CN102677093A - Lead dioxide powder porous electrode and preparation method thereof - Google Patents

Abstract

The invention discloses a lead dioxide powder porous electrode and a preparation method thereof. The lead dioxide powder porous electrode comprises following raw materials by mass percent: 57.5-82.5 percent of beta-PbO2 powder, 2.5-15 percent of graphite, 2.5-15 percent of activated carbon and the balance of binder, wherein the binder is a polytetrafluoroethylene emulsion with a mass concentration of 60 percent; and the addition volume of the binder is calculated by solute. The preparation method of the lead dioxide powder porous electrode comprises unit processes of material mixing, drying and compression molding, wherein the material mixing process comprises the step of adding the graphite and the activated carbon to the substrate beta-PbO2 powder to act as doping materials; and the addition volumes of the graphite and the activated carbon are equal. The beta-PbO2 powder porous electrode prepared by using the method has the advantages of good electrical conductivity, strong electrical catalytic activity and long service life, so the deficiency of a method for preparing the electrode by using an electro-deposition method is radically remedied.

Description

A kind of lead dioxide powder porous electrode and preparation method thereof

One, technical field

Present method relates to lead dioxide electrode and preparation method thereof, exactly is that a kind of graphite and gac of adopting carries out lead dioxide powder porous electrode of doping vario-property and preparation method thereof.

Two, background technology

Plumbic oxide (PbO ₂) electrode has the overpotential for oxygen evolution height in the aqueous solution, to characteristic such as the electrocatalysis degrading activity of organic pollutant is strong; Be a kind of good electrocatalysis material, successfully be applied in many inorganic and aspects such as organic cpds electrolysis production, environmental pollution control at present.

Electrodip process is adopted in the preparation of lead dioxide electrode at present more, and deposited film has two kinds on α and β type, β-PbO ₂Electroconductibility, erosion resistance be superior to α-PbO ₂So, often adopt β-PbO ₂Prepare oxidizing electrode, and α-PbO ₂Often be used as the middle layer and be plated on earlier on the matrix to suppress passivation, electrodip process prepares PbO ₂The greatest problem that electrode exists is that coating comes off.Chinese scholars is being carried out persevering research at selection, counter electrode doping vario-property, the new preparation method aspects such as (as being coated with cream method, high compression moulding sheet method) of invention of base material at present.

Three, summary of the invention

The present invention aims to provide a kind of lead dioxide powder porous electrode and preparation method thereof, and the electrode of preparation is β-PbO ₂Electrode fundamentally solves coating β-PbO ₂The complicated difficult control of the electroplating technology of electrode, problem such as be prone to come off, and improved β-PbO ₂The electro catalytic activity of electrode.

Technical solution problem of the present invention adopts following technical scheme:

Lead dioxide powder porous electrode of the present invention is characterized in that its raw material constitutes by mass percentage:

β-PbO ₂Powder 57.5-82.5%, graphite 2.5-15%, gac 2.5-15%, surplus is a sticker;

Said sticker is the ptfe emulsion of mass concentration 60%, and the addition of sticker is in solute.

The addition of graphite is preferably 7.5-10%, and the addition of gac is preferably 7.5-10%, and the ratio of the quality that both add is 1:1.

The preparation method of lead dioxide powder porous electrode of the present invention comprises each unit process of batch mixing, drying and compression molding, it is characterized in that: said batch mixing is to electrode matrix β-PbO ₂Add graphite and gac in the powder as dopant material, the addition of graphite and gac equates.

Specifically operation according to the following steps:

With β-PbO ₂Powder, graphite, gac and sticker mix, and obtain compound after stirring; With said compound in 70-90 ℃ of dry 20-40min, with after compression molding obtains PbO ₂Powder porous electrode.

Because PbO ₂Belong to semi-conductor, therefore an amount of adding graphite can improve the electroconductibility (as shown in Figure 2) of electrode, thereby makes electrode produce higher current responsivity, can reduce groove on the other hand and press and energy consumption, reduces running cost.And gac can strengthen PbO owing to have the good adsorption characteristic ₂The active site of electrode surface can produce the molecule or the ion of strong oxidation more in absorb polluted matter and the solution, so efficient hardening the electrocatalytic oxidation property of electrode.Therefore in electrode, add gac and can realize the coupling of enrichment-catalysis-oxidation kinds of processes technology.

Beneficial effect of the present invention is embodied in:

1, the present invention adds the electroconductibility that an amount of graphite has effectively improved electrode, has reduced the running cost of device;

2, the present invention's proper amount of active carbon of mixing has strengthened the active site of electrode surface, efficient hardening the electrocatalytic oxidation property of electrode;

3, the inventive method is compared with traditional electrodip process, and simple to operate, processing condition are easy to control;

4, the β-PbO of the inventive method preparation ₂Powder porous electrode has advantages such as good conductivity, electro catalytic activity is strong, the life-span is long, fundamentally remedied the deficiency that electrodip process prepares electrode.

Four, description of drawings

Fig. 1 is β-PbO that the present invention prepares ₂The XRD figure spectrum and the standard diagram (a) thereof of powder (b).

Fig. 2 is pure β-PbO ₂β-the PbO of electrode and the present invention's preparation ₂The cyclic voltammetry curve of powder porous electrode.Can find out from Fig. 2, at these two kinds of electrode surfaces the direct oxidation effect not take place, the removal of ammonia nitrogen is to realize through the strong oxidation of the OH that produces, at the very strong PbO of catalytic activity ₂Add suitable amount of graphite and gac in the electrode, make electrode have porousness, process powder porous electrode, conductivity that on the one hand can intensifier electrode, gac has adsorption on the other hand, can strengthen PbO ₂The active site of electrode surface can produce the molecule or the ion (like OH) of strong oxidation in the more adsorbent solution, and then help the catalytic oxidation of electrode.

Fig. 3 is pure β-PbO ₂β-the PbO of electrode and the present invention's preparation ₂Powder porous electrode electricity catalyzed oxidation ammonia nitrogen comparison diagram.Can find out from Fig. 3, at PbO ₂Mix a certain amount of mixed powder (graphite+gac, mass ratio are 1:1) in the powder, made PbO ₂The catalytic performance of powder porous electrode is significantly increased, and effect was best when wherein the addition of mixed powder was 15-20%.

Five, practical implementation instance

1, β-PbO ₂The preparation of powder: 10gPb (Ac) 2 is dissolved in the 20mL water, regulates pH at 9.0-10.0 with NaOH, dissolving back fully adds 80mLNaClO and stirs.Behind reaction 6h about 90 ℃, the gained deposition promptly obtains dark-brown β-PbO after filtration, washing and drying ₂Powder.Its XRD test collection of illustrative plates and standard diagram complete corresponding (as shown in Figure 1).

2, β-PbO ₂The preparation of powder porous electrode

Take by weighing the β-PbO of certain mass ₂Powder; Mix the graphite+gac mixed powder (both mass ratioes are 1:1) of certain mass and the bonding agent (ptfe emulsion of mass concentration 60%) of certain mass therein respectively; Mix the back in 80 ℃ of dry 30min, obtain PbO through mold pressing (under 20MPa, keeping 2min) ₂Powder porous electrode.

β-PbO ₂The mass percent of powder, graphite+gac mixed powder and ptfe emulsion tackiness agent is as follows:

β-PbO 2Powder

Graphite+gac mixed powder

The tetrafluoroethylene tackiness agent

		(both mass ratioes are 1:1)	(the shared per-cent of solute)
				Embodiment 1	82.5%	5%	12.5%
Embodiment 2	77.5%	10%	12.5%
				Embodiment 3	72.5%	15%	12.5%
Embodiment 4	67.5%	20%	12.5%
				Embodiment 5	62.5%	25%	12.5%
Embodiment 6	57.5%	30%	12.5%

3, electrode electricity catalytic activity experiment

With the ammonia nitrogen simulated wastewater is process object, investigates prepared β-PbO ₂Powder porous electrode and pure β-PbO ₂The electro catalytic activity of electrode.Experiment condition is current density 40mA/cm ², ammonia nitrogen starting point concentration 50mg/L, pH are 5.6, supporting electrolyte is 0.05mol/LNa ₂SO ₄, the result sees Fig. 3.

Can find out from Fig. 3, at PbO ₂Mix a certain amount of mixed powder (graphite+gac, mass ratio are 1:1) in the powder, made PbO ₂The catalytic performance of powder porous electrode is significantly increased.

Claims (4)

1. lead dioxide powder porous electrode is characterized in that its raw material constitutes by mass percentage:

β-PbO ₂Powder 57.5-82.5%, graphite 2.5-15%, gac 2.5-15%, surplus is a sticker;

Said sticker is the ptfe emulsion of mass concentration 60%, and the addition of sticker is in solute.

2. lead dioxide powder porous electrode according to claim 1 is characterized in that: the addition of graphite is 7.5-10%, and the addition of gac is 7.5-10%.

3. the preparation method of the described lead dioxide powder porous electrode of claim 1 comprises each unit process of batch mixing, drying and compression molding, it is characterized in that: said batch mixing is to electrode matrix β-PbO ₂Add graphite and gac in the powder as dopant material, the addition of graphite and gac equates.

4. preparation method according to claim 3 is characterized in that operating according to the following steps:

With β-PbO ₂Powder, graphite, gac and sticker mix, and obtain compound after stirring; With said compound in 70-90 ℃ of dry 20-40min, with after compression molding obtains PbO ₂Powder porous electrode.

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