Crystal structure engineering in metallic nanoparticles represents an important strategy in catalyst design, as the composition, shape, exposed facets, crystal structure, and atom distribution dictate activity. While techniques have been developed to control each of these parameters, there is no general method that allows one to optimize all parameters in polyelemental systems. In this work we combine a solid-state, Bi-influenced, high-index facet shape regulation strategy with thermal annealing, to achieve control over crystal structure in high-index facet nanoparticles. Indeed, this results in an unprecedentedly diverse library of chemically disordered and ordered multimetallic (Pt, Co, Ni, Cu, Fe, and Mn) tetrahexahedral (THH) nanoparticles. By employing density functional theory calculations we show that surface Bi modification stabilizes the {210} high-index facets of the nanoparticles, regardless of their internal atomic ordering. Moreover, we find that the ordering transition temperatures for the nanoparticles are dependent on their composition, which can be seen in the case of Pt3Fe1 THH nanoparticles. Finally, we have discovered that ordered intermetallic THH Pt1Co1 nanocatalysts exhibit a catalytic performance superior to disordered THH Pt1Co1 nanoparticles and commercial Pt/C catalysts toward methanol electrooxidation, highlighting the importance of crystal structure and atom distribution control on high-index facets in nanoscale catalysts. This approach broadens the synthetic scope and accessibility of new nanocatalysts for use in a diverse range of chemical processes.-

Crystal structure engineering in multimetallic high-index facet nanocatalysts

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