Improvement of electrocatalytic alcohol oxidation by tuning the phase structure of atomically ordered intermetallic Pd-Sn nanowire networks

Atomically ordered intermetallic compounds (OICs) have aroused remarkable interests for wide applications and are considered as very promising materials for electrocatalysis owing to the strict stoichiometry, well-defined atom binding environment, and the specific crystalline phase. However, the tunable synthesis of the intermetallics remains a giant challenge. Herein, this study reports the preparation of the Pd-Sn OICs composed of an interconnected nanowire network structure with adjustable molar ratios of elements Pd and Sn. The co-reduction of Pd(acac) 2 and SnCl 2 ·2H 2 O in ethylene glycol (EG) in the presence of sodium hypophosphite (NaH 2 PO 2 ) as the reducing agent affords OICs of three phases: hexagonal Pd 3 Sn 2 - P 6 3 / mmc , orthorhombic PdSn- Pnmb , and orthorhombic PdSn 2 - Aba 2. Also, the pure phase can convert to two mixed phases (Pd 3 Sn 2 /PdSn and PdSn/PdSn 2 ) by just altering the feed ratio. It is found that orthorhombic PdSn- Pnmb OIC has a large electrochemically active surface area (ECSA), excellent electrocatalytic performance (4857 mA mg Pd −1 ), and outstanding stability toward ethanol oxidation reaction (EOR), which could be attributed to its optimal electronic structure. These results demonstrate that the phase engineering of OICs with desired components is an excellent way for catalysts design.