Kinetic diffusion-controlled synthesis of twinned intermetallic nanocrystals for CO-resistant catalysis.

Abstract

Intermetallic catalysts are of immense interest, but how heterometals diffuse and related interface structure remain unclear when there exists a strong metal-support interaction. Here, we developed a kinetic diffusion–controlled method and synthesized intermetallic Pt2Mo nanocrystals with twin boundaries on mesoporous carbon (Pt2Mo/C). The formation of small-sized twinned intermetallic nanocrystals is associated with the strong Mo-C interaction–induced slow Mo diffusion and the heterogeneity of alloying, which is revealed by an in situ aberration-corrected transmission electron microscope (TEM) at high temperature. The twinned Pt2Mo/C constitutes a promising CO-resistant catalyst for highly selective hydrogenation of nitroarenes. Theoretical calculations and environmental TEM suggest that the weakened CO adsorption over Pt sites of Pt2Mo twin boundaries and their local region endows them with high CO resistance, selectivity, and reusability. The present strategy paves the way for tailoring the interface structure of high–melting point Mo/W-based intermetallic nanocrystals that proved to be important for the industrially viable reactions.