic working mechanism.