Bimetallic Nickel‐Iridium and Nickel‐Osmium Alloy Nanoparticles and Their Catalytic Performance in Hydrogenation Reactions

Abstract

Bimetallic NiIr4 and NiOs4 alloy nanoparticles are prepared and studied with regard to their performance in catalytic hydrogenation reactions. NiIr4 and NiOs4 nanoparticles are obtained by oleylamine‐driven reduction and exhibit mean diameters of (8.9±1.3) and (6.8±1.4) nm at low agglomeration. The phase composition was determined in detail by using different methods, which include high‐resolution TEM, scanning transmission electron microscopy, selected‐area electron diffraction, X‐ray diffraction, and energy‐dispersive X‐ray spectroscopy. This and results in a uniform distribution of both metals Ni‐Ir and Ni‐Os with a ratio of 1:4. The catalytic performance of the NiIr4 and NiOs4 nanoparticles for hydrogenation reactions is evaluated using three selected model substrates: 1‐octene, cinnamaldehyde, and diphenylacetylene. Similar sized Ni, Ir, and Os nanoparticles were used as references. Most remarkable are the excellent selectivity of NiOs4 in the hydrogenation of cinnamaldehyde and the promising formation of (Z)‐stilbene in terms of conversion activity and selectivity. The alloying of Ir and Os with Ni, moreover, is highly cost efficient. In general, both bimetallic alloy nanoparticles, NiIr4 and NiOs4, are shown here for the first time in terms of synthesis, composition, and catalytic hydrogenation.

Bimetallic Synergy Effects of Phyllosilicate‐Derived NiCu@SiO2 Catalysts for 1,4‐Butynediol Direct Hydrogenation to 1,4‐Butanediol

“…[17] Besides, concerning on the structural feature of BYD which has various unsaturated bonds, the hydrogenation of BYD will not only include the C�C and C=C hydrogenation process, but also involved by many side reactions such as isomerization, aldol condensation and C=O hydrogenolysis because of the unsaturated feature of CÀ O bonds (CÀ OH or C=O). [22][23][24] In the ortho-elements of Ni, Cu has a similar inner electronic distribution with Ni, but with different outer electron cloud, which can form bimetallic synergistic effect with nickel and enhance the hydrogen overflow/transfer ability of the surrounding metal surface, [15] thus stabilizing the adsorption state of allyl alcohol form. [18][19][20] BYD is usually first semi-hydrogenated to form unsaturated BED, which can be then hydrogenated to BDO.…”

“…A simple way to boost the adsorption of C=C bond (electron clouds above the carbon chains) over BED is to modify the active metal site surface properties and surrounding electronic environment via second metal promoters. [22][23][24] In the ortho-elements of Ni, Cu has a similar inner electronic distribution with Ni, but with different outer electron cloud, which can form bimetallic synergistic effect with nickel and enhance the hydrogen overflow/transfer ability of the surrounding metal surface, [15] thus stabilizing the adsorption state of allyl alcohol form. [25] On the other hand, since the essence of isomerization of BED is the electron clouds shift from the CÀ OH to the CÀ C chains, [21] we may use some assistant sites to distract electron cloud density over terminal À OH group, thus retard its dominant isomerization pathway.…”

New Aspects of Platinum Group Metal‐Based Solid‐Solution Alloy Nanoparticles: Binary to High‐Entropy Alloys

“…Os and Os‐based alloy NPs have not been widely studied yet, and therefore it is hard to understand their properties. Some reports covering their combination with Ru, Re, or Ir were found in the survey, although those were mostly not about the Os‐based alloy NPs themselves, rather, in a few reports, Os‐based alloy NPs were studied for their catalytic properties for hydrogenation and oxidation reactions, even though they are categorized into class 2 or 5 alloy systems …”

Introductory Chapter: Overview of the Properties and Applications of Noble and Precious Metals

“…use of Ni-Ir and Ni-Os bimetallic NP alloys for hydrogenation reactions [48], Os NPs for CO oxidation [49,50], and Os NP electro-catalysts for PEM fuel cells [51] and direct methanol fuel cells [52].…”