CN101007271A - Preparation method of oxygen-producing photocatalyst of composite oxides - Google Patents

Abstract

A preparation method of oxide photochemical catalyst prepared by composite oxide belongs to visible light catalysis field. The preparation process is: it dissolves bismuth nitrate containing crystal water into 2-2.5M nitrate, the mass concentration of bismuth nitrate is 7.4%--29.5%; dissolves metavanadate ammonium into 40-50DEG C hot water, the mass concentration of metavanadate ammonium is 1.8%-7.1%; mixes said two solution and adds surface activator into it, stirs it uniformly and adjusts it with aqua forties until the pH is 0-2; heats it in press-still and maintains temperature of 190-260DEG C, the reaction time is 30-50 hours; then cools it and sucks it, washes repeatedly with deionized water until the solution is colorless and clear, dries it. The preparation precess avoids using acute-toxic vanadic anhydride powder and precipitant, and no acute-toxic intermediate product is generated; the active of oxygen prepared by ultraviolet light and using the oxide photochemical catalyst can reach 40-90umol/h and the active of oxygen catalyzed by visible light is 70-355umol/h.

Description

A kind of preparation method of oxygen-producing photocatalyst of composite oxides

Technical field

The present invention relates to a kind of preparation method of oxygen-producing photocatalyst of composite oxides, belong to the visible light catalytic field

Background technology

Pucherite comprises three kinds of crystal structures, cubic scheelite-type structure, cubic zircon structure and the monocline scheelite-type structure with photocatalytic activity.The pucherite of traditional monocline scheelite-type structure is that high-temperature heat treatment or frit reaction are prepared behind adding acetone or the alcohol mechanical ball milling with oxidation bismuth meal mixing vanadium pentoxide powder, and reaction temperature is more than 300 ℃.This conventional method technological process is simple, is violent in toxicity but the weak point of this method is a vanadic anhydride, and is very big to the human injury; The pucherite crystalline structure of solid-phase sintering preparation is wayward, reduces catalytic effect; And the preparation process energy consumption is very big, and produces noise and dust pollution.

Summary of the invention

The object of the present invention is to provide a kind of preparation method of oxygen-producing photocatalyst of composite oxides, this method technology is simple, and operation is easily gone, and is nontoxic, with low cost and environmental friendliness.

The preparation method of a kind of oxygen-producing photocatalyst of composite oxides provided by the invention is characterized in that, may further comprise the steps:

1) will contain the bismuth nitrate of the crystallization water, and be dissolved in the nitric acid of 2-2.5M, the bismuth nitrate mass concentration is 7.4%--29.5%; Ammonium metavanadate is dissolved in 40--50 ℃ the hot water, the ammonium metavanadate mass concentration is 1.8%-7.1%;

2) mix above-mentioned two kinds of solution, add surfactant, stir and regulate pH to 0-2 with nitric acid;

3) pressing heating steps 2 in the still certainly) solution of preparation, keep 190-260 ℃ of temperature, the reaction time is 30-50 hour, suction filtration after the cooling is colourless to clear liquid with the deionized water cyclic washing, oven dry.

Described surfactant is a lauryl sodium sulfate, dodecyl sodium sulfate a kind of.

The present invention has following effect:

1 preparation process needn't be carried out high-temperature heat treatment more than 300 ℃, and course of reaction needn't add precipitating reagent, and the crystalline form homogeneous of the catalyst that the adding surfactant makes is pure monocline scheelite-type structure BiVO ₄, pattern is spherical and octahedra shape, increased the catalytic activity that photodissociation water is produced oxygen.

2 adopt eco-friendly hydrothermal synthesis method, have avoided the adverse effect of using traditional solid phase method powder ball milling generation dust and noise that environment is caused.

The powder constituent composition that one step of 3 hydro-thermals synthesizes meets theory of computation value, and the process that this method prepares catalyst is simple, and energy consumption is low, has reduced the catalyst cost of manufacture.

Description of drawings

Fig. 1 for the present invention at 190 ℃, the catalyst sem photograph that hydro-thermal reaction made in 50 hours

Fig. 2 for the present invention at 220 ℃, the catalyst sem photograph that hydro-thermal reaction made in 40 hours

Fig. 3 for the present invention at 260 ℃, the catalyst sem photograph that hydro-thermal reaction made in 30 hours

Fig. 4 is the Electronic Speculum figure of Fig. 3 after amplifying

Fig. 5 for the present invention at 260 ℃, catalyst XRD that hydro-thermal reaction made in 30 hours spectrum

Fig. 6 for the present invention at 190 ℃, the catalyst transmission electron microscope picture that hydro-thermal reaction made in 50 hours

Fig. 7 for the present invention at 190 ℃, hydro-thermal reaction made the electron diffraction diagram of catalyst in 50 hours

The specific embodiment

Also in conjunction with the accompanying drawings the present invention is described in detail below by embodiment, wherein:

Embodiment 1: the 3.69g bismuth nitrate is dissolved in the nitric acid that 50ml concentration is 2M, the 0.89g ammonium metavanadate is dissolved in 40 ℃ of water of 50ml, mix, add lauryl sodium sulfate 0.06g, stir, regulate pH=0 with nitric acid.Solution is changed over to from pressing in the still, 190 ℃ of reactions 50 hours, cooling, suction filtration, washing, dry (corresponding ESEM Fig. 1, transmission electron microscope Fig. 6 and electronic diffraction Fig. 7), the speed of the monocline scheelite pucherite catalyst of preparing catalytic decomposition water system oxygen under 300 watts of mercury lamps (wave-length coverage 300-380 nanometer) and three hectowatt xenon lamps (wavelength is greater than 420 nanometers) irradiation detects with Agilent 4890D gas-chromatography, finally goes out the system oxygen productive rate of catalyst according to calculated by peak area.Ultraviolet catalytic system oxygen productive rate is 50umol/h, and visible light catalytic system oxygen productive rate is 70umol/h.

Embodiment 2: the 7.37g bismuth nitrate is dissolved in the nitric acid that 50ml concentration is 2.5M, the 1.78g ammonium metavanadate is dissolved in 45 ℃ of water of 50ml, mix, add dodecyl sodium sulfate 0.13g, stir, regulate pH=1 with nitric acid; Solution is changed over to from pressing in the still, in 220 ℃ of reactions 40 hours, cooling, suction filtration, washing, drying.(corresponding ESEM Fig. 2), the photocatalysis method of testing is with embodiment 1, and ultraviolet catalytic system oxygen productive rate is 40umol/h, and visible light catalytic system oxygen productive rate is 140umol/h.

Embodiment 3: the 14.74g bismuth nitrate is dissolved in the nitric acid that 50ml concentration is 2.5M, the 3.56g ammonium metavanadate is dissolved in 50 ℃ of hot water of 50ml, mixes, add lauryl sodium sulfate 0.24g, stir, regulate pH=2 with nitric acid, solution is changed over to from pressing in the still, 260 ℃ of reactions 30 hours, cooling, suction filtration, washing, drying.(corresponding XRD figure 5, and ESEM Fig. 3 and Fig. 4), photocatalysis method of testing are with embodiment 1, and ultraviolet catalytic system oxygen productive rate is 90umol/h, and visible light catalytic photocatalysis system oxygen productive rate is 355umol/h.

The synthetic photochemical catalyst of existing hydro-thermal is produced the active 30-40umol/h of oxygen under the ultraviolet catalytic, produce the active 60-70umol/h of oxygen under the visible light catalytic.The present invention has increased the catalytic activity that photodissociation water is produced oxygen.

Claims (2)

1, a kind of preparation method of oxygen-producing photocatalyst of composite oxides is characterized in that, may further comprise the steps:

1) will contain the bismuth nitrate of the crystallization water, and be dissolved in the nitric acid of 2-2.5M, the bismuth nitrate mass concentration is 7.4%-29.5%; Ammonium metavanadate is dissolved in 40-50 ℃ the hot water, the ammonium metavanadate mass concentration is 1.8%-7.1%;

2) mix above-mentioned two kinds of solution, add surfactant, stir and with the nitre acid for adjusting pH value to 0-2;

3) pressing heating steps 2 in the still certainly) solution of preparation, keep 190-260 ℃ of temperature, the reaction time is 30-50 hour, suction filtration after the cooling is colourless to clear liquid with the deionized water cyclic washing, oven dry.

2, preparation method according to claim 1 is characterized in that, described surfactant is a lauryl sodium sulfate, one of dodecyl sodium sulfate.

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