Synergistic Effects of Gold-Palladium Nanoalloys and Reducible Supports on the Catalytic Reduction of 4-Nitrophenol.

Title Synergistic Effects of Gold-Palladium Nanoalloys and Reducible Supports on the Catalytic Reduction of 4-Nitrophenol.
Authors N. Bingwa; R. Patala; J.H. Noh; M.J. Ndolomingo; S. Tetyana; S. Bewana; R. Meijboom
Journal Langmuir
DOI 10.1021/acs.langmuir.7b00903
Abstract

Herein we report on the catalytic activity of mesoporous nickel, iron, cerium, cobalt, and manganese oxides prepared using KIT-6 as a hard template via evaporation-assisted precipitation. The mesoporous metal oxides (MMOs) were characterized and used as heterogeneous catalysts in the reduction of 4-nitrophenol (4-Nip) by sodium borohydride (BH4(-)). Furthermore, polyamidoamide (PAMAM) dendrimers were used to synthesize gold-palladium nanoalloy particles. The size of AuPd/PAMAM was found to be 3.5 ± 0.8 nm in diameter before being immobilized on the aforementioned mesoporous metal oxides and used as catalysts in the reduction of 4-Nip. Prior to catalytic evaluation, the reduction profiles of the mesoporous metal oxides were investigated by hydrogen-temperature-programmed reduction (H2-TPR) and showed that mesoporous metal oxides can be easily reduced at lower temperatures and that the immobilization of gold-palladium nanoalloy particles lowers their reduction temperatures. Mesoporous cobalt and manganese oxides showed catalytic activity toward 4-Nip reduction, and the activity was enhanced after immobilization of the gold-palladium nanoalloys. Isolation of nanoparticles activity was achieved by immobilization of the gold-palladium nanoalloys on the inert silica support. From this we postulated an electron relay mechanism for the reduction of 4-nitrophenol. With the use of power rate law we showed that 4-Nip reduction follows pseudo-first-order kinetics.

Citation N. Bingwa; R. Patala; J.H. Noh; M.J. Ndolomingo; S. Tetyana; S. Bewana; R. Meijboom.Synergistic Effects of Gold-Palladium Nanoalloys and Reducible Supports on the Catalytic Reduction of 4-Nitrophenol.. Langmuir. 2017. doi:10.1021/acs.langmuir.7b00903

Related Elements

Palladium

Palladium Bohr ModelSee more Palladium products. Palladium (atomic symbol: Pd, atomic number: 46) is a Block D, Group 10, Period 5 element with an atomic weight of 106.42. The number of electrons in each of palladium's shells is 2, 8, 18, 18 and its electron configuration is [Kr] 4d10. The palladium atom has a radius of 137 pm and a Van der Waals radius of 202 pm. In its elemental form, palladium has a silvery white appearance. Palladium is a member of the platinum group of metals (along with platinum, rhodium, ruthenium, iridium and osmium). Elemental PalladiumPalladium has the lowest melting point and is the least dense of the group. Palladium can be found as a free metal and alloyed with other platinum-group metals. Nickel-copper deposits are the main commercial source of palladium. Palladium was discovered and first isolated by William Hyde Wollaston in 1803. Its name is derived from the asteroid Pallas.

Gold

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