Effects of Metal Composition and Ratio on Peptide-Templated Multimetallic PdPt Nanomaterials

Abstract

It can be difficult to simultaneously control the size, composition, and morphology of metal nanomaterials under benign aqueous conditions. For this, bioinspired approaches have become increasingly popular due to their ability to stabilize a wide array of metal catalysts under ambient conditions. In this regard, we used the R5 peptide as a three-dimensional template for formation of PdPt bimetallic nanomaterials. Monometallic Pd and Pt nanomaterials have been shown to be highly reactive toward a variety of catalytic processes, but by forming bimetallic species, increased catalytic activity may be realized. The optimal metal-to-metal ratio was determined by varying the Pd:Pt ratio to obtain the largest increase in catalytic activity. To better understand the morphology and the local atomic structure of the materials, the bimetallic PdPt nanomaterials were extensively studied by transmission electron microscopy, extended X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, and pair distribution function analysis. The resulting PdPt materials were determined to form multicomponent nanostructures where the Pt component demonstrated varying degrees of oxidation based upon the Pd:Pt ratio. To test the catalytic reactivity of the materials, olefin hydrogenation was conducted, which indicated a slight catalytic enhancement for the multicomponent materials. These results suggest a strong correlation between the metal ratio and the stabilizing biotemplate in controlling the final materials morphology, composition, and the interactions between the two metal species.

Mixed‐Metal MOF‐74 Templated Catalysts for Efficient Carbon Dioxide Capture and Methanation

“…The ratio of NiNi and NiMg within the local Ni coordination environment is consistent with ICP–OES results (Figure S1 and Table S1, Supporting Information), suggesting the Ni and Mg species are randomly distributed throughout the framework as seen elsewhere, rather than regions of discrete Ni‐MOF‐74 and Mg‐MOF‐74. [ 21 ] The NiC backscattering contribution is slightly overrepresented when compared with the theoretical structure which could be due to the similarity in interatomic distances between NiO and NiC. The neat MOF EXAFS modeling fits (Figures S27–S31, Supporting Information) along with the resulting fitting parameters (Table S9, Supporting Information).…”

“…To correct for this, we used the results from our LCF of the Ni XANES to calculate an effective NiNi CN that provides insights into the size of the Ni nanoparticles, as the percentage of oxidized Ni is directly quantifiable. [ 21 ] The resulting effective NiNi CNs are shown in Figure 6b as 5.8 ± 1.1, 4.0 ± 0.4, 9.7 ± 0.8, 5.9 ± 1.0, and 5.4 ± 0.8 for 20Ni80Mg, 40Ni60Mg, 60Ni40Mg, 80Ni20Mg, and 100Ni, respectively.…”

New Strategy for High-Performance Integrated Catalysts for Cracking Hydrocarbon Fuels

“…This phenomenon indicates that Pd 2+ is complexed with amines inside CPAMAM, and the hydrophilic core of CPAMAM can be brought into contact with the aqueous phase to promote the reduction reaction. Furthermore, the UV spectrum of the product Pd@CPAMAM shows a broadband absorption between 290 and 700 nm, corresponding to the formation of NPs. − …”

Multimetallic Nanoparticles as Alternative Antimicrobial Agents: Challenges and Perspectives

“…Trimetallic NPs exhibit improved reactivity because of the electronic and synergistic effects of the different elements and the geometric arrangements of the metal surrounding the absorbing atoms. At this coherence, the properties of the materials are altered due to electron transfer effects, lattice mismatching, and surface rearrangement [64]. Consequently, trimetallic NPs, such as Fe/Co/Ni supported on multiwalled carbon nanotubes (MWCNTs), show efficient and enhanced bifunctional performance for the oxygen reduction and oxygen evolution reactions [65].…”