A hydride-induced-reduction strategy for fabricating palladium-based core–shell bimetallic nanocrystals

Abstract

One key challenge in making high-quality bimetallic nanocrystals is to prevent self-nucleation of individual metal components. We report in this work an effective seeded growth strategy that uses activated hydrogen atoms as the reducing agent to prepare core-shell bimetallic nanocrystals. In the developed method, Pd nanocrystals serve as the seed and catalyst as well to activate H2 for the reductive deposition of Ag. The unique feature of the developed method is that the activated hydrogen atoms are confined on the surface of the Pd seeds. Consequently, the self-nucleation of Ag is effectively inhibited so that the deposition of Ag occurs only on Pd. The mechanism studies reveal that reductive growth of Ag on Pd seeds proceeds until the Pd surface is fully covered by Ag. The Ag/Pd ratio in the prepared Pd@Ag nanocrystals is readily fine-tuned by the amount of AgNO3 or H2. The method is effective for depositing Ag on Pd nanocrystal seeds with different morphologies such as nanosheets, nanocubes, tetrahedra and nanowires. More importantly, the deposition of Ag on Pd nanowires allows preparation of flexible transparent electrode material with sheet electronic conductivity of 271 S sq(-1) at a transmittance of over 90%.

Seed-mediated growth of MOF-encapsulated Pd@Ag core–shell nanoparticles: toward advanced room temperature nanocatalysts

“…12 The highly active H atoms possessed a remarkably superior reducing ability as compared to H 2 to effectively reduce Ag + to metallic Ag, otherwise unachievable using molecular hydrogen at room temperature. 13 …”

Interfacial Effects in PdAg Bimetallic Nanosheets for Selective Dehydrogenation of Formic Acid

“…The plasmonic behaviors of PdAg BNSs were somewhat different from those of Pd@Ag core-shell structures reported previously. [29,30] Both XRD and UV/Vis characterizations suggested the possible presence of PdAg alloy in the PdAg BNSs prepared by reducing AgNO 3 on Pd NSs with sodium citrate at 70 8C. We argue that the use of sodium citrate is of great importance in obtaining the PdAg alloy BNSs, since citratei ons have strong coordinating ability with both Pd 2 + and Ag + .…”

Single‐Crystalline Rhodium Nanosheets with Atomic Thickness

“…Similar to metal nanoporous materials,32, 33, 34, 35 2D metal nanosheets exhibit high surface areas and thus high performance in catalysis. Many 2D metal nanosheets also display unit optical and electronic properties 12, 23, 27, 28, 29, 30…”