CN101654790A - Preparation method of neodymium-doped titanium base tin dioxide-antimony electrode - Google Patents

Abstract

The invention relates to a preparation method of neodymium-doped titanium base tin dioxide-antimony electrode. The method comprises the following steps: 1) the pretreatment of electrode substrate: polishing, alkaline cleaning and pickling; 2) the preparation of masking liquid: dissolving SnCl4.5H2O, SbCl3 and Nd(NO3)3 according to a ratio of 100:15:1 in solvent to obtain the masking liquid; 3) thepreparation of electrode coating by using immersion method: (1) completely soaking the titanium electrode substrate in the masking liquid for 1min; (2) withdrawing the titanium electrode substrate, blowing away the excessive masking liquid with a blow drier; (3) drying in a baking oven at 100-120 DEG C for 10min to volatilize all the solvent; (4) placing the substrate in a muffle furnace to perform thermal oxidation at 550 DEG C for 15min; (5) cooling to room temperature, dipping again, drying, performing thermal oxidation and repeating the above steps for 15 times to obtain the Nb-doped Ti/Sb-SnO2 electrode. The Nb-doped Ti/Sb-SnO2 electrode prepared by the method of the invention has high oxygen evolution potential, catalytic performance and electricity.

Description

The preparation method of neodymium-doped titanium base tindioxide-antimony electrode

Technical field:

The present invention relates to a kind of neodymium-doped titanium base tindioxide-antimony (Ti/Sb-SnO ₂) preparation method of electrode, belong to the electrocatalysis water-treatment technology field.

Background technology:

Current society, the pollutant kind that the mankind are discharged in the water body is increasing, and composition is also increasingly sophisticated, the organic discharging of especially a large amount of poisonous and bio-refractories, more traditional wastewater processing technology has brought greatest challenge.People press for that new good reliability, the cost of exploitation is low, the sewage purification treatment technology of high efficiency.

The electrocatalysis technology is a kind of processing mode that has much the cleaning of potentiality, contrasts existing physics, chemistry and biologic treating technique, and it has the advantage of many uniquenesses:

1 is of many uses.The electrochemical treatment technology, not only can utilize methods such as direct oxidation, indirect oxidation, electroreduction, electro-adsorption that waste water is handled, can also be used to suspend or being separated of colloidal dispersion, as electric flotation separation etc., can also in drinking water purification, play the effect of virus killing sterilization etc., all can play a role at aspects such as sewage, waste gas, Toxic waste processing.

2. applied widely.Electrochemical techniques all have treatment effect preferably to multiple pollutent, both can individual curing, can be used as pre-treatment again, and improve the bio-degradable of waste water, also can be used as the aftertreatment of electrochemical disinfection simultaneously.

3. be easy to measure and control.Main operating parameter in the electrochemistry operational process is electric current and current potential, and therefore, its controllable degree easily is automated than higher, can effectively save handling cost.

4. equipment is simple, and the operation and maintenance expense is lower.

The conducting metal oxide electrode has important electric catalyticing characteristic, and this class electrode mostly is semiconductor material greatly, and in fact the research of this class material character is set up based on semiconductor material.For environment electrochemistry, this type of electrode be used for aspects such as environmental pollutant removal, fuel cell, organic electrosynthesis most important, also be the electro catalytic electrode of tool development prospect.The ti-based coating electrode is the principal mode of metal oxide electrode, and it has overcome the shortcoming that conventional graphite electrode, platinum electrode, lead dioxide electrode etc. exist, for the preparation of electro catalytic electrode provides new approaches.And the doping of rare earth can change the oxygen evolution potential of electrode, and all there are significant effects in the catalytic performance of counter electrode, conductivity and life-span etc.

With the titanium net is matrix, adopts the Nd doped Ti/Sb-SnO of immersion process for preparing ₂Electrode, be a kind ofly can effectively remove difficult degradation in the water body, toxic organic compound, improve the novel electrode of the biodegradability of pollutent, it not only has common electrolysis anodic advantage, low as cost, applied widely, non-secondary pollution etc., have more the unexistent oxygen evolution potential of ordinary electrode, high catalytic property, high conductivity and long advantages such as work-ing life, it has solved the problem that traditional wastewater treating technology is difficult to administer refractory organic or bio-toxicity pollutent effectively, it is a kind of good reliability, cost is low, high efficiency, the environment amenable green technology of administering is for the practical application of electrochemical method provides certain theoretical guidance.

Summary of the invention:

For overcoming the deficiencies in the prior art, the invention provides a kind of oxygen evolution potential that has, the rare earth neodymium doped Ti/Sb-SnO of high catalytic performance and high conduction performance ₂The preparation method of electrode.

A kind of neodymium doped Ti/Sb-SnO ₂The preparation method of electrode, its preparation method is as follows:

1) electrode matrix pre-treatment

The titanium silk specification of electrode matrix titanium net is 1.5mm * 1.0mm, diamond mesh size 3mm * 8mm, and pretreatment process is:

(1) polishing

At first adopt mechanical polishing, remove electrode matrix oxide on surface and dirt, use 600 order sand papering corners again, make it slick and sly, rinse well with deionized water at last;

(2) alkali cleaning

It is 5% yellow soda ash (Na that entire electrode is immersed in mass concentration ₂CO ₃) in the washing lotion, keep each pole piece to be in separate stage, be heated to boiling, keep 1h, stop heating, cooling is rinsed well with deionized water;

(3) pickling

It is in 10% the oxalic acid washing lotion that entire electrode is immersed in mass concentration, and boiling state is handled 2-3h down, behind the deionized water rinsing surface impurity, puts into mass concentration and is 95% ethanol and preserve;

2) masking liquid preparation

With crystallization tin tetrachloride, butter of antimony and neodymium nitrate ratio in 100: 15: 1, be dissolved in the solvent, make masking liquid;

3) coating preparation

Adopt the immersion process for preparing electrode coating, concrete preparation method is:

(1) titanium electrode substrate is fully immersed in the masking liquid, keeps 1min;

(2) take out titanium electrode substrate, blow away unnecessary masking liquid with hair dryer;

(3) in 100-120 ℃ of baking oven, dry 10min, solvent is all volatilized;

(4) put into retort furnace, thermooxidizing 15min under 550 ℃ of environment;

(5) be cooled to room temperature, repeating step (1) is to (4), i.e. immersion, dry, thermooxidizing repeat 15 times, obtain neodymium-doped titanium base tindioxide-antimony electrode.

Adopt aforesaid method, prepare a neodymium doped Ti/Sb-SnO respectively ₂In an electrode and the barren reference electrode (step 2), Nd content is 0, and all the other are all consistent).Scan by electrokinetic potential, SEM etc., its structure, oxygen evolution potential are analyzed, measuring its ultimate life with damaged method, is anode with Nd doped Ti/Sb-SnO2 electrode again, is negative electrode with the titanium plate, delivery is intended waste water from dyestuff 200ml in electrolyzer, wherein reactive brilliant red x-3b concentration is 100mg/L, carries out wastewater treatment research, and then contrasts its catalytic performance.

1, the SEM photo of electrode

Fig. 1 a is the SEM photo of blank electrode.Blank electrode surface is very inhomogeneous, uneven, and a lot of staggered cracks are arranged, and the slit is bigger, and crystalline particle is arranged, and the electrode erosion resistance is bad, and coating comes off easily.Too much crack certainly will be quickened the titanium matrix and is oxidized to TiO ₂Process, this has just reduced the bonding force between coating and matrix, the souring of the gas that electrolysis simultaneously produces makes that also coating comes off easily.

Fig. 1 b is rare earth Nd doped Ti/Sb-SnO ₂The SEM photo of electrode.Tangible change has taken place rear-earth-doped rear electrode pattern: electrode crystal grain distributes more even, and crystal grain is grown fuller, and the concave-convex sense of electrode surface obviously diminishes, and the slit narrows down, and crystalline particle reduces, and electrode surface does not have thick crackle, and outward appearance is evenly fine and close.This illustrates that an amount of Nd doping can improve Ti/Sb-SnO ₂The pattern of electrode coating stops the diffusion of oxygen to matrix, reduces TiO ₂The formation of insulation layer reduces interface resistance.

2, the electrokinetic potential of electrode test

Fig. 2 is the electrokinetic potential scanning curve figure of blank electrode and rare earth Nd doped Ti/Sb-SnO2 electrode.As seen from the figure, the electrokinetic potential scanning curve shape of each electrode is similar substantially, is being the straight line parallel with X-coordinate before-1.5V-1.5V, and ordinate value is 0, illustrates at this moment all not react on each electrode reactionless electric current; And after 1.5V, the curve of each electrode successively upwarps rapidly, and at this moment the current density fast rise begins the aerobic air elutriation and go out.The supporting electrolyte of this phenomenon and employing is inertia Na ₂SO ₄Conform to.Simultaneously, we can see that blank electrode early start analyses oxygen, and oxygen evolution potential is 1.53V, Nd doped Ti/Sb-SnO ₂The electrode oxygen evolution potential is 2.24V.

Oxygen evolution reaction mainly is because the OH of electrode surface absorption is unsettled with transferring to intracell O, except can reacting with organism, and also may be with O ₂Form discharge, oxygen evolution reaction promptly takes place.Oxygen evolution reaction is side reaction, can reduce the current efficiency of organic matter degradation, and the electrode materials with higher oxygen evolution potential can reduce the current loss that side reaction causes.

3. strengthen test electrode life

Damaged method is adopted in the test of electrode life.As shown in Table 1, rare earth Nd doped Ti/Sb-SnO ₂The electrode life of electrode is all long than blank electrode.This mainly is that structure by coating is determined.SEM photo by each electrode contrasts as can be known rear-earth-doped Ti/Sb-SnO ₂The coating of electrode is more even, fine and close, crystal formation is thin, the crack is few, matrix and be coated with interlayer and be difficult for form TiO in electrolytic process ₂Passive film, the bonding force between coating and matrix is stronger.Therefore, the doping of rare earth Nd makes Ti/Sb-SnO ₂The life-span of electrode prolongs.

The reinforcing life of table 1 electrode

4. catalytic activity relatively

By figure three as can be known, the catalytic activity of novel electrode obviously is better than blank electrode, and as can be known, Nd mixes and can improve the performance of electrode, improves catalytic efficiency.Nd has special 4f electronic structure, thereby very easily because of deformation takes place in polarization, thereby enter SnO with calking or metathetical mode ₂Intracell is because Nd ³⁺Ionic radius greater than Sn ⁴⁺Ionic radius (Sn ⁴⁺And Nd ³⁺Ionic radius be respectively 0.071nm and 0.0995nm), work as Nd ³⁺Enter SnO ₂Lattice dilatation can take place in intracell, causes charge unbalance, forms defectives such as room, hole in semiconductor material, thereby improves the electrode catalyst performance.In addition, the introducing of rare earth Nd may be at SnO ₂Introducing deep-level impurity in the internal layer semiconductor energy gap can be with, this similar forms semiconductor energy gap in add impurity such as Si, P in semiconductor material, these can provide a passage that energy level is lower with the transmission for electronics, help further improving the conductivity of electrode materials.

Description of drawings

Fig. 1 a is the SEM photo of the blank electrode of different amplification.

Fig. 1 b is the Nd doped Ti/Sb-SnO of different amplification ₂The SEM photo of electrode.

Fig. 2 is the electrokinetic potential scanning curve of electrode, wherein, and A, blank electrode; B, Nd doped Ti/Sb-SnO ₂Electrode.

Fig. 3 is different electrode percent of decolourization comparison diagrams.

Embodiment

Embodiment:

A kind of neodymium doped Ti/Sb-SnO ₂The preparation method of electrode, its preparation method is as follows:

1) electrode matrix pre-treatment

The titanium silk specification of electrode matrix titanium net is 1.5mm * 1.0mm, diamond mesh size 3mm * 8mm, and pretreatment process is:

(1) polishing

At first adopt mechanical polishing, remove electrode matrix oxide on surface and dirt, use 600 order sand papering corners again, make it slick and sly, rinse well with deionized water at last;

(2) alkali cleaning

It is 5% yellow soda ash (Na that entire electrode is immersed in mass concentration ₂CO ₃) in the washing lotion, keep each pole piece to be in separate stage, be heated to boiling, keep 1h, stop heating, cooling is rinsed well with deionized water;

(3) pickling

It is in 10% the oxalic acid washing lotion that entire electrode is immersed in mass concentration, and boiling state is handled 2-3h down, behind the deionized water rinsing surface impurity, puts into mass concentration and is 95% ethanol and preserve;

2) masking liquid preparation

With crystallization tin tetrachloride, butter of antimony and neodymium nitrate ratio in 100: 15: 1, be dissolved in the solvent, make masking liquid;

3) coating preparation

Adopt the immersion process for preparing electrode coating, concrete preparation method is:

(1) titanium electrode substrate is fully immersed in the masking liquid, keeps 1min;

(2) take out titanium electrode substrate, blow away unnecessary masking liquid with hair dryer;

(3) in 100-120 ℃ of baking oven, dry 10min, solvent is all volatilized;

(4) put into retort furnace, thermooxidizing 15min under 550 ℃ of environment;

(5) be cooled to room temperature, repeating step (1) is to (4), i.e. immersion, dry, thermooxidizing repeat 15 times, obtain neodymium-doped titanium base tindioxide-antimony electrode.

Claims (1)

1, a kind of preparation method of neodymium-doped titanium base tindioxide-antimony electrode is characterized in that, the preparation method is as follows:

1) electrode matrix pre-treatment

The titanium silk specification of electrode matrix titanium net is 1.5mm * 1.0mm, diamond mesh size 3mm * 8mm, and pretreatment process is:

(1) polishing

At first adopt mechanical polishing, remove electrode matrix oxide on surface and dirt, use 600 order sand papering corners again, make it slick and sly, rinse well with deionized water at last;

(2) alkali cleaning

It is 5% yellow soda ash (Na that entire electrode is immersed in mass concentration ₂CO ₃) in the washing lotion, keep each pole piece to be in separate stage, be heated to boiling, keep 1h, stop heating, cooling is rinsed well with deionized water;

(3) pickling

It is in 10% the oxalic acid washing lotion that entire electrode is immersed in mass concentration, and boiling state is handled 2-3h down, behind the deionized water rinsing surface impurity, puts into mass concentration and is 95% ethanol and preserve;

2) masking liquid preparation

With crystallization tin tetrachloride, butter of antimony and neodymium nitrate ratio in 100: 15: 1, be dissolved in the solvent, make masking liquid;

3) coating preparation

Adopt the immersion process for preparing electrode coating, concrete preparation method is:

(1) titanium electrode substrate is fully immersed in the masking liquid, keeps 1min;

(2) take out titanium electrode substrate, blow away unnecessary masking liquid with hair dryer;

(3) in 100-120 ℃ of baking oven, dry 10min, solvent is all volatilized;

(4) put into retort furnace, thermooxidizing 15min under 550 ℃ of environment;

(5) be cooled to room temperature, repeating step (1) is to (4), i.e. immersion, dry, thermooxidizing repeat 15 times, obtain neodymium-doped titanium base tindioxide-antimony electrode.

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