CN102962059A

CN102962059A - Method for preparing noble bimetal nano catalyst granules

Info

Publication number: CN102962059A
Application number: CN2011102582075A
Authority: CN
Inventors: 周有福; 洪茂椿; 江飞龙
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Fujian Institute of Research on the Structure of Matter of CAS
Priority date: 2011-09-01
Filing date: 2011-09-01
Publication date: 2013-03-13

Abstract

The invention provides a method for preparing noble bimetal nano catalyst granules. According to the invention, the noble bimetal nano catalyst granules can be taken as a catalyst, sodium halide is taken as a mineralizer, polyvinylpyrrolidone (PVC) is taken as a reducing agent; noble bimetal ions can be subjected to a reduction reaction under hydrothermal condition to generate noble bimetal nano catalyst granules. The method of the invention is an aqueous phase reaction, the process is simple, the prepared noble bimetal nano catalyst granules are in a crystalline state, the purity is high and the dispersity is good.

Description

The preparation method of a kind of pair of noble metal nano catalyst granules

Technical field

The invention belongs to field of fine chemical, especially relate to the preparation of two noble metal nano catalyst granules.

Background technology

Noble metal nano particles is widely used in petrochemical industry, fine chemistry industry and biochemical field for the preparation of nanocatalyst, as being used for the Pd/Al of selective hydrogenation ₂O ₃Catalyst, be used for isomerization reaction the Pt/ molecular sieve catalyst, be used for the Ag/Au catalyst of oxidation reaction.Its crystallite dimension is less than 100 nanometers, and the atom that is positioned at crystal boundary and surface in the crystal grain has accounted for sizable ratio, has the characteristics such as bigger serface, high surface energy, shows good catalytic activity and catalytic selectivity.Duplex metal nano granule can change the catalytic activity of monometallic nano particle, selective and anti-inactivation, can reduce the consumption of expensive metal simultaneously.In the catalyst preparation science, the preparation of two noble metal nano catalyst granules has obtained more concerns of people.

Researcher been has has been researched and developed the different preparation methods of relevant noble metal nano particles both at home and abroad.Under inert atmosphere, hydrogen reducing metal platinum ion obtains monodispersed Pt nanoparticle colloidal solution such as people such as U.S. M. A. El-Sayed; The people such as U.S. Y.N. Xia adopt the method for nucleus control growth, take nanoparticle palladium as nucleus, are aided with surfactant PVP, reduce platinum ion with ascorbic acid, preparation platinum palladium nano-particles; The people such as Japan Hirai reflux by alcohol-water, and the reducing metal precursor methods makes the precious metal colloid of stabilizing polymer; The people such as South Korea S.W. Han have prepared tree-shaped porpezite nano particle by hydrazine reduction palladium, gold ion in the presence of surfactant PVP.The people such as Tsing-Hua University's Li Yadong will be take octadecylamine as solvent and reducing agent, and solvent-thermal method makes golden nano nickel particles; Cui of Qingtao Chemical Engineering College makes Lin Dengren in vacuum chamber, by high arc temperature evaporation nickel and palladium, obtains the Ni-Pd alloy nanocatalyst through Collision deposition.There is the potentially contaminated problem in the employing organic solvent that these methods have; What have also needs inert atmosphere or vacuum environment, and equipment requirement is high; The technique that has is complicated, and applicable surface is narrow.Therefore, develop a kind of aqueous phase reactions, simple, the widely applicable duplex metal nano granule preparation method of technique has important using value.

Summary of the invention

The purpose of this invention is to provide the method that a kind of hydro-thermal method prepares the high-quality duplex metal nano granule.The present invention adopts following technical scheme:

1, the present invention prepares two noble metal nano particles, take sodium halide as mineralizer, polyvinylpyrrolidone (PVP) is reducing agent, and two metal ion species react under hydrothermal condition and generate duplex metal nano granule, the described pair of noble metal be platinum, palladium, gold, silver wherein two.

2, the respective metal ion is selected the pure inorganic salts of the analysis that is easy to get, such as palladium bichloride, potassium chloroplatinite, gold chloride, silver nitrate.The pure sodium bromide of the optional analysis of sodium halide, sodium fluoride etc., PVP is AR, average molecular weight range is 8000-40000.The concentration of above-mentioned three kinds of reactants should be controlled at certain limit, and the excessive concentration powder produces reunion easily, and it is low that concentration is crossed low-yield.

3, the temperature of hydro-thermal reaction is controlled in 120-200 degree centigrade, and the reaction time was controlled in 1-20 hour, and temperature-rise period and temperature-fall period can be controlled in 1-10 hour.

4, reaction finishes, and the nano particle of generation can by centrifugation, be removed upper solution, respectively wash once with deionized water washing and absolute ethyl alcohol again, be reactant and the impurity that does not act in order to remove, organic solvent washing is in order to reduce reunion, to accelerate the drying of particle.

Compared with prior art, the present invention has following advantage: aqueous phase reactions, technique are simple, widely applicable, and two noble metal nano particles of preparation are high, the good dispersion degree of crystalline state, purity.

Description of drawings

Fig. 1 is that average grain diameter is the EDS spectrogram of the platinum palladium bimetal granule of 10.1 nm; State 2 is the powder x-ray diffraction figure of the platinum palladium bimetal granule of 10.1 nm for average grain diameter; Fig. 3 is that average grain diameter is the transmission electron microscope picture of the platinum palladium bimetal granule of 10.1 nm; Fig. 4 is that average grain diameter is the transmission electron microscope picture of the porpezite bimetal granule of 7.2 nm.

The specific embodiment

Example 1: 5.0 mg palladium bichlorides, 10.0 mg potassium chloroplatinites, 50.0 mg sodium bromides, 60.0 mg polyvinylpyrrolidones (MW 8000) are dissolved in the 15.0 ml deionized waters, stir, place the withstand voltage reactor of stainless steel of 40ml, 180 ℃ the reaction 10 hours after, the gained precipitation is through centrifugation, with deionized water and absolute ethanol washing, obtain black powder after the drying.Fig. 1 is the EDS spectrogram, as can be known its platiniferous, two kinds of elements of palladium; State 2 is powder x-ray diffraction figure, and it is pure face-centered cubic phase platinum palladium bimetallic as can be known; Fig. 3 is transmission electron microscope picture, and it is the nano particle of good dispersion degree as can be known, and average grain diameter (major axis) is 10.1nm.

Example 2: 5.0 mg palladium bichlorides, 5.0 mg gold chlorides, 50.0 mg sodium bromides, 60.0 mg polyvinylpyrrolidones (MW 8000) are dissolved in the 15.0 ml deionized waters, stir, place the withstand voltage reactor of stainless steel of 40ml, 160 ℃ the reaction 10 hours after, the gained precipitation is through centrifugation, with deionized water and absolute ethanol washing, obtain black powder after the drying.Fig. 4 is transmission electron microscope picture, and it is the porpezite nano particle of good dispersion degree as can be known, and average grain diameter is 7.2 nm.

Example 3: 10.0 mg potassium chloroplatinites, 5.0 mg gold chlorides, 50.0 mg sodium bromides, 30.0 mg polyvinylpyrrolidones (MW 8000) are dissolved in the 15.0 ml deionized waters, stir, place the withstand voltage reactor of stainless steel of 40ml, 180 ℃ the reaction 15 hours after, the gained precipitation with deionized water and absolute ethanol washing, obtains black powder through centrifugation after the drying, it is the nano platinum particle of good dispersion degree, and average grain diameter is 17.4 nm.

Claims

1. the preparation method of two noble metal nano catalyst granules, take sodium halide as mineralizer, take polyvinylpyrrolidone as reducing agent, two kinds of precious metal ions reduction reaction under hydrothermal condition generates duplex metal nano granule, the described pair of noble metal be platinum, palladium, gold, silver wherein two.

2. preparation method according to claim 1 is characterized in that, the pure inorganic salts of precious metal ion Analysis about Selection are such as palladium bichloride, potassium chloroplatinite, gold chloride, silver nitrate.

3. preparation method according to claim 1 is characterized in that, sodium halide is for analyzing pure sodium bromide, sodium fluoride etc.

4. preparation method according to claim 1 is characterized in that, polyvinylpyrrolidone is AR, and molecular weight is at 8000-40000.

5. preparation method according to claim 1 is characterized in that, the temperature of hydro-thermal reaction is controlled in 120-200 degree centigrade, and the reaction time was controlled in 1-20 hour.