TWI293061B - Process of producing hydrogen using au/zro2 catalysts - Google Patents

Description

1293061 IX. Description of the invention: [Technical field to which the invention pertains] The present invention is a process for producing hydrogen gas using a zirconia support gold catalyst, which is used for producing helium gas and == reducing the carbon monoxide content by twist. The zirconia prepared by the invention has a spherical gold crystal grain with a shape of more than 0.5 nm. The catalyst is prepared by the precipitation 2= method for taking commercial ceria as a support dissolved in pure water to prepare an aqueous solution. The pH of the aqueous solution is controlled to be 7 by using sodium carbonate of 0,1 molar concentration, and gradually dropping. Aqueous acid gold solution, after several times of water washing and filtration after sedimentation, dry furnace at 1 〇〇t\ change the different calcination temperature 3GG~6GG. The methanol oxidation reaction is carried out at a reaction temperature of 23 G to 29 G ° C to exert optimum activity and hydrogen selectivity. The precipitation of 2 ruthenium oxide supported gold catalyst by precipitation method can reach more than 85% of methanol at 290 〇C, 87% of hydrogen can be selected, and no carbon monoxide is produced. The method disclosed in the invention prepares the dioxins, and the gold-bearing catalyst has a gold crystal grain of less than 5 nm larger than G.5 nm, which is difficult to catalyze the partial oxidation of methanol to oxidize carbon-oxygen. The product towel did not have carbon monoxide contamination. [Prior Art] The catalyst "is actually a chemical substance, and it is called a catalyst chemically. Catalysts can cause chemical reactions to occur or accelerate the reaction. With human energy, driving machinery, and having a huge impact on civilization, but then it is the destruction of the environment, such as the greenhouse effect and air and water pollution, is a common crisis facing all things on the planet. Therefore, it is imperative to develop high-efficiency and low-pollution energy. In recent years, the technology of generating electricity with “hydr〇gen energy” has been continuously improved, and its commercialization prospects are just around the corner. It not only reduces the pollution of exhaust gas, but also avoids the problem of time-consuming charging of traditional batteries. Due to the considerable difficulty in transporting and storing hydrogen, we must choose the appropriate source of hydrogen as the fuel used in the fuel cell. At present, hydrocarbons such as methanol, natural gas and light oil are mainly used as alternative hydrogen sources. Among them, methanol has high fuel quality, low price, convenient access, easy storage and convenient transportation (Joensen and Rostrup-Nuelsen, published in J. Qing, vol.105. 1293061 pl95, published in 2002); and in low response Hydrogen can be formed by reaction at a temperature of 200 to 400 °C. Compared with traditional gasoline fuel, the generated oxidizing agent (C〇2) is reduced by about 50%, and there is no air pollution source such as NOx, SOx, hydrocarbons, etc. The fuel cell is a big profit. Gold has long been described as a less active catalyst because of its chemical inertness and high dispersion difficulties. It was not until Haruta et al. discovered that the gold catalyst of the support had the ability to oxidize carbon monoxide at low temperatures in "/. Cato/., vol. 155, p301, 1989. Hydrogen production from methanol can be obtained by the following four catalytic reaction pathways: (1) (2) (3) (4) methanol decomposition (MD) reaction

CH, ΟΗ 2Η2 + CO Steam reforming of methanol (SRM) reaction CH3OH + H20 3H2 + C02 Partial oxidation of methanol (POM) reaction CH 3OH + l/202 2H2 + C02 Methanol oxidizing steam Oxidation steam reforming of methanol (OSRM) reaction 2CH3OH +1/202 + H20 ^ 5H2 + 2C02 Industrial hydrogen production is often carried out using steam recombination reactions. Generally, the catalytic effect can be achieved with a copper catalyst, which has a good reactivity at 200 °C. Unfortunately, a large amount of carbon monoxide (>1%) is present in the methanol vapor reforming product, causing the poisoning of the platinum electrode of the proton exchange membrane fuel cell to cause a decrease in battery power (Sekizawa et al. in 々?〆A, νο1·169, ρ291 ,1998). Therefore, selective hydrogen permeable membranes (Emonts et al. J for gastric gas removal, νο1 71, ρ288, 1998), selective CO oxidation, water gas shift reaction and other additional equipment are needed to reduce the amount of carbon monoxide. The preparation method of gold catalysts in the literature is a total of the temple method (c〇_precipitati〇n) (Haruta,

Cato/· ΓοΑ brother vol.36, pi53, 1997), impregnation method (Lin et al., hunger, vol.17' p245, 1993), sedation method (dep〇siti〇n_precipitation) (Haruta et al. 1 Cato/·, vol. 144, pl 75, 1993), gas-phase grafting (Okumura Leii·, p315, 1998), liquid-phase grafting, colloid Colloid-mixing ° The process of various common methods for preparing gold-supported catalysts will be briefly described below. (1) Coprecipitation method: First, a gold chlorate aqueous solution and a nitrate metal are mixed, and titrated with a sodium carbonate aqueous solution to form a hydroxide or carbonate coprecipitate. The catalyst precursor is washed, filtered, dried, and finally calcined in air.

(2) Sinking fixation method: adding an aqueous solution of oleic acid to the oxide support, and adjusting the pH between 6 and 10 using an aqueous solution of sodium carbonate. After aging for one hour, hydrogenated gold is produced on the surface of the catalyst. The catalyst precursor is washed with water, filtered, dried, and finally calcined under air.

(3) Impregnation method: first dissolve gold chlorate in water, and then thoroughly mix the prepared solution with the carrier to be loaded. After drying, a fresh sample is obtained. (4) Co-sputtering method · At a large pressure, oxygen, gold and metal oxide are simultaneously sputter deposited on the substrate to form a film, which is finally annealed under air.

▲ A variety of different preparation methods have their advantages and disadvantages. The gold catalyst prepared by the impregnation method has lower dispersion and poor catalytic activity. The gold particle size is about 8.3 〇 nano _ shirt in ^ Cata V0LI44, pl75, I" 3 years published). The reason for the low activity may be due to the precursor of gold (4): b) usually chloride. Low-temperature calcination will have a large number of scales in front of the carrier and poisoning the phenomenon of sintering between the medium and the medium. Usually, it is really necessary to use a small particle gold carrier catalyst (<5 legs). The equipment used for hanging is a combination of the temple method and the stagnation method. In 2, 3 years, it is mentioned that different kinds of catalyst carriers have different effects. The above method can oxidize the metal grains of the semi-spherical ball with good thermal stability. Gmnwaldt et al. in j Cakd ::, Guang 8_-, 1999, pointed out that the oxidized _ gold-bearing surface _ calcined crystals will grow to 4-6 nm or change shape into a symmetrical hexagon. ^ Release the ilf to the active site of the catalyst. Mawikakis et al. (10) Guan Chuan. The reaction time of gold a / ^ fine cast age is closely related to the record carrier. The higher the oxygen atom concentration is ΐ, which will make the edge gold atom illuminate the same emulsification activity. B〇c(四)zi et al. C*/· L hunger, voL44 7 1293061 p83, 2GG^ _ The gold atoms on the plane of the room temperature do not adsorb _ oxidized carbon, which only adsorbs on the gold, the edge, the edge and the corner On the atom. In 1999, Park and Lee studied the ratio of the metallic metal (Au metal) and the oxidized gold (Au(〇H)3, Au2〇3) at different calcination temperatures, and found that the higher the forging The firing temperature causes the metallic gold on the surface of the catalyst to increase. However, there is no significant increase in activity for the oxidation of carbon monoxide, so gold in the oxidized state is more active than carbon in the oxidation of carbon monoxide. However, he argued in Cato/See, v〇1 36, pl53, 1997 and Grisel et al. Qto/· Γο~, ν〇ΐ·72, 1_2, p123_pl32, in 2002, the opposite opinion. They believe that metallic gold is the active site for the oxidation of carbon monoxide. The traditional petrochemical process performs steam recombination reaction by indirect heating to produce hydrogen-rich heavy Φ gas. The concentration of carbon monoxide is about 13~2〇% (in dry), and then the carbon monoxide is reduced to 〇5~2% by water-gas shift reaction (Water-Gas Shift, WGS). Conventional petrochemical industry usually uses Catalyst Fe304-Cr03/Al203 and Cu-ZnO/Al2〇3 catalyst for catalytic reaction. For example, (4) et al. j C^to/·, ν〇1·158, p354, in 1996, attempted to use the iron oxide-supported gold catalyst and alumina-supported gold catalyst to catalyze the steam recombination reaction, indicating that at low temperatures The iron oxide supported gold catalyst is active, but the oxidized gold catalyst is not, and the activity of the ferric oxide-supporting gold catalyst is much higher than that of the alumina-supported gold catalyst and other commercial catalysts at high temperatures. . The nickel hydroxide-supported gold catalyst was also found to be active in the -water vapor recombination reaction. After comparing the catalytic effects of the ferric oxide-supported gold catalyst, the cobalt trioxide-supporting gold catalyst, and the titanium dioxide-supported gold catalyst, it was found that the titanium dioxide-supported gold-g catalyst is more efficient for the steam recombination reaction. Catalyst. In academic research, steel catalysts were also commonly used in the early part of the methanol oxidation reaction. This is another major way to make it. Huang and Wang in the Liu /. c theory /, p287, in 1986 in the f alcohol evaporation & recombination reaction into the oxygen, found that higher hydrogen yield can be obtained. From the discussion of the kinetic mechanism of methanol partial oxidation reaction, Huang and Chren also determined that the methanol conversion rate would increase due to oxygen addition in (4)^, νο1·40, ρ43, 1988. The dissociative adsorption is a rate determining step. In recent years, Cubek〇 and FiejT〇 have been studied in 々7/7/· CWto/·, Α νο1·, 168, p307-p322, 1998, using a palladium catalyst for partial oxidation of methanol. It has been observed that even if there is a considerable difference in the surface area of the catalyst, both the oxidation word and the oxidation error have good catalytic activity. However, when the methanol partial oxidation reaction is carried out by the i cancer non-oxidative support medium, a large amount of carbon monoxide is generated. This is because the reaction tends to directly decompose methanol 8 1293061. In the application of electric vehicle fuel cells, methanol reforming reaction (SRM) and partial oxidation of methanol (partiai 〇xjdati〇n 〇f methan〇i, pom) are often utilized to generate hydrogen. Among them, the partial oxidation reaction of methanol is an exothermic reaction, and not only oxygen (〇2) can be used instead of steam as an oxidant, and an additional heating source is not required to continuously supply heat, so that a large amount of research has been conducted in recent years. Huang and Wang 〆Cato/·, vol.24, p287. In 1986, oxygen was first added to the methanol-hydrogenation recombination reaction, and a partial catalytic oxidation of methanol was carried out using a copper-catalyst.

Krnnar et al. (1992) published a catalyst for catalyzing methanol in zinc oxide-supported steel catalysts at the Argon National Laboratory.

Deng hurts the oxidation reaction. Later, Alej0 et al., p/q^/., A, vol.162, p281-p297, found in 1997 that zinc oxide-loaded steel catalyst activity is directly related to the surface area of copper metal. In addition, they also added alumina in the oxidized copper-carrying catalyst. Although Al2O3 helps to increase the stability of the tactile and prolonged production time, the land removal slightly reduces the methanol conversion rate. W Newg et al. J. Ship, vol. 191, P123-pl34, attempted to add zinc in copper/complex and copper-supported copper catalyst in 2003. Research indicates that adding words can not only improve the activity of the catalyst, but also the help of the knowledge and nature of the catalyst. However, the addition of an excessive amount of system causes a large test of the formation of copper oxide, which in turn reduces the activity. Some scholars use non-steel catalysts for methanol partial oxidation catalysis. Cubdr〇 —

In (5), ·, t, voU68, p307, published in 1998, the choice of 1 bar catalyst for catalytic research. research. Whether it is oxidation or chromium dioxide as a support, it has good catalytic activity. However, partial oxidation of methanol is carried out with 1 wt% dioxins-catalyst, and the reaction tends to directly decompose methanol to form a large amount of carbon monoxide. Professor Ye Junxi and others in the 2GG2 year of the reaction (four) shot paper towel compared to the preparation of the supporting gold catalyst by the Shen_ method to carry out a (four) part of the oxidation anti-lining test 'discovery of the increase in the methanol feed molar ratio increased . When the oxygen/methanol feed molar ratio is approximately equal to 〇5, the yield of the new product will be the highest. The _ gold_Dulin's partial yttrium oxide is produced, and the new network is mixed. The oxygen-emitting scale has a good '° silk selectivity' and - the production of carbon oxide is less than 1_ ppm. However, Oxide Ming 9 1293061 has a poor selection rate of hydrogen supported on gold catalyst, and the preparation of peak #士 s 曰 produces methyl formate. The use of gold catalyst can produce low-oxidation of antimony-containing nitrogen, which is due to the fact that the PEFC & The use of gold catalyst on carbon monoxide does not have the patent for the preparation of hydrogen as in the case of dimethyl hydrazine and ft minus 4 in this case. The current patents relating to the gold catalysts are listed in Table 2. The current patents relating to gold catalysts in the United States are listed in the method of using a oxidized staggered gold catalyst to produce helium gas as disclosed in the A patent. - Guan Guan Patent Announcement No. Announcement Date Patent Name 1 00534833 2003/06/01 Palladium-Gold Catalyst for the Production of Vinyl Acetate 2 00222233 1994/04/11 Preparation Method of Gold Catalyst for Oxidation of Carbon Monoxide 3 00145039 1990/ 11/01 Used in the discharge of carbon dioxide lasers. Gold catalysts are shown in Table 1. The second is about the production of hydrogen related patents. Announcement date Patent name 1 00553898 2003/09/21 Promoting biological sludge with thermal pretreatment Method of producing hydrogen 1293061

参二·US About the Golden Catalyst Related Patent Notice No. Announcement Date Patent Name 1, 6,509, 293 January 21 ? 2003 Gold based heterogeneous carbonylation catalysts 2 6,506,933 January 14, 2003 Vapor phase carbonylation process using gold catalysts 3 6,022,823 February 8, 2000 Process for the production Of supported palladium-gold catalysts 4 5,550,093 August 27, 1996 Preparation of supported gold catalysts for carbon monoxide oxidation 5 5,336,802 August 9, 1994 Pretreatment of palladium- gold catalysts useful in vinyl acetate synthesis 6 5,051,394 September 24, 1991 Method for production of ultra- Fine gold particle-immobilized oxides

[Summary of the Invention] = The process of _ oxidized staggered gold production system, the wire produces hydrogen, and fixes the gold crystal grains of the 余 ΐ 球形. The catalyst is obtained from the Shendian two commercial dioxins as a carrier dissolved in pure water to make an aqueous solution.

Jr乂 Sodium will make the pH of the aqueous solution healthy at 7 and gradually drip into the ί not liquid. After several times of water washing, it will be dried at 1GG °c and changed to temperature, ~_. . . The reaction was carried out at a reaction temperature of 230 to 2, c: 5 -' optimum activity and hydrogen selectivity. _Inspection and fixation method 2 2 2 11 1293061 % The cerium oxide supported gold catalyst can achieve a methanol conversion rate of more than 85% at 290 〇C, a hydrogen selectivity of 87%, and no carbon monoxide production. The method disclosed in the invention prepares a cerium oxide-supporting gold catalyst with a gold crystal grain of less than 5 nm and more than 0.5 nm, which obviously oxidizes carbon monoxide for the partial oxidation reaction of sterol, so that there is no carbon monoxide in the hydrogen product. Pollution. The gold precursor is preferably prepared by adding O.Oi molar concentration to the gold chlorate aqueous solution. After the filtered filter cake is prepared, it is subjected to water washing at 70 ° C for more than five times to remove chlorine ions. [Embodiment] Example 1 Preparation of zirconia support gold catalyst

The present invention is a method for preparing a gold catalyst. The main steps include adding an aqueous solution of gold acid to the oxide support and adjusting the pH with an aqueous solution of sodium carbonate. At a value of 11 , gold oxide is produced on the surface of the catalyst, and the precursor of the catalyst is subjected to pretreatment such as washing, filtration, drying and calcination. The preparation steps of the ruthenium dioxide support gold catalyst are as follows: 1. Firstly weigh 5 grams of commercial dioxins (P-Gerre) and dissolve them in 4 cc of pure water. And first adjust the acidity of the suspension to a positive value of 7 with a sodium carbonate concentration of 50 cc; 2. In the suspension of the above step, add 0. 01 molar concentration (10) aqueous solution of gold acid acid, and 0.1 molar concentration of sodium carbonate maintains a pH equal to 7,

3. After the sedimentation hall is to be deposited, use the reducing device to filter the float liquid and obtain the miscellaneous, and wash it with 500cc of pure water of less than five times; 4. Place the cleaned_media_object in 1()()〇 c Dry in the oven for more than 24 hours to remove moisture; 5. Place the dried catalyst in a high temperature furnace at 4 Torr. The calcination is carried out under the underarm to prepare an oxidized fault-loaded gold catalyst having a calcination temperature of 4 〇〇 c. The TEM results are shown in Figure 1. f Example 2. Same as in Example 1, except that the calcination temperature in step 5 was changed to %. c calcining temperature of zirconia supported gold catalyst. The TEM results are shown in Figure 2. Example 1· Same as Example 1 ’Change only step 5 The calcination temperature was _〇c to prepare an oxidized knot-supporting gold catalyst having a 6〇〇〇c calcination temperature of 12 1293061 degrees. The gold grain size at 300-600 C calcination temperature is shown in Table 4. Table 4 Gold grain size at 300~600QC calcination temperature ' """"<~ Experiment _________ Calcination temperature (Qc) Gold grain size (nm) Example 2 300 3.4 Example 1 400 3.2 Comparative Example 1 600 3.8 Partial Oxidation of Methanol to Hydrogen This study used the partial oxidation of decyl alcohol as the activity test reaction for zirconia-supported gold catalyst. The whole system was analyzed under the appropriate temperature control and product analysis by gas chromatography. Catalyst activity test, the detailed steps are as follows: 1. Load the catalyst of Example 1 into the reaction tube; 2. Control the temperature of the reactor at 250 ° C; 3. Feed with sterol and oxygen. The oxygen/methanol feed molar ratio was 0.5, and the methanol partial oxidation reaction was carried out in the reaction bed; Comparative Example 2. Same as Example 3 except that the reaction temperature was changed to 230 QC. Paste Example 4. Same as Example 3 except that the reaction temperature was changed to 270 QC. Example 5. Same as Example 3 except that the reaction temperature was changed to 290 QC. The relationship between methanol conversion rate, hydrogen selectivity and reaction temperature is shown in Table 5, Figure 3 and Figure 4. 1293061 Table 5 Methanol conversion rate and hydrogen selectivity at 230-290 QC reaction temperature Experimental reaction temperature (°c) Sterol conversion rate (%) Helium selectivity (%). Comparative Example 2 230 15 20 Example 3 250 53 85 Example 4 270 65 84 Example 5 290 87 87

14 1293061 [Simple description of the diagram] Figure 1. Transmissive electron micrograph of Au/Zr02 catalyst calcined at 400 °C. Figure 2. Transmissive electrons of Au/Zr02 catalyst calcined at 300 °C. Micrograph Figure 3. Relationship between methanol conversion rate and reaction temperature of Au/Zr02 catalyst Figure 4. Relationship between argon gas selectivity and reaction temperature of Au/Zr02 catalyst [Key component symbol description]

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Claims (1)

1293061 Patent application scope: • / A kind of Lizaki storage body Jinlin silk high purity money process, gold catalyst direct control, less than 5 than G · 5 nanometers, and the shape of the spherical gold crystal The ruthenium feed oxygen/methanol molar ratio is 0.5, the reaction temperature is 23〇~29 (fc, reaction time ^ 10~190 minutes; the zirconia support gold catalyst is prepared by precipitation fixation method, Preparation ^ a · First take the commercial ceria carrier dissolved in pure water, stir evenly, and adjust the acidity of the suspension to 7 with sodium carbonate concentration of 〇丄 molar concentration; b · in step a In the suspension, a gold chlorate solution was added dropwise, and the pH was equal to 7 with sodium citrate at a molar concentration of 1; c. After the sedimentation was completed, the suspension was filtered to obtain a cake with a large amount of 7 〇〇. c pure water cleaning several times; d · after cleaning the catalyst seven trends 'in 1 〇〇〇 C for drying in the box for more than 24 hours to remove moisture; ^ e · after drying the catalyst precursors into the high temperature In the furnace, calcination is carried out at 300~6〇〇〇C. 2. The process of claim 1 is the uncalcined and calcined temperature. The degree is less than 600. 〇 3. For the process of the first application of the patent scope, the reaction temperature is from room temperature to 290 0 C. 4. The process of the first application of the patent scope, wherein the reaction time is more than 1 minute.