摘要:
A process is described for preparing hydrogenation catalysts which contain noble metals, having at least one catalytically active component and optionally promoters and/or modifiers on a support consisting of activated carbon washed with nitric acid. The activated carbon is subjected to an oxidative pretreatment with an oxidizing agent before applying the catalytically active components, promoters and modifiers.
摘要:
In the process and by means of the apparatus, several radiation sources (1) arranged in a row, whose emitted radiation intensity distribution is not rotationally symmetrical, are imaged by means of a first, noncentrically imaging functional element (5), then each beam bundle (9) is rotated by means of a beam-rotating element (7), and the beam components of the rotated beam bundles (9) not imaged by the first functional element (5) are imaged by means of a second, noncentrically imaging functional element (11). The functional elements (5, 11) and their locations are chosen so that parallel beam bundles (9) are produced which are focused with a spherical lens (15) into a spatial zone (3). The apparatus according to this invention provides in a simple way a good focusing ability for several individual beams.
摘要:
Iron-silicon oxide particles with a core and an outer shell have improved heating rates in a magnetic field. The core contains maghemite, magnetite, and haematite. The outer shell is essentially or exclusively silicon dioxide. The crystallite diameter of the haematite determined by X-ray diffraction is greater than 120 nm. A ratio of the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.20+/−0.02 nm, comprising maghemite and magnetite, to the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.25+/−0.02 nm, comprising maghemite, magnetite and haematite, is no more than 0.2.
摘要:
Electrocatalyst which are formed of a carbon support, which is a carbon black with an H content of >4000 ppm and, as the catalytically active component, platinum or bi- or multi-metallically doped or alloyed platinum. The electrocatalysts are prepared by deposition of noble metals on the carbon black surface. They can be used for the production of fuel cells.
摘要:
As a result of a special form of the surface coating of Al.sub.2 O.sub.3 catalysts using additional amounts of aluminum ions and very slight amounts of platinum ions, Al.sub.2 O.sub.3 was able to be used as catalyst for continuous operation (150 days and longer) in the preparation of hydrogen cyanide from hydrocarbons and ammonia, preferably in the BMA method.
摘要翻译:作为使用额外量的铝离子和非常少量的铂离子的Al 2 O 3催化剂的表面涂覆的特殊形式的结果,Al 2 O 3能够用作连续操作(150天以上)的催化剂,用于制备氢 来自烃和氨的氰化物,优选以BMA方法。
摘要:
Core-shell particles containing crystalline iron oxide in the core and amorphous silicon dioxide in the shell and in which a) the shell contains from 5 to 40% by weight of silicon dioxide, b) the core contains b1) from 60 to 95% by weight of iron oxide and b2) from 0.5 to 5% by weight of at least one doping component selected from the group consisting of aluminum, calcium, copper, magnesium, silver, titanium, yttrium, zinc, tin and zirconium, c) where the % by weight indicated are based on the core-shell particles and the sum of a) and b) is at least 98% by weight of the core-shell particles, d) the core has lattice plane spacings of 0.20 nm, 0.25 nm and 0.29 nm, in each case+/−0.02 nm, determined by means of HR-TEM.
摘要:
Iron-silicon oxide particles with a core and an outer shell have improved heating rates in a magnetic field. The core contains maghemite, magnetite, and haematite. The outer shell is essentially or exclusively silicon dioxide. The crystallite diameter of the haematite determined by X-ray diffraction is greater than 120 nm. A ratio of the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.20+/−0.02 nm, comprising maghemite and magnetite, to the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.25+/−0.02 nm, comprising maghemite, magnetite and haematite, is no more than 0.2.
摘要:
Core-shell particles containing crystalline iron oxide in the core and amorphous silicon dioxide in the shell and in which a) the shell contains from 5 to 40% by weight of silicon dioxide, b) the core contains b1) from 60 to 95% by weight of iron oxide and b2) from 0.5 to 5% by weight of at least one doping component selected from the group consisting of aluminium, calcium, copper, magnesium, silver, titanium, yttrium, zinc, tin and zirconium, c) where the % by weight indicated are based on the core-shell particles and the sum of a) and b) is at least 98% by weight of the core-shell particles, d) the core has lattice plane spacings of 0.20 nm, 0.25 nm and 0.29 nm, in each case +/−0.02 nm, determined by means of HR-TEM.
摘要:
Pyrogenically prepared zinc oxide powder having a BET surface area of from 10 to 200 m2/g, which is in the form of aggregates, the aggregates being composed of particles having different morphologies, and 0-10% of the aggregates being in a circular form, 30-50% being in an ellipsoidal form, 30-50% being in a linear form and 20-30% being in a branched form. It is prepared by reacting a starting mixture containing zinc vapour, a combustible gas and steam or a mixture of steam and carbon dioxide in a flame with an oxygen-containing gas in an oxidation zone, cooling the hot reaction mixture in a quenching zone and separating the solid material from the gas stream, the amount of oxygen in the oxidation zone being greater than the amount necessary for the complete oxidation of the combustible gas and the zinc vapour. The zinc oxide powder can be used as a constituent of sun protection compositions for protection against UV radiation.
摘要:
Pyrogenically prepared zinc oxide powder having a BET surface area of from 10 to 200 m2/g, which is in the form of aggregates, the aggregates being composed of particles having different morphologies, and 0-10% of the aggregates being in a circular form, 30-50% being in an ellipsoidal form, 30-50% being in a linear form and 20-30% being in a branched form. It is prepared by reacting a starting mixture containing zinc vapour, a combustible gas and steam or a mixture of steam and carbon dioxide in a flame with an oxygen-containing gas in an oxidation zone, cooling the hot reaction mixture in a quenching zone and separating the solid material from the gas stream, the amount of oxygen in the oxidation zone being greater than the amount necessary for the complete oxidation of the combustible gas and the zinc vapour. The zinc oxide powder can be used as a constituent of sun protection compositions for protection against UV radiation.