JPS6161643A - Catalyst composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The catalyst of the present invention comprises a small surface area particulate carrier or substrate and a thin film composite deposit sputtered onto the substrate.

The carrier material has a small surface area and is stable at the reaction conditions used. Refractory material, for example 5in2. AI Yu0□TiO
2. Oxides such as MgO, Sin: , and S r s N+.

Glasses satisfying stability requirements can also be used, with nitrides and carbides being preferred. Particularly preferred are Al2O and 5in2L. The surface area of the granular carrier is preferably l
Zero particle size of less than Om''/g is not critical, but for ease of manufacture, 100 gm or more is preferred, as described below.

Sputtered thin film composite deposits include Pt, Pd, Ag
, Au, Re, Rh, Ru and Irc7)
or more catalytically active metals and co-sputter carrier materials. The co-sputter carrier material is preferably an oxide, nitride or carbide, more preferably the same material as the particulate carrier material to obtain good bonding and adhesion to the substrate. Particularly preferred as co-sputter carrier material and carrier material are oxides A1□0. and SiO□.

Composite sputter coatings, or deposits, can be made from a single target of metal and co-sputtered carrier material or from separate targets of metal or alloy and co-sputtered carrier material.
produced by simultaneous or subsequent sputtering from To explain the case where the composite sputtered material includes two metals and a co-sputter carrier material, l, 2,
Or you can use 3 targets. One target is made from all three substances. The two targets consist of one column and one co-sputtered carrier material, or one metal-strong sputtered carrier material and one other metal. The three targets consist of a respective target of each metal and a co-sputter carrier material.

Preferably, the composite sputter deposit is a homogeneous mixture of each component. This is easily achieved by generating all components from a single target. In this case, the granular material can be mixed by vibration or rotation during sputtering, for example by vibrating blood particles connected to a piezoelectric driver or an audio speaker, or by hand stirring by an operating arm connected to a dish. When sputtering simultaneously/successively from multiple targets, the sputtering is interrupted several times and the particles are mixed outside the sputtering chamber. mixed in.

In the case of multiple target particles, it is necessary to rotate the table on which the carrier particles rest in order to provide a good mixture of the sputtered components. The rotation speed of the table per minute is fast enough for good mixing of the components. In the case of the Ag/SiO□ composite produced with such rotation, compound line diffraction and transmission electron microscopy confirmed that the composite film consisted of Ag particles with a diameter of less than 100 Ω dispersed in an amorphous 5 iOz matrix. Ta. Preferred carrier particle dimensions are greater than 100 lumens. If it is less than this, it is difficult to mix the particles and coat them sufficiently. The upper size limit is limited only by its usefulness as a catalyst support in the equipment and process used.

RF sputtering in particular is compatible with preferred co-sputter carrier material targets. @First, evacuate the sputtering chamber to 10 to 10 torr using a conventional vacuum pump. A small amount of argon gas is supplied and a 13.58 MHz ionizing RF field is applied between the target material to be sputtered and the carrier table. Positively charged argon ions are accelerated toward a target at negative potential. Argon ions hit the target metal species,
This adheres onto the carrier. The pressure of argon is usually 5×
10-20X10 torr, but other pressures can also be used. Although other inert gases such as neon, krypton, and xenon can be used, the preferred method is R because argon is cheap, easy to handle, and has a good sputtering yield.
Not limited to F sputtering, other sputtering,
For example, it can be performed either by ion beam sputtering using another accelerated ion source, or by RF or DO magnetron (enhanced magnetic field) sputtering.

An advantage of sputtering from multiple targets is that by changing the voltage on each target, the composition of the co-sputtered catalyst can be varied.

For example, when forming a composition of 8g/5iO2L on fused silica particles, the 1g9-gate (1) voltage is 100V, 250V for a 5iOz target of about 1500V.
, In experiments of the same duration with 'dJfD at 500V, 750v and 100OV, the C degree of 88 was 0.0 respectively.
38%, 0.175%, 0.83%, 1.22% and 1
．． 87% (based on the total weight of substrate and sputtered composite). In this voltage range, the volume concentration of Ag in the sputter deposit is 4% (100V) and 70%
(100OV), remainder (fsi02., gusset changed).

Sputtering of multi-metal catalysts from separate metal and non-metal targets, e.g. Ag/on 5iOL
In Au/5iO1, the metal ratio can also be controlled by the target voltage. The Ag/Au/5i01 film has an Ag/Au atomic ratio of 3515.88/12,
It was possible to manufacture it in 75/25, 85/35 and 60ha0.

These ratios are (where R is the sputtering rate and V
is the sputtering voltage) (e.g. Handbook of Th1n fi
lm Technology, Maissel and
Gland) and depends on the sputtering voltage. The relative concentration of total metals to non-metals is determined by the total metal target voltage (
It can be controlled by adjusting VA, +-).

The Ag/Au/Sin□ composite VI film can be manufactured by sputtering from an Ag/Au alloy tarpunto O□ target. Fused silica with atomic ratio of 130 Ag OA
Coated by sputtering from a U alloy target and a 5j02 target. Alloy target voltage 500v, 750v and tooov for 5i02 of about 1500v
In the sputtering experiment of 1#J1 with the same duration, the metal concentration was 0.46-1.15-1.79% by weight.
It changed to Ag/A in the film in all cases
The u atomic ratio is 80, which is the same as the target, according to atomic absorption analysis.
It was confirmed that it was Ag/40 Au.

Ag/5i02 or Ag/^u/5s02 coatings can also be produced from a single composite target. For example, the Ag/SiO□ target is ball milled from finely ground Ag and Sr02 powders in a weight ratio of 88/12. It can be manufactured by mixing inside. Mixed powder is 10,0001bg
It was compressed into a 2-inch diameter disc at
Bake for 6 hours. The obtained disks are used as targets in the production of composite catalysts. X-ray diffraction of thin films obtained from these targets confirmed fine Ag particles with a diameter of about 55λ dispersed in an amorphous silica matrix. These results demonstrate that separate Ag and Si on a rotating substrate
Similar to that obtained by sputtering from an O□ target.

The surface area of sputtered composite deposits increases as the thickness of the coating film increases, as opposed to the surface area of smooth deposited or sputtered metal films, which is independent of film thickness. This means that # of rotary base table L is
Table 1 describes Ag/SiO2 composite deposits prepared by sputtering fused silica particles from separate Ag and SiO□ targets.

1-±-1 Silver target voltage Sputtering time Surface area V Porto-E Asahi, Ni Engineering 11□500
3 0.112500
8 0.1837
50 3 0.
124750 8
0.2451000 3
0.1491000
fi 0.313 The surface area of the molten silicon particles themselves is negligible (< 0.03+a
"/g), so the surface area of the coating particles is attributed to the deposits. From the measurement of the actual amount of metal, the surface area of the metal alone in Table 1 was determined to be about 20 m"/g.

The catalytic action of wood IJJ was demonstrated by a number of specific methods.

Ag/SiO2 sputtered on small surface area fused silica
The catalyst is more active for formaldehyde synthesis from methanol by oxidative dehydrogenation than Ag alone catalyst sputtered onto the same carrier particles, and is only 1/1 as active as bulk Ag.
00 AgM), yet it gives at least the same yield at high conversions of methanol and 1-2% more yield at low conversions. Ag/MgO and Ag/Au/SiO on fused silica particles
□High activity, selectivity and stability of deposits can be obtained at commercial flow rates.

Sputtered Pd/! onto small surface area fused silica! Jim
The z-film catalyst exhibits high stability as a hydrogenation catalyst in peroxide synthesis.

[Example] A catalyst consisting of a fused silica heglsioz composite
g and 5i02. were manufactured by simultaneous RF sputtering from separate targets. Fused silica particles (average size approximately 2 mm) were placed in several Pyrex dishes on a rotating substrate table below the target and coated with the sputtered deposit. About 1 m<2>/g of fused silica was used in Examples 1-3 and about 14 g in Example 4. The voltages applied to each target are shown in Table 2.

Eave-E-1 Example Silver target voltage Silica target-Hiyo VA Porto IL Sumiran (L mouth 4
1000 140G In each example, the argon pressure was maintained at 8XlO=Torr and the particulate carrier was rotated at 5 revolutions/min. Sputtering continued for 6 hours with periodic particle mixing outside the sputtering chamber.

These catalysts were then used in the synthesis of formaldehyde from methanol. The method and experimental technique are covered by U.S. Patent No. 4.
No. 21.9509 (Rao and Nelsen). For a given conversion of methanol to formaldehyde, yields using the composite catalyst were greater at low conversions and at least as high at high conversions than with bulk silver, but 6° Ag was 1/+0 lower than that of bulk Ag catalyst.
It was only 0. "Methanol conversion" means the number of moles of methanol converted to other products per mole of methanol fed.

"Formaldehyde selectivity" means the number of moles of formaldehyde formed per mole of methanol converted. 0 wt% metal (e.g., WtXAg) means the weight of metal divided by the combined weight of support and sputter deposits. then 100
means the multiplied value. The results are shown in Table 3 together with the bulk silver results.

Ag/Mg sputtered onto fused silica by RF sputtering from separate targets of Ag and gO
Approximately 17 g of fused silica (average size 2 as) was sputter coated on several Pyrex pans on an O-rotary table that produced a catalyst consisting of an O-composite. Sputter voltage was 500V on Ag and 1200V on MgO. The argon pressure was maintained at 3×10 ) and the granular support was rotated for 5 revolutions in 1 minute.

The sputtering time was 8 hours, and the particles were mixed periodically outside the sputtering chamber.

This catalyst was used for the synthesis of formaldehyde and the results are shown in Table 3.

An Ag/SiO1 composite catalyst was produced by RF sputtering from a composite solid target in which Ag and SiO were homogeneously mixed at a Ag/5i02 weight ratio of 88/12. 1
approximately m2/g of fused silica particles in Pyrex blood (
2 mm in average size) were sputter coated. During sputtering, an arm-mounted dish in the vacuum chamber was moved mechanically to mix the particles. Target voltage is 220
0 V, argon pressure was 8×10 and sputtering time was 2 hours.

Table 3 shows the results of the poems used in the synthesis of formaldehyde.

By simultaneous RF battering from 15M1 Ag/Au alloy target and 5iOz target, A containing 45% gold
The composition of the 0 alloy target from which the g/Au/SiO□ composite contact was made was 130 atomic % Ag and 40 atomic % Au. Approximately 10 g of fused silica particles distributed in several Pyrex pans on rotary table L2 below the target were coated with sputter deposits. The sputtering voltage was 500V for the 1-alloy target and 1700V for the SiO□ target. The argon pressure was maintained at 8×10 ) and the particles were rotated at 5 revolutions/min. The sputtering time was 4 hours, and the particles were mixed periodically outside the sputtering chamber. Example 7(a) uses 60/40 Ag/Au as catalyst.
It is a control using alloy tentacles.

The catalyst was used for the synthesis of formaldehyde. 3rd result
Shown in the table.

Applicant's attorney's payment 1: Example by Takehiko Suzue Weight %Ag, Ag/Au molar ratio -
Momoichi , -, F-Gile Otsugo Enijo A Bulk (Ag) 0.2800.360 1 0, 180 0.284 (
Ag/5iOa) 0.3032
0.63 0.28 (Ag/SiO
□) 0.3803 1
．． 2 0.285 (Ag/S
iO□) a, 3854
2.05 0.288 (Ag
/Sin□) 0.3515
0.58 0.284
(Ag/MgO) 6 2.0
0.23B (Ag/Sin□) 7 4.5
0.258 (Ag/＾u/SiO□) 7(a) /<Luku(Ag/Au)
0.236～-diL - per person per bed temperature Converted methanol Formaldehyde selectivity °C - 11110 84.0 75.2 92.4
700 91.0 92.7f
19Q 6 [f, 9 94.
170G 77.8 93.
8895 75.4
93.071G 94.3
92.0695 7[1,79
3,070090,192,8

Claims (1)

[Claims] 1. A particulate carrier having a surface area of 10 m^2/g or less and a particle size of 100 μm or more, and a catalytically active metal and co-sputtered carrier material sputtered and closely adhered on the surface thereof, A composite catalyst in which the catalytically active metal is 0.01-5.0% by weight of the total catalyst and 3-80% by volume of the sputtered deposit. 2. The catalyst according to claim 1, characterized in that the co-sputter carrier material has the same composition as the particulate carrier. 3. The catalyst according to claim 1, item 2, wherein the granular carrier is a refractory. 4. The catalyst according to claim 3, wherein the particulate carrier is an oxide, nitride, or carbide. 5. The granular carrier is SiO_2, Al_2O_3, TiO_
2. The catalyst according to claim 4, characterized in that it is SiC or Si_3N_4. 6. Catalytically active metal is Pt, Pd, Ag, Au, Re, R
6. Catalyst according to claim 5, characterized in that it is Ru, Ru or Ir, or a mixture thereof. 7. The granular carrier is Al_2O_3, SiO_2 or Mg
7. Catalyst according to claim 6, characterized in that O. 8. Catalytically active metal is Ag, Ag/Au, Pd, or p
Catalyst according to claim 7, characterized in that t.