在4H晶相Au纳米带上外延生长非常规晶相4H-Pd基合金纳米结构用于高效甲醇电催化氧化

Epitaxial Growth of Unconventional 4H-Pd Based Alloy Nanostructures on 4H-Au Nanoribbons towards Highly Efficient Electrocatalytic Methanol Oxidation

Pd基合金纳米材料通常具有传统的面心立方(fcc)晶相。本文以密排六方4H相Au(4H-Au)纳米带为模板,外延生长非常规4H晶相的PdFe、PdIr和PdRu,形成4H-Au@PdM(M=Fe、Ir和Ru)核壳合金纳米带。合成的4H-Au@PdFe纳米带被用于碱性环境中甲醇电催化氧化反应(MOR)的催化剂,表现出优越的质量活性(3.69 A·mgPd^(−1)),分别为Pt/C和Pd黑催化剂质量活性的2.4和10.5倍,也跻身于最好的Pd基和Pt基MOR电催化剂之列。这一策略为合理设计和可控合成具有非常规晶相的多金属纳米结构提供了策略,从而为深入研究多金属纳米结构晶相依赖的性质和应用提供了可能。

Direct methanol fuel cells(DMFCs)hold great promise as clean energy conversion devices in the future.Noble metal nanocatalysts,renowned for their exceptional catalytic activity and stability,play a crucial role in DMFCs.Among these catalysts,Pt-and Pd-based nanocatalysts are widely recognized as the most effective catalysts for the electrochemical methanol oxidation reaction(MOR),which is the key half-cell reaction in DMFCs.However,due to the high cost of Pt-and Pd-based materials,there is a strong desire to further enhance their catalytic performance.One of the most promising approaches for it is to develop noble metal-based alloy nanocatalysts,which have shown great potential in improving electrocatalytic activity.Notably,advancements in phase engineering of nanomaterials(PEN)have revealed that noble metal-based nanomaterials with unconventional phases exhibit superior catalytic properties in various catalytic reactions compared to their counterparts with conventional phases.To obtain noble metal-based nanocatalysts with unconventional crystal phases,wet-chemical epitaxial growth has been employed as a facile and effective method,utilizing unconventional-phase noble metal nanocrystals as templates.Nevertheless,epitaxially growing bimetallic alloy nanostructures with unconventional crystal phases remains a challenge,impeding further exploration of their catalytic performance in electrochemical reactions such as MOR.In this study,we utilize 4H hexagonal phase Au(4H-Au)nanoribbons as templates for the epitaxial growth of unconventional 4H hexagonal PdFe,PdIr,and PdRu,resulting in the formation of 4H-Au@PdM(M=Fe,Ir,and Ru)core-shell nanoribbons.As a proof-of-concept application,we investigate the electrocatalytic activity of the synthesized 4H-Au@PdFe nanoribbons towards MOR,which exhibit a mass activity of 3.69 A·mgPd^(−1),i.e.,10.5 and 2.4 times that of Pd black and Pt/C,respectively,placing it among the best Pd-and Pt-based MOR electrocatalysts.Our strategy opens up an avenue for the rational construction of unconventional-phase multimetallic nanostructures to explore their phase-dependent properties in various applications.