【摘要】 原子有序的金属间化合物因其严格的化学计量与原子结合环境及特定的结晶相引起了人们的研究兴趣,并被认为是一类非常有前景的电催化材料.然而,金属间化合物纳米结构的可控合成仍面临挑战.本文研究了晶相可调Pd-Sn金属间化合物纳米线组成的网状结构的制备,即在乙二醇溶液中以次磷酸二氢钠为还原剂将乙酰丙酮钯和二水合氯化亚锡共还原,得到三种金属间化合物纳米线网状结构:六方晶系的Pd₃Sn₂-P63/mmc,正交晶系的PdSn-Pnmb和正交晶系的PdSn₂-Aba₂.改变投料比可实现由单相到混合两相的转换.研究发现, PdSn-Pnmb具有较大的电化学活性比表面积、优异的电催化活性(4857 mA mg^-1Pd)以及对乙醇电氧化反应显著的稳定性,这归因于其最优的电子结构.结果表明,理想组分的金属间化合物的相工程调控是催化剂设计的一种有效途径.更多还原

【Abstract】 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 SnCl₂·2 H₂ O in ethylene glycol（EG） in the presence of sodium hypophosphite（NaH₂ PO₂） as the reducing agent affords OICs of three phases:hexagonal Pd₃ Sn₂-P63/mmc, orthorhombic PdSn-Pnmb, and orthorhombic PdSn₂-Aba₂. Also, the pure phase can convert to two mixed phases（Pd₃ Sn₂/PdSn and PdSn/PdSn₂） by just altering the feed ratio. It is found that orthorhombic PdSnPnmb OIC has a large electrochemically active surface area（ECSA）, excellent electrocatalytic performance(4857 mA mg^-1 Pd), 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.更多还原