S. V. Korenev

Co-Pt bimetallic catalysts for the selective oxidation of carbon monoxide in hydrogen-containing mixtures

The performance of a Co-Pt powder and of Co-Pt catalysts supported on γ-Al2O3 and on the graphite-like carbon material Sibunit in selective CO oxidation in hydrogen-containing mixtures is considered. Fine particles of metal-metal solid solutions and intermetallides were obtained by the decomposition of a Co- and Pt-containing double complex salt in a hydrogen atmosphere at ∼400°C. As compared to their Pt and Co monometallic counterparts, the bimetallic catalysts are more active and allow the CO concentration in hydrogen-containing mixtures to be reduced from 1 to 10−3 vol %. This effect is likely due to the formation of bimetallic particles of a Co-Pt solid solution on the support surface.

Synthesis and Structure of Binary Complexes of Platinum Group Metals — Precursors of Metallic Materials

This paper reviews the results of structural studies of binary complexes whose cationic part contains cobalt, rhodium, iridium, ruthenium, and chromium chloropentammne. The structure of these compounds is discussed in the light of the design of new multicomponent precursor compounds. Data are given on the chemical and phase compositions of the polymetallic powders resulting from the thermal decomposition of the compounds studied.

Low-temperature oxidation of carbon monoxide on Pd(Pt)/CeO2 catalysts prepared from complex salts

Catalysts containing cerium oxide as a support and platinum and palladium as active components for the low-temperature oxidation of carbon monoxide were studied. The catalysts were synthesized in accordance with original procedures with the use of palladium and platinum complex salts. Regardless of preparation procedure, the samples prepared with the use of only platinum precursors did not exhibit activity at a low temperature because only metal and oxide (PtO, PtO2) nanoparticles were formed on the surface of CeO2. Unlike platinum, palladium can be dispersed on the surface of CeO2 to a maximum extent up to an almost an ionic (atomic) state, and it forms mixed surface phases with cerium oxide. In a mixed palladium-platinum catalyst, the ability of platinum to undergo dispersion under the action of palladium also increased; as a result, a combined surface phase with the formula PdxPtyCeO2 − δ, which exhibits catalytic activity at low temperatures, was formed.

Bimetallic Rh-Co/ZrO2 catalysts for ethanol steam reforming into hydrogen-containing gas

The properties of supported bimetallic Rh-Co/ZrO2 catalysts in ethanol steam reforming into hydrogen-containing gas were studied. The particles of Rh-Co solid solutions on the catalyst surface were prepared by the thermal decomposition of the double complex salt [Co(NH3)6][Rh(NO2)6] and the solid solution Na3[RhCo(NO2)6]. It was found that the bimetallic Rh-Co/ZrO2 catalysts exhibited high activity in the reaction of ethanol steam reforming. The equilibrium composition of reaction products was attained at 500–700°C and a reaction mixture space velocity of 10000 h−1.

Synthesis, crystal structure, and thermal properties of [Pd(NH3)4][AuCl4]2

AbstractThe double complex salt [Pd(NH3)4][AuCl4]2 was synthesized and studied by X-ray diffraction: a = 7.5234(6) Å, b = 7.7909(5) Å, c = 8.0247(6) Å, α = 108.483(2)°, β = 106.497(2)°, γ = 99.972(3)°, V = 409.43(5) Å3, space group P % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVy0df9qqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaa0aaaeaaca% aIXaaaaaaa!361B!

Complex salts [Pd(NH3)4](ReO4)2 and [Pd(NH3)4](MnO4)2: Synthesis, structure, and thermal properties

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Polynuclear Hydroxido-Bridged Complexes of Platinum(IV) with Terminal Nitrato Ligands

, Z = 1, ρcalod = 3.456 g/cm3, R = 0.0267. The compound was characterized by powder X-ray diffraction, thermal analysis, and IR and Raman spectroscopy. The metal products of thermolysis of the complex were studied by powder X-ray diffraction.

Synergetic effect in PdAu/CeO2 catalysts for the low-temperature oxidation of CO

The speciation of platinum(IV) ions in nitric acid (6-15.8 M) solutions of H2[Pt(OH)6] has been studied by (195)Pt NMR and Raman spectroscopy. Series of aqua-hydroxo-nitrato complexes [Pt(L)(x)(NO3)(6-x)] (L = H2O or OH(-); x = 0, ..., 6) were found to exist in such solutions. The pair additivity model of chemical shifts and statistical theory were used to assign signals in NMR spectra to particular [Pt(L)(x)(NO3)(6-x)] species. Mononuclear hexanitratoplatinates(IV) have been isolated in solid state in substantial yield as pyridinium salt (PyH)2[Pt(NO3)6] and characterized by single-crystal X-ray diffraction. Aging of the platinum nitric acid solutions for more than 5-6 h results in oligomerization of [Pt(L)(x)(NO3)(6-x)] species and the formation of oligonuclear aqua-hydroxo-nitrato complexes with OH(-) and NO3(-) bridging ligands. Oligomeric platinum(IV) complexes with two and four nuclei were unambiguously detected by NMR on (195)Pt -enriched samples. Oligomers with even higher nuclearity were also detected. Dimeric anions [Pt2(μ-OH)2(NO3)8](2-) have been isolated as single crystals of tetramethylammonium salt and characterized by X-ray diffraction.