Preparation method for hollow molybdate composite microspheres and method for catalyzing ammonia borane hydrolysis to produce hydrogen

Abstract

A method of preparing hollow molybdate composite microspheres includes steps of: (1) dissolving 1-4 mmol of MCl.sub.2 in 20 ml of water to obtain a solution A and dissolving 1-4 mmol. of molybdic acid in 20 ml of water to obtain a solution B, followed by mixing the solution A and the solution B, in which M is Co, Ni, or Cu; (2) dissolving 10-40 mmol of urea in 40 ml of water, adding the mixed solution of step (1) and stirring uniformly; (3) placing the mixed solution of step (2) into a reaction vessel and reacting at 120-160° C. for 6-12 hours; (4) suction filtrating and water washing, followed by drying in a vacuum oven at 40-60° C.; (5) calcination at 350-500° C. for 2-4 hours in a Muffle furnace.

Claims

1. A method for preparing hollow molybdate composite microspheres, comprising steps of: (1) dissolving 1-4 mmol of MCl.sub.2 in 20 ml of water to obtain a solution A, and dissolving 1-4 mmol of molybdic acid in 20 ml of water to obtain a solution B, followed by mixing the solution A and the solution B to obtain a mixed solution C, in which M being at least one of Co, Ni, or Cu; (2) dissolving 10-40 mmol of urea in 40 ml of water, adding the mixed solution C of step (1) and stirring uniformly to obtain a solution D; (3) transferring the mixed solution D of step (2) into a reaction vessel and reacting at 120-160° C. for 6-12 hours to obtain product E; (4) carrying out suction filtration and water washing to the product E, followed by drying in a vacuum oven at 40-60° C. to obtain a solid; and (5) calcining the solid at 350-500° C. for 2 to 4 hours in a muffle furnace to obtain hollow molybdate composite microspheres.

2. The method for preparing the hollow molybdate composite microspheres according to claim 1, wherein a ratio of a total mass of soluble MCl.sub.2 to a mass of molybdic acid in the step (1) is 1:1.

3. The method for preparing the hollow molybdate composite microspheres according to claim 2, wherein in the step (2), a stirring time is 0.5-1 hour.

4. The method for preparing the hollow molybdate composite microspheres according to claim 3, wherein in the step (3), a temperature in the vacuum oven is 40-60° C.

5. The method for preparing the hollow molybdate composite microspheres according to claim 1, wherein in the step (2), a stirring time is 0.5-1 hour.

6. The method for preparing the hollow molybdate composite microspheres according to claim 5, wherein in the step (3), a temperature in the vacuum oven is 40-60° C.

7. The method for preparing the hollow molybdate composite microspheres according to claim 1, wherein in the step (3), a temperature in the vacuum oven is 40-60° C.

8. A method for catalyzing ammonia borane hydrolysis to produce hydrogen, wherein a catalyst used in the method is the hollow molybdate composite microspheres prepared by the method of claim 1.

9. A method for catalyzing ammonia borane hydrolysis to produce hydrogen, wherein a catalyst used in the method is the hollow molybdate composite microspheres prepared by the method of claim 2.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The foregoing and other exemplary purposes, aspects and advantages of the present invention will be better understood in principle from the following detailed description of one or more exemplary embodiments of the invention with reference to the drawings, in which:

(2) FIG. 1 is an SEM image of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention.

(3) FIG. 2 is a TEM image of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention.

(4) FIG. 3 is a BET test curve of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention.

(5) FIG. 4 is an XRD test curve of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention.

(6) FIG. 5 is a catalytic hydrogen production test curve of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(7) The invention will now be described in detail through several embodiments with reference to the accompanying drawings.

First Embodiment

(8) 1.1 mmol CuCl.sub.2 was dissolved in 20 mL water to obtain a solution A; 1 mmol molybdic acid was then dissolved in 20 mL water to obtain a solution B; and then the solution A and the solution B were mixed to obtain a mixed solution C.

(9) 2. 10 mmol urea was dissolved in 40 mL water, and the solution C above was added; the obtained solution was stirred for 30 min, then transferred to a reaction vessel and reacted at 160° C. for 8 hours, carried out with suction filtration and washing, and dried in a vacuum oven at 40° C., and calcined in a muffle furnace at 500° C. for 2 hours; the sample composition was CuMoO.sub.4.

Second Embodiment

(10) 1. x mmol CuCl.sub.2, y mmol NiCl.sub.2 and (1-x-y) mmol CoCl.sub.2 were dissolved in 20 mL water to obtain a solution A; 2 mmol molybdic acid was then dissolved in 20 mL water to obtain a solution B; and the two solutions were mixed to obtain a mixed solution C.

(11) 2. 20 mmol urea was dissolved in 40 mL water, and the solution C above was added; the obtained solution was stirred for 30 min, then transferred to a reaction vessel and reacted at 120° C. for 12 hours, carried out with suction filtration and washing, and dried in a vacuum oven at 60° C., and calcined in a muffle furnace at 500° C. for 2 hours; the sample composition was Cu.sub.xCo.sub.yNi.sub.1-x-yMoO.sub.4.

Third Embodiment

(12) 1. x mmol CuCl.sub.2, y mmol NiCl.sub.2 and (1-x-y) mmol CoCl.sub.2 were dissolved in 20 mL water to obtain a solution A; 2 mmol molybdic acid was then dissolved in 20 mL water to obtain a solution B; and the two solutions were mixed to obtain a mixed solution C.

(13) 2. 30 mmol urea was dissolved in 40 mL water, and the solution C above was added; the obtained solution was stirred for 30 min, then transferred to a reaction vessel and reacted at 160° C. for 8 hours, carried out with suction filtration and washing, and dried in a vacuum oven at 40° C., and calcined in a muffle furnace at 350° C. for 2 hours; the sample composition was Cu.sub.xCo.sub.yNi.sub.1-x-yMoO.sub.4.

Fourth Embodiment

(14) 1. x mmol CuCl.sub.2, y mmol NiCl.sub.2 and (1-x-y) mmol CoCl.sub.2 were dissolved in 20 mL water to obtain a solution A; 2 mmol molybdic acid was then dissolved in 20 mL water to obtain a solution B; and the two solutions were mixed to obtain a mixed solution C.

(15) 2. 40 mmol urea was dissolved in 40 mL water, and the solution C above was added; the obtained solution was stirred for 30 min, then transferred to a reaction vessel and reacted at 160° C. for 12 hours, carried out with suction filtration and washing, and dried in a vacuum oven at 40° C., and calcined in a muffle furnace at 500° C. for 4 hours; the sample composition was Cu.sub.xCo.sub.yNi.sub.1-x-yMoO.sub.4.

Fifth Embodiment

(16) 1. x mmol CuCl.sub.2, y mmol NiCl.sub.2 and (1-x-y) mmol CoCl.sub.2 were dissolved in 20 mL water to obtain a solution A; 4 mmol molybdic acid was then dissolved in 20 mL water to obtain a solution B; and the two solutions were mixed to obtain a mixed solution C.

(17) 2. 40 mmol urea was dissolved in 40 mL water, and the solution C above was added; the obtained solution was stirred for 1 hour, then transferred to a reaction vessel and reacted at 160° C. for 12 h, carried out with suction filtration and washing, and dried in a vacuum oven at 60° C., and calcined in a muffle furnace at 500° C. for 4 hour; the sample composition was Cu.sub.xCo.sub.yNi.sub.1-x-yMoO.sub.4.

(18) 1. SEM Analysis

(19) FIG. 1 is an SEM image of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention. As can be seen from the scan diagram, the morphology of Co.sub.0.8Cu.sub.0.2MoO.sub.4 obtained by hydrothermal synthesis is nanowires with a diameter of about 0.5-0.8 μm.

(20) 2. TEM Test

(21) For the TEM images of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention, the catalyst performance of the hollow microspheres can be further confirmed from the projection view.

(22) 3. BET Test

(23) FIG. 3 is a nitrogen adsorption and desorption isotherm curve of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention, having a specific surface area of 30.01 m.sup.2/g.

(24) 4. XRD

(25) FIG. 4 is an XRD test of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention; the characteristic peaks of corresponding crystal planes of CuMoO.sub.4 and CoMoO.sub.4 are marked in the figure.

(26) 5. Test of Catalytic Performance for Hydrogen Production

(27) FIG. 5 is a performance test of Co.sub.0.8Cu.sub.0.2MoO.sub.4 prepared according to the present invention as a catalyst for ammonia borane hydrolysis to produce hydrogen, the amount of NH.sub.3BH.sub.3 is 3 mmol, NaOH is 20 mmol, and the catalyst is 10 mg. The test showed that that it produced 56 mL hydrogen per minute by taking Co.sub.0.8Cu.sub.0.2MoO.sub.4 as a catalyst at 25° C.

(28) While the invention has been described in terms of several exemplary embodiments, those skilled on the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims. In addition, it is noted that, the Applicant's intent is to encompass equivalents of all claim elements, even if amended later during prosecution.