Component-controlled synthesis of Pd x Sn y nanocrystals on carbon nanotubes as advanced electrocatalysts for oxygen reduction reaction.

Pd-based bimetallic or multimetallic nanocrystals are considered to be potential electrocatalysts for cathodic oxygen reduction reaction (ORR) in fuel cells. Although much advance has been made, the synthesis of component-controlled Pd-Sn alloy nanocrystals or corresponding nanohybrids is still challenging, and the electrocatalytic ORR properties are not fully explored. Herein, component-controlled synthesis of Pd x Sn y nanocrystals (including Pd 3 Sn, Pd 2 Sn, Pd 3 Sn 2, and PdSn) has been realized, which are in situ grown or deposited on pre-treated multi-walled carbon nanotubes (CNTs) to form well-coupled nanohybrids (NHs) by a facile one-pot non-hydrolytic system thermolysis method. In alkaline media, all the resultant Pd x Sn y /CNTs NHs are effective at catalyzing ORR. Among them, the Pd 3 Sn/CNTs NHs exhibit the best catalytic activity with the half-wave potential of 0.85 V ( vs. RHE), good cyclic stability, and excellent methanol-tolerant capability due to the suited Pd-Sn alloy component and its strong interaction or efficient electronic coupling with CNTs. This work is conducive to the advancement of Pd-based nanoalloy catalysts by combining component engineering and a hybridization strategy and promoting their application in clean energy devices.