Synthesis of Low Pt-Based Quaternary PtPdRuTe Nanotubes with Optimized Incorporation of Pd for Enhanced Electrocatalytic Activity

Improving heteroatomic interactions via alloying or forming heterogeneous catalysts is of importance to the enhancement in terms of electrocatalytic activity and stability. In this work, a simple galvanic replacement reaction was utilized to synthesize low Pt-based quaternary nanotubes (NTs). It is easy to obtain PtPdRuTe NTs with different composition and controlled shape using ultrathin Te nanowires (NWs) as sacrificial templates for its high activity. The NT wall thickness and formed NPs on the surface are closely related with the composition, especially Pd content. The optimized incorporation of Pd atoms into ternary PtRuTe NTs formed a uniform protecting PtPd surface and modified the Pt electronic structure to improve the methanol oxidation reaction (MOR) performance. X-ray photoelectron spectroscopy (XPS) reveals a larger extent of electron transfer from neighboring atoms to Pt on PtPdRuTe, consequently leading to a weaker bonding of the intermediate on Pt. As a result, the quaternary PtPdRuTe NTs exhibit enhanced activity and stability toward efficient MOR

Scalable Bromide-Triggered Synthesis of Pd@Pt Core–Shell Ultrathin Nanowires with Enhanced Electrocatalytic Performance toward Oxygen Reduction Reaction

This article reports a novel scalable method to prepare ultrathin and uniform Pd@Pt nanowires (NWs) with controllable composition and shell thickness, high aspect ratio, and smooth surface, triggered by bromide ions via a galvanic replacement reaction between PtCl₆^2– and Pd NWs. It was found that bromide ions played a vital role in initiating and promoting the galvanic reaction. The bromide ions served as capping and oxidized etching agents, counterbalancing the Pt deposition and Pd etching on the surface to give final Pd@Pt core–shell nanostructures. Such a counterbalance and the formation PtBr₆^2– with lower redox potential could lower the reaction rate and be responsible for full coverage of a smooth Pt shell. The full coverage of Pt deposited on Pd NWs is important for the enhancement of the activity and stability, which depend strongly on the Pt content and Pt shell thickness. Significantly, the Pd@Pt NWs with Pt content of 21.2% (atomic ratio) exhibited the highest mass activity (810 mA mg^–1_Pt) and specific activity (0.4 mA cm^–2). Interestingly, the mass activity (1560 mA mg^–1_Pt) and specific activity (0.98 mA cm^–2) of Pd@Pt (21.2%) NWs increased to 2.45 and 1.95 times the initial values after 60k cycles tests, 8.5 and 9.0 times greater than those of Pt/C catalysts. In addition, these ultrathin NW electrocatalysts with large aspect ratio are easy to form into a freestanding film, which improves the mass transport, electrical conductivity, and structure stability