Pt3Mn alloy nanostructure with high-index facets by Sn doping modified for highly catalytic active electro-oxidation reactions

Abstract

Modulating the surface structure of Pt-based alloy by oxyphilic component has been proven significantly enhancement of activity and stability for electro-oxidation of small organic molecules. Inspired by these advances, the oxyphilic metal Sn is implanted into the surface of Pt3Mn concave nanocubes (CNCs) to explore the promoting effect of foreign component on stepped Pt based alloy surface in this work. Detailed characterizations of catalysts reveal that the significant surface alloying layers (Pt-Mn-Sn) are formed after the insertion of Sn. The obtained Sn/Pt3Mn catalysts present the better specific activity (SA) and mass activity (MA) compared to the unmodified Pt3Mn catalyst towards both the electro-oxidation of formic acid (FAOR) and methanol (MOR). The optimal 0.5%Sn/Pt3Mn exhibits the enhanced mass activity of 4.07 and 2.60 folds than the Pt3Mn CNCs for MOR and FAOR, respectively. In particular, the optimal 0.5%Sn/Pt3Mn catalyst performs the efficient boost of stability and CO tolerance ability due to the stabilized effect on surface structure by Sn. Further investigations indicate that the presence of oxyphilic metal Sn can efficiently protect the surface structure from disruption. The thermodynamics studies also suggest that the Sn-doped catalysts have the advantage in decreasing the reaction activation energy than that of uncorporated Sn. All results demonstrate that the doped-Sn oxyphilic metals on the surface of Pt3Mn CNCs with high-index facets (HIFs) gives the better catalytic performance for electrooxidation of small organic molecules, further providing the design strategy for the protection of HIFs.