From Small Metal Clusters to Molecular Nanoarchitectures with a Core–Shell Structure: The Synthesis, Redox Fingerprint, Theoretical Analysis, and Solid-State Structure of [Co₃₈As₁₂(CO)₅₀]^4–

Abstract

The cluster [Co 38 As 12 (CO) 50 ] 4− was obtained by pyrolysis of [Co 6 As(CO) 16 ] − . The metal cage features a closedpacked core inside a Co/As shell that progressively deforms from a cubic face-centered symmetry. The redox and acid−base reactivities were determined by cyclic voltammetry and spectrophotometric titrations. The calculated electron density revealed the shell-constrained distribution of the atomic charges, induced by the presence of arsenic.

Evaluation of Novel Fuel Cell Catalysts with Ultra-Low Noble Metal Contents towards Electrochemical Catalysis

“…[23][24][25]28 For ORR, alloys, core-shell structures and cage structures have recently been created and explored. [1][2][3][4][5] Pt-based bimetallic electrocatalysts.-Pure Pt NPs used to be the most cutting-edge materials for fuel cell cathodes and anodes, but they are no longer since they are too costly and do not give enough catalytic efficiency under real-world loads. When Pt is employed in isolation as a catalyst, intermediate electrocatalytic oxidation reactions (such as the oxidation of CO) take place on its surface, occupying the catalyst's active sites and lowering the effectiveness of the Pt catalyst.…”

“…The kinetics of the reaction will be dramatically improved by adding a second metal, which will also significantly boost its desorption and oxidation of the adsorbed CO. 45,[46][47][48][49] The catalytic activity of Pt and CO tolerance will be further enhanced by the cooperation of additional catalyst components or by using electrons. 11 The fine three-dimensional structure of catalysts Pt-M (M = Au, Ru, Co, Fe, Cu, or Ni) discloses additional active sites by lowering the amount of accessible precious metal atoms, [3][4][5] has recently gained interest. Pt and Pt 3 trend M's and oxygen-binding ability are shown in Fig.…”

“…Cu's metastable nature makes it possible to develop sophisticated electrocatalysts with astronomically large surface areas. [1][2][3][4]51 Cu, for instance, may be utilized to make Pt-Cu nanocatalysts both as an alloy component and as reusable in the situ-shaped template. A core-shell structure made of a Pt-Cu core and a Pt-rich shell can emerge because of the selective dissolution of Cu on the Pt-Cu surface, causing geometrical effects and ligand effects that have high catalytic reactivity to ORR.…”

“…Therefore, more durable and practical electrical energy conversion and storage methods are required to achieve more sustainable colonies with adequate renewable energy and a significant pollution reduction. [1][2][3][4] Researchers are concentrating on nuclear power and the different renewable energy sources (sunlight, wind, rain, tides, waves, geothermal energy, etc.) as alternatives to fossil fuels.…”

“…2,19 Therefore, a PEMFC must be held when the by-product doesn't evaporate more quickly than the product. 4,20 PEMFCs must be operated at a temperature of less than 100 o C. Due to their low-temperature functioning and water requirement, pure hydrogen (with a low CO concentration) must be utilized in PEMFCs. [1][2][3]21 A membrane electrode assembly (MEA) is the brain of a PEMFC.…”