Direct Dry Synthesis of Supported Bimetallic Catalysts: A Study on Comminution and Alloying of Metal Nanoparticles

Abstract

Ball milling is growing increasingly important as an alternative synthetic tool to prepare catalytic materials. It was recently observed that supported metal catalysts could be directly obtained upon ball milling from the coarse powders of metal and oxide support. Moreover, when two compatible metal sources are simultaneously subjected to the mechanochemical treatment, bimetallic nanoparticles are obtained. A systematic investigation was extended to different metals and supports to understand better the mechanisms involved in the comminution and alloying of metal nanoparticles. Based on this, a model describing the role of metalsupport interactions in the synthesis was developed. The findings will be helpful for the future rational design of supported metal catalysts via dry ball milling.

Facile Solid-State Synthesis of Supported PtNi and PtCo Bimetallic Nanoparticles for the Oxygen Reduction Reaction

“…However, given favorable mixing conditions, it has been observed that when hard and soft, brittle and plastic samples are processed together, the harder component can act as a grinding body toward the soft and plastic one, and thus subject it to activation by means of deformation, which will lead to the latter being smeared over the former . These processes probably are the phenomenological reason for the successful mechanochemically induced deposition of metal nanoparticles (soft) over oxide supports (hard), in addition to the intrinsic metal–support interactions. , At the same time, such a notion could explain why attempts to extend the method to the synthesis of carbon-supported metal nanoparticles had failed so far, at least when coarse metal powders (soft) were combined with a suitable carbon source (soft) under seemingly suitable conditions . Thus, in this study, metal acetylacetonate salts were selected as the metal precursors.…”

“…20 These processes probably are the phenomenological reason for the successful mechanochemically induced deposition of metal nanoparticles (soft) over oxide supports (hard), in addition to the intrinsic metal−support interactions. 17,19 At the same time, such a notion could explain why attempts to extend the method to the synthesis of carbon-supported metal nanoparticles had failed so far, at least when coarse metal powders (soft) were combined with a suitable carbon source (soft) under seemingly suitable conditions. 21 Thus, in this study, metal acetylacetonate salts were selected as the metal precursors.…”

“…It has already been noted that ball milling can be a critical synthetic step in the preparation of various nanocomposite materials, which were, in many cases, recognized to be superior to their conventionally synthesized counterparts due to the increased number of interparticle contacts and small particle sizes . In addition, the direct synthesis of supported metal catalysts (on oxide supports) simply from the combination of coarse powders by similar means suggests ball milling as a suitable method for the synthesis of fuel cell catalysts. − …”

Selective hydrogenation of highly concentrated acetylene streams over mechanochemically synthesized PdAg supported catalysts

“…29 The method proved to be somewhat flexible concerning the choice of metals and oxide support. 30 In fact, compatibly with the scope of the study, it was used to prepare a variety of supported PdAg catalysts with different relative content of Pd and Ag. The effect of composition on catalytic behavior was studied in detail.…”

Mechanochemical synthesis of a high-surface-area Pd/α-Al2O3 catalyst for CO oxidative coupling to dimethyl oxalate reaction

“…3,4 Various kinds of catalytic materials, including metal particles, supported metal and bimetallic catalysts, metal oxides, and metal-organic frameworks, have been synthesized by mechanochemistry. [5][6][7][8][9] The synthetic method endows the materials with a unique nature, such as an increase in the surface area, change of chemical composition, and alteration of the structure, which usually are impossible to achieve by traditional strategies. Recently, Amol P. Amrute et al synthesized nanometer-sized α-Al 2 O 3 with a surface area up to 140 m 2 g −1 by a mechanochemical method at room temperature.…”