نتایج جستجو برای: pt
تعداد نتایج: 46502 فیلتر نتایج به سال:
هدف از این مطالعه طراحی یک روش کلی برای سنتز یک سری از کمپلکس های دو هسته ای متقارن سیکلومتاله شده پلاتین (ii) بوده که دارای یک لیگاند پل زن(1,2-bis[bis(pentafluoro-phenyl)phosphino]ethane),dfppe, است. از واکنش cis-[pt(r)2(sme2)2]، که در آنr= para-tolyl ، با یک اکی والان از لیگاند benzo[h]quinoline,bhq، در استون محصول [pt(r)(bhq)(sme2)] که در آن r= para-tolyl بدست می آید. همچنین از واکنش 5/0 اک...
The electrochemical activity and durability of Pt nanoparticles on different kinds of carbon supports in oxygen reduction reactions (ORR) were investigated using rotating disc electrodes (RDE) and the membrane electrode assemblies (MEA) of polymer electrolyte fuel cells (PEFC). The mass activity of Pt/C catalysts (ORR activity per 1 mg of Pt) at the RDE decreased, according to the type of carbo...
Conventional supported Pt catalysts have often been prepared by loading Pt onto commercial supports, such as SiO2, TiO2, Al2O3, and carbon. These catalysts usually have simple metal-support (i.e., Pt-SiO2) interfaces. To tune the catalytic performance of supported Pt catalysts, it is desirable to modify the metal-support interfaces by incorporating an oxide additive into the catalyst formula. H...
Carbon-supported Pt–Ru alloys with a Pt/Ru ratio of 1:1 were prepared by NaBH4 reduction at room temperature. X-ray diffraction (XRD) measurements indicate that the as-prepared Pt–Ru nanoparticles had a face-centered cubic (fcc) structure. X-ray photoelectron spectroscopy (XPS) analyses demonstrate that alloying with Ru can decrease the 4f electron density of Pt, which results in a positive bin...
Taming interfacial electronic effects on Pt nanoparticles modulated by their concomitants has emerged as an intriguing approach to optimize Pt catalytic performance. Here, we report Pt nanoparticles assembled on vacancy-abundant hexagonal boron nitride nanosheets and their use as a model catalyst to embrace an interfacial electronic effect on Pt induced by the nanosheets with N-vacancies and B-...
Energetic stability and electronic structures of Pt atoms in Pt-Rh nanoparticle is investigated by first-principles calculation. Pt atom energetically prefer surface sites (vertex, edge, and (100)) rather than subsurface and core site, which is attributed to lower Pt surface energy compared with Rh. Vertex of nanoparticle is the most favorable site for Pt atom, which has lowest coordination num...
Enhanced performance was observed for dye-sensitized solar cells (DSSCs) utilizing counter electrodes based on Pt electrodeposits compared to counter electrodes based on sputtered Pt. Scanning electron microscopy of Pt electrodeposits revealed that the use of an initial cathodic overpotential pulse followed by steady electrodeposition at a mild cathodic potential yielded ∼40nm particles, compar...
The hydroisomerization of n-butane was carried out in a fixed-bed gas-flow reactor over Pt-promoted Cs2.5H0.5PW12O40 (denoted as Cs2.5). Two kinds of catalysts, a direct impregnation of Pt on Cs2.5 (denoted as Pt/Cs2.5), as well as a mechanical mixture of Pt/Al2O3 and Cs2.5 (denoted as Pt/Al2O3+Cs2.5), were used for the hydroisomerization. Pt/Al2O3+Cs2.5 showed a higher stationary activity than...
Size-controllable Pt nanoparticles ranging from 1.3 to 2.3 nm were successfully loaded onto ZSM-5 (Pt-x/ZSM-5, where x is the mean diameter of the Pt nanoparticles). Catalytic tests in complete oxidation of toluene as a model for VOC removal show that Pt-1.9/ZSM-5 has the highest activity, due to a balance of Pt dispersion and Pt(0) proportion.
The Pt@Au catalysts demonstrate remarkably high oxygen reduction reaction (ORR) activity compared with Pt/C catalysts. The ORR of Pt(2)@Au(1)/C and Pt(1)@Au(2)/C is 9.5 and 6.6 times that of Pt/C, respectively. This improvement is attributed to the electronic structure effect of the Au core on the Pt shell and introduction of PFSA.
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