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Noble metal

About: Noble metal is a research topic. Over the lifetime, 15113 publications have been published within this topic receiving 337947 citations.


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TL;DR: The authors' Ag(Au)/CuPd nanoparticles are promising non-Pt catalysts for oxygen reduction reactions, with their mass activity reaching 0.20 A/mg of noble metal at -0.1 V vs Ag/AgCl (4 M KCl).
Abstract: Controlling the electronic structure and surface strain of a nanoparticle catalyst has become an important strategy to tune and to optimize its catalytic efficiency for a chemical reaction. Using density functional theory (DFT) calculations, we predicted that core/shell M/CuPd (M = Ag, Au) NPs with a 0.8 or 1.2 nm CuPd2 shell have similar but optimal surface strain and composition and may surpass Pt in catalyzing oxygen reduction reactions. We synthesized monodisperse M/CuPd NPs by the coreduction of palladium acetylacetonate and copper acetylacetonate in the presence of Ag (or Au) nanoparticles with controlled shell thicknesses of 0.4, 0.75, and 1.1 nm and CuPd compositions and evaluated their catalysis for the oxygen reduction reaction in 0.1 M KOH solution. As predicted, our Ag/Cu37Pd63 and Au/Cu40Pd60 catalysts with 0.75 and 1.1 nm shells were more efficient catalysts than the commercial Pt catalyst (Fuel Cells Store), with their mass activity reaching 0.20 A/mg of noble metal at -0.1 V vs Ag/AgCl (4 M KCl); this was over 3 times higher than that (0.06 A/mg Pt) from the commercial Pt. These Ag(Au)/CuPd nanoparticles are promising non-Pt catalysts for oxygen reduction reactions.

156 citations

Journal ArticleDOI
TL;DR: Zr-Beta zeolite is a robust and active catalyst for the Meerwein-Ponndorf-Verley reduction of levulinic acid to γ-valerolactone, a versatile intermediate for bio-fuels and chemicals as discussed by the authors.
Abstract: Zr–Beta zeolite is a robust and active catalyst for the Meerwein–Ponndorf–Verley reduction of levulinic acid to γ-valerolactone, a versatile intermediate for bio-fuels and chemicals. In a batch reactor, γ-valerolactone was formed with a selectivity of >96%. In a continuous flow reactor, >99% yield of γ-valerolactone was obtained with a steady space-time-yield of 0.46 molGVLgZr−1 h−1 within 87 h, on a par with that of noble metal based catalysts. The high activity of this catalyst was attributed to the presence of Lewis acidic sites with moderate strength. Due to the relatively few basic sites, it is not poisoned by the acidic reactant. Its robustness in liquid and gas phase reactants coupled with good thermal stability makes Zr–Beta a green regenerable catalyst that can be used directly on levulinic acid without the need for derivatization.

155 citations

Journal ArticleDOI
TL;DR: In this paper, for the first time, CdS quantum dots and carbon nanodots (CDs) were successfully co-immobilized in the cages of MIL-101 by one-step double solvents method followed by heating treatment.
Abstract: Avoiding the utilization of noble-metal cocatalyst and the aggregation of nano photocatalysts in the preparation and photocatalytic reaction are two important aspects in the area of photocatalytic H2 evolution. In this work, for the first time, CdS quantum dots and carbon nanodots (CDs) were successfully co-immobilized in the cages of MIL-101 by one-step double solvents method followed by heating treatment. The optimum photocatalytic H2-evolution rate of CD/CdS@MIL-101(50) composite with CDs content of 5.2 wt% exhibits a H2 evolution rate of 14.66 μmol h−1 without noble metal assisted under visible-light irradiation, which is 8.5 and 18.6 times higher than that of CdS@MIL-101 and bare CdS, respectively. The improved photocatalytic H2-production activity of CD/CdS@MIL-101 ternary composite is predominantly attributed to the effect of CDs, which mainly serves as an electron collector to efficiently prolong the lifetime of the photogenerated charge carriers from CdS@MIL-101 heterostructure. This work provide a new strategy of one-step double solvents method to co-incorporate two functional species to the pores of metal-organic frameworks (MOFs) to improve the photocatalytic H2 evolution activity of host photocatalyst.

155 citations

Journal ArticleDOI
TL;DR: In this paper, the pre-steady-state oxidation of a wide range of binary alloys of practical importance, in 1 atm oxygen at 600° C, is discussed in terms of the main determining parameters, namely the free energies of formation and growth rates of the component and complex oxides, the bulk alloy composition, the alloy interdiffusion coefficient, the oxygen solubility and diffusivity in the alloy, and effects such as epitaxy.
Abstract: The pre-steady-state oxidation of a wide range of binary alloys of practical importance, in 1 atm oxygen at 600° C, is discussed in terms of the main determining parameters, namely the free energies of formation and growth rates of the component and complex oxides, the bulk alloy composition, the alloy interdiffusion coefficient, the oxygen solubility and diffusivity in the alloy, and effects such as epitaxy. Schematic diagrams are used to illustrate the morphology and structure of the films, as revealed by electron microscopy and diffraction. After tabulation of the sparse, and often apparently unreliable, fundamental parameters, a comparison is made within each of the following groups of alloys: (1) Fe-Cr, Ni-Cr, and Co-Cr alloys, in which the less noble metal is the same and the noble metal is varied, there being composition ranges in which noble metal oxide and less noble metal oxide respectively predominate but in which the oxides are partially miscible or react. (2) Ni-Al, Ni-Cr, Ni-Si, Ni-Mn, and Ni-Co alloys, in which the noble metal is the same, the less noble metals have a wide range of affinities for oxygen and oxidation rates, and the oxide phases produced include solid solutions, largely immiscible simple oxides, and complex oxides. (3) Cu-Ni, Cu-Zn, and Cu-Al alloys, in which the noble metal is the same and the less noble metal is varied, the oxides being largely immiscible.

155 citations

Journal ArticleDOI
TL;DR: In this article, the authors developed Co9S8 particles in situ grown on nitrogen and sulfur co-doped porous carbon to replace the benchmark noble metal catalysts, which shows high catalytic activities including small potential gap, long-term durability and high selectivity.
Abstract: Oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are still kinetic barriers of regenerative fuel cell and metal–air batteries, requiring efficient and inexpensive bifunctional electrocatalysts to accelerate the reaction and improve energy efficiency. Herein, we develop Co9S8 particles in situ grown on nitrogen and sulfur co-doped porous carbon (Co9S8/NSPC) to replace the benchmark noble metal catalysts, which shows high catalytic activities including small potential gap, long-term durability and high selectivity. Importantly, the Zn–air battery with Co9S8/NSPC as air electrode displays low discharge/charge overpotential and good cyclic stability, making it the promising bifunctional catalyst for the practical applications.

155 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023485
2022986
2021622
2020724
2019896
2018767