CN105435825A - Composite photocatalyst SiO2/CNI, preparation method therefor and application in field of hydrogen production by water photolysis - Google Patents

Abstract

The present invention provides a composite photocatalyst and a preparation method and an application thereof. The composite photocatalyst can catalytically decompose water under a visible light condition so as to prepare hydrogen, and provides a new approach to develop and utilize new energy sources. The composite photocatalyst is prepared by using a nitrogen-containing organic compound and an iodine-containing compound as raw materials, by calcining the raw materials to obtain iodine doped carbon nitride (CNI), and by compounding the obtained CNI with silicon dioxide. The preparation method is simple and feasible, and has excellent operability.

Description

A kind of composite photo-catalyst SiO 2/ CNI and preparation method thereof and the application in photolysis water hydrogen field

Technical field

The present invention relates to a kind of photochemical catalyst and its preparation method and application, particularly the photochemical catalyst SiO of photolysis water hydrogen ₂/ CNI and its preparation method and application.

Background technology

Graphite phase carbon nitride, namely, good stability, cost of material higher with its photocatalytic activity are cheap, especially not this outstanding advantages of containing metal, make it become a kind of novel catalysis material, but, the g-C of single-phase ₃n ₄catalyst makes its photocatalysis performance show usually because quantum efficiency is low not ideal enough.In addition, g-C ₃n ₄material photo-generate electron-hole recombination rate is higher, causes its catalytic efficiency lower, thus limits its application in photocatalysis.

In order to improve g-C ₃n ₄catalytic activity, recent years, people have studied a lot of method of modifying.One is to g-C with nonmetalloid ₃n ₄carry out modification, described nonmetalloid comprises S, N, C, B, F, P etc., it is generally acknowledged that these nonmetalloids instead of C, N, H element in 3-s-triazine structural units, thus forms g-C ₃n ₄lattice defect makes photo-generate electron-hole to being effectively separated, and effectively improves its photocatalysis performance.As mixed with BmimPF6 (ionic liquid) by dicyandiamide, after high-temperature calcination, obtain P doping g-C ₃n ₄through XPS analysis, catalyst, shows that P element instead of C in construction unit, although a small amount of P doping can not change g-C ₃n ₄structure, but it obviously changes g-C ₃n ₄electronic structure, photogenerated current is also apparently higher than undoped g-C ₃n ₄.For another example, to adulterate g-C adopting the mixture of heat resolve melamine and boron oxide to prepare B ₃n ₄, show that B instead of g-C through XPS spectrum analysis ₃n ₄h in structure, photocatalytic degradation of dye research shows that B doping improves the absorption of catalyst to light simultaneously, and therefore, rhodamine B photocatalytic degradation efficiency is also improved.For another example, by g-C ₃n ₄at H ₂prepare in 450 DEG C of calcinings in S atmosphere and there is unique electronic structure S element doping g-C ₃n ₄cNS catalyst, XPS analysis display S instead of g-C ₃n ₄n in structure, as λ > 300 and 420nm, S adulterates g-C ₃n ₄photocatalysis Decomposition aquatic products hydrogen catalysis efficiency is respectively than single-phase g-C ₃n ₄improve 7.2 and 8.0 times.For another example, NH is used ₄f obtains F element doping g-C as F source and DCDA ₃n ₄catalyst (CNF), F element mixes g-C ₃n ₄skeleton in, define C-F key, make wherein a part of sp2C be converted into sp3C, thus cause g-C ₃n ₄planar structure irregularity; In addition, along with F element doping increasing number, the absorption region of CNF in visible region also expands thereupon, and the band-gap energy of its correspondence drops to 2.63eV by 2.69eV.For another example, BH is used ₃nH ₃the g-C of B element doping is prepared as boron source ₃n ₄catalyst (CNB), mixing of B element, instead of g-C ₃n ₄c element in construction unit.For another example, adopt tetraphenylboron sodium as B source, while mixing B, again because the effect of benzene leaving group makes g-C ₃n ₄form laminate structure, the thickness of its layer is 2 ~ 5nm, reduces light induced electron and arrives the required energy consumed of catalyst surface, therefore improve photocatalysis efficiency.

At present, energy shortage problem is on the rise, and finding taps a new source of energy becomes the new problem of global scientific worker.In numerous new forms of energy, hydrogen is pollution-free with it, product is that water attracts tremendous attention, but extremely low at the content of occurring in nature hydrogen, therefore, be difficult to obtain enough hydrogen resources from occurring in nature be used, and in prior art, prepare the method mainly electrolysis of hydrogen, it consumes a large amount of energy when preparing hydrogen, and can produce pollution, therefore, needing that exploitation is a kind of badly can the method preparing hydrogen of easy pollution-free low energy consumption.

But above-mentioned preparation method not only complicated operation, cost of material is high, and obtained its photocatalysis efficiency of modified catalyst increases limitation, can not meet industrial requirements, and above-mentioned photochemical catalyst still can not be applied to the hydrogen manufacturing of photocatalytic degradation water.

Therefore, need exploitation one badly and there is high catalytic efficiency, and preparation method is simple, photochemical catalyst easy and simple to handle.

Summary of the invention

In order to solve the problem, present inventor has performed and study with keen determination, found that: using itrogenous organic substance and containing iodine compound as raw material, obtain the carbonitride (CNI) of I2 doping by the method for calcining, more obtained CNI obtained SiO with silica compound ₂/ CNI composite photo-catalyst, obtained composite photo-catalyst can in catalytic degradation water decomposition hydrogen manufacturing under visible light conditions, and its catalytic efficiency is high, thus completes the present invention.

The object of the present invention is to provide following aspect:

First aspect, the invention provides a kind of composite photo-catalyst SiO ₂/ CNI, is characterized in that, institute's compound is stated catalyst and comprised SiO ₂and CNI, wherein, SiO ₂be SiO with the weight ratio of CNI ₂weight: weight=1:(1 ~ 50 of CNI), be preferably 1:(3 ~ 40), be more preferably 1:(5 ~ 30), as 1:5,1:15,1:25,1:30.

Second aspect, the present invention also provides the application of composite photo-catalyst in photocatalytic water described in above-mentioned first aspect.

The third aspect, the present invention also provides one to prepare above-mentioned composite photo-catalyst SiO ₂the method of/CNI, is characterized in that, the method comprises the following steps:

(1) itrogenous organic substance is mixed with containing iodine compound, calcine, optionally cool, then purifying, obtain CNI sample;

(2) by CNI sample obtained for step 1 and SiO ₂mixing, calcines, obtained SiO ₂/ CNI product.

Accompanying drawing explanation

Fig. 1 illustrates the XRD spectra of the sample that embodiment 1 ~ 4 and comparative example 1 ~ 3 obtain;

Fig. 2 a illustrates that embodiment 2, comparative example 1 and comparative example 2 obtain the C1s energy level spectrogram of sample;

Fig. 2 b is CN, CNI and SiO ₂the high-resolution XPS spectrum figure of the N1s of/CNI;

Fig. 2 c is SiO ₂/ CNI and SiO ₂the high-resolution XPS spectrum figure of O1s;

Fig. 2 d is SiO ₂/ CNI and SiO ₂the high-resolution XPS spectrum figure of Si2p;

Fig. 2 e is SiO ₂the high-resolution XPS spectrum figure of the I3d of/CNI and CNI;

Fig. 3 illustrates the photoluminescence spectra of the sample that embodiment 2 and comparative example 1 ~ 3 obtain;

Fig. 4 illustrates the UV-Vis diffuse reflection spectroscopy of the sample that embodiment 2 and comparative example 1 ~ 3 obtain;

Fig. 5 illustrates that working sample degradation water produces the structural representation of hydrogen gas rate instrument;

Fig. 6 illustrates that the light degradation water of the sample that embodiment 1 ~ 4 and comparative example 2 obtain produces the speed of hydrogen.

Drawing reference numeral explanation

1-gas-chromatography

2-vacuum line

3-baroceptor

4-circulating pump

5-condenser pipe

6-magnetic stir bar

7-cooling water

8-optical filter

9-300W xenon lamp

10-argon gas.

Detailed description of the invention

Below by the present invention is described in detail, the features and advantages of the invention will illustrate along with these and become more clear, clear and definite.

Below in detail the present invention is described in detail.

According to a first aspect of the invention, the invention provides a kind of composite photo-catalyst SiO ₂/ CNI, is characterized in that, institute's compound is stated catalyst and comprised SiO ₂and CNI, wherein, SiO ₂be SiO with the weight ratio of CNI ₂weight: weight=1:(1 ~ 50 of CNI), be preferably 1:(3 ~ 40), be more preferably 1:(5 ~ 30), as 1:5,1:15,1:25,1:30.

Described composite photo-catalyst SiO ₂in its X-ray diffraction spectrum of/CNI, in 2 θ=21.06 °, 26.71 °, 36.70 °, 39.67 °, 40.57 °, 42.65 °, 46.03 °, the diffraction maximum near 50.30 ° and 54.95 ° corresponds respectively to (100), (011), (110), (102), (111), (200), (201), (112) and (022) crystal face.

Described composite photo-catalyst SiO ₂in its XPS of/CNI (X-ray electron spectrum) figure, in C1s energy level spectrum, C element has two Photoelectron peaks at energy position 284.1eV and 287.4eV place; In N1s energy level spectrum, N element has a Photoelectron peak at energy position 398.0eV place; In O1s energy level spectrum, O element has a Photoelectron peak at energy position 531.7eV place; In Si2p energy level spectrum, Si element has a Photoelectron peak at energy position 102.3eV place; In I3d energy level spectrum, I element is combining and can have two Photoelectron peaks for the energy position place of 621.5eV and 633.3eV.

Described composite photo-catalyst SiO ₂in its photoluminescence spectrum of/CNI, when excitation wavelength is 400nm, it is there is absworption peak near 450nm at wavelength.

Described composite photo-catalyst SiO ₂in its UV-Vis diffuse reflection spectroscopy of/CNI, it is there is absworption peak near 280nm and 380nm at wavelength.

According to a second aspect of the invention, the application of composite photo-catalyst in photocatalytic water described in above-mentioned first aspect is also provided.

At present, energy shortage problem has become ten big world problems, therefore, development of new clean energy resource is extremely urgent, and hydrogen is pollution-free with itself, its combustion product is the pollution-free first material as clean energy resource also, but, extremely low at occurring in nature hydrogen content, and the method preparing hydrogen at present needs to consume mass energy, therefore, the use promoting hydrogen is hindered always.

But the light degradation water catalyst existed in prior art mainly carries out photocatalytic degradation under ultraviolet light existent condition, and the speed of photocatalytic degradation is lower, is difficult to be applied to suitability for industrialized production.

In the present invention, composite photo-catalyst provided by the invention degradation water can prepare hydrogen under visible light illumination, hydrogen-producing speed is up to 88.6 μm of ol/h, do not need additionally to consume the energy in the process of catalytic degradation water hydrogen manufacturing, therefore, composite photo-catalyst provided by the invention can also be applied to photocatalytic water aspect.(specifically see experimental example 5)

The present inventor finds after deliberation, SiO ₂carrier has the features such as the large and loose structure of Dispersion on surface effect, specific area because of it, works as SiO ₂with graphite phase carbon nitride (g-C ₃n ₄) be compounded to form the semiconductors coupling type photochemical catalyst of binary after, its photocatalytic activity significantly improves, be not bound by any theory, the present inventor thinks, after described two kinds of different semiconductors carry out compound, photo-generated carrier can carry out transmitting and being separated between different energy level, thus extends the life-span of carrier, thus improves its catalytic reaction activity of light.

According to a third aspect of the invention we, one is provided to prepare above-mentioned composite photo-catalyst SiO ₂the method of/CNI, is characterized in that, the method comprises the following steps:

Step 1, mixes itrogenous organic substance with containing iodine compound, calcines, optionally cool, then purifying, obtain CNI sample.

In the present invention, described itrogenous organic substance refers to nitrogenous small organic molecule, refers to the nitrogenous small organic molecule that can decompose in a heated condition especially, and it is being prepared in graphite phase carbon nitride not only as nitrogen source but also as carbon source material.

The present inventor finds, uses the itrogenous organic substance of the small-molecular-weight that carbon-nitrogen ratio is 1:3 ~ 3:1 as raw material, preferably uses the small-molecular-weight itrogenous organic substance that carbon-nitrogen ratio is 1:2 as raw material, in 300 DEG C ~ 800 DEG C environment, can obtain cancellated g-C after roasting ₃n ₄, as cyanamide, dicyanodiamine, melamine, urea, guanidine hydrochloride etc., be preferably dicyanodiamine.

The present inventor finds through large quantity research, and dicyanodiamine can be decomposed in a heated condition, under roasting condition, easily generate g-C ₃n ₄, in addition, dicyanodiamine low price, easily obtains, and it is at generation g-C ₃n ₄other accessory substance rear is few, i.e. product g-C ₃n ₄middle impurity is few, is conducive to the purity improving end-product heterojunction photocatalyst, and the g-C obtained by dicyanodiamine ₃n ₄pattern is homogeneous, and layer structure is obvious, and therefore, the present invention preferably uses dicyanodiamine to prepare g-C ₃n ₄.

In the present invention, described containing iodine compound be selected from be easy in a heated condition to decompose containing iodine compound, preferably from ammonium iodide and/or iodoform etc., be more preferably ammonium iodide.

The present inventor finds, the decomposition temperature of ammonium iodide is low, and take conveniently, the product obtained after decomposition is easy to process, and environmental pollution is little, therefore, is preferably ammonium iodide in the present invention containing iodine compound.

In the present invention, described itrogenous organic substance is (0.5 ~ 5) with the weight ratio containing iodine compound: 1, is preferably (1 ~ 4): 1, is more preferably (1.5 ~ 3): 1, as 2:1.When itrogenous organic substance is greater than 5:1 with the weight ratio containing iodine compound, itrogenous organic substance addition is excessive, cause I content in the CNI product obtained very few, thus atomic iodine is at g-C ₃n ₄in occupy-place not enough, carry out the catalytic activity reducing final obtained photochemical catalyst; When itrogenous organic substance is less than 0.5:1 with the weight ratio containing iodine compound, the addition of itrogenous organic substance is too small, namely, addition containing iodine compound is excessive, cause atomic iodine seriously to hamper the transmission of photo-generated carrier between different energy level and be separated, thus also reduce the photocatalysis efficiency of end product.

This has and is not particularly limited to itrogenous organic substance with containing iodine compound hybrid mode, can use the mode of any one pressed powder mixing in prior art, as direct mixing, and sonic oscillation, mechanical agitation and liquid phase mixing etc.

One of the present invention preferred embodiment in, itrogenous organic substance is mixed with the mode mixed by liquid phase containing iodine compound, concrete grammar is: by nitrogen-containing compound be scattered in solvent containing iodine compound, described two kinds of raw materials are made fully to dissolve in a heated condition, solvent after dissolving in removing system, drying and crushing, the itrogenous organic substance that must mix and the mixture containing iodine compound, wherein

Described solvent be preferably selected from water, deionized water and/or, described heating condition is preferably 60 DEG C ~ 80 DEG C, is more preferably 70 DEG C ~ 80 DEG C, as 80 DEG C.

Optionally, pulverized by the mixture obtained, the present invention is not particularly limited to the particle diameter after pulverizing.

The present inventor finds, after being pulverized by the mixture obtained, then calcine, significantly can shorten calcination time, and mixture is calcined more full and uniform, the pattern obtaining intermediate product after calcining is more homogeneous.

In calcination process of the present invention, heating rate is selected to be 10 ~ 30 DEG C of min ^-1, be preferably 15 ~ 25 DEG C of min ^-1, as 20 DEG C of min ^-1.The present inventor finds, when heating rate is greater than 30 DEG C of min ^-1time, obtained product morphology is uneven; When heating rate is lower than 10 DEG C of min ^-1time, the reaction time is long, and has accessory substance to produce.

In step 1 of the present invention, described calcining is carried out under 300 ~ 800 DEG C of conditions, is preferably 400 DEG C ~ 700 DEG C, is more preferably 500 DEG C ~ 600 DEG C, as 550 DEG C.

In step 1 of the present invention, select calcination time to be 1 ~ 10 hour, be preferably 2 ~ 8 hours, be more preferably 3 ~ 6 hours, as 4 hours.Be less than 1 constantly little upon calcination, calcination time is too short, reacts insufficient, and raw material is remaining completely still unreacted in reaction system; After being greater than 10 hours upon calcination, raw material fully reacts, the no longer showed increased of the product in system, continues to extend calcination time and can only cause the waste of the energy and the increase of time cost.

In a preferred embodiment of the invention, select in confined conditions to the roasting that raw material carries out, avoid raw material too to contact with oxygen, thus the significant loss reducing raw material complete oxidation and bring.

Optionally, obtained material is carried out cooling down, the method for the present invention to cooling down is not particularly limited to, and any one can be used in prior art by the method for solid cooled, as natural cooling, artificial cooling method etc., to be preferably natural cooling.

Optionally, pulverize calcining the material obtained, the present inventor finds, pulverizing calcining the material obtained, being conducive to fully carrying out of subsequent reactions, the end-product that step 3 also can be made obtained is more even, and performance is more stable.

In the present invention, to pulverize after particle diameter be not particularly limited to, with SiO ₂particle diameter be close to preferably.

In the present invention, described purifying comprises the steps such as once washing, pickling, alkali cleaning and secondary washing.

The CNI sample that step 1 of the present invention obtains both was not dissolved in water, was also not dissolved in acid, was also not dissolved in alkali, the impurity that wherein may contain then can be dissolved at least one in water, acid or alkali, and therefore, the present invention selects thick for obtained CNI product first to wash with water, remove wherein water-solubility impurity, remove wherein alkaline impurities with pickling again, then remove wherein acid impurities with alkali cleaning, finally wash with water again, remove excessive alkali, obtain pure CNI sample, wherein

Described washing water used is deionized water, distilled water, distilled water etc.;

Described pickling acid used is selected from hydrochloric acid, sulfuric acid and nitric acid etc., is preferably selected from the hydrochloric acid that concentration is 1mol/L;

Described alkali cleaning alkali used is selected from sodium hydroxide solution, potassium hydroxide solution, limewash and ammoniacal liquor etc., and being preferably concentration is the sodium hydroxide solution of 1mol/L.

Optionally, the CNI sample that purifying obtains carries out drying process, and the mode of the present invention to drying is not particularly limited to, and can use the method for any one solid drying in prior art.

One of the present invention preferred embodiment in, baking temperature is 50 DEG C ~ 100 DEG C, be preferably 60 DEG C ~ 90 DEG C, as 80 DEG C, drying time is 1 ~ 10 hour, be preferably 3 ~ 8 hours, as 5 hours.

Step 2, the CNI sample obtained by step 1 and SiO ₂mixing, calcines, obtained SiO ₂/ CNI product.

In the present invention, SiO is selected ₂particle diameter be 40 ~ 110nm, be preferably 50 ~ 80nm, as 60 ~ 70nm.

In the present invention, to CNI sample and SiO ₂the mode of mixing is not particularly limited to, and can use the mode that in prior art, any one powder mixes with powder, as mechanical agitation, grinding or liquid phase mixing etc., the present invention is preferably grinding, the time of grinding is preferably 10 ~ 40 minutes, is more preferably 15 ~ 30 minutes, as 20 minutes.

In the present invention, SiO ₂be 1:(1 ~ 50 with the weight ratio of CNI sample), be preferably 1:(3 ~ 40), as 1:5,1:15,1:25 and 1:30.

The present inventor finds, works as SiO ₂when being 1:15 with the weight ratio of CNI sample, the photocatalysis efficiency of obtained composite photo-catalyst is the highest.

As CNI sample and SiO ₂after mixing, mixture is calcined.

In step 2 of the present invention, described calcining is carried out under 300 ~ 800 DEG C of conditions in temperature, is preferably 400 DEG C ~ 700 DEG C, is more preferably 500 DEG C ~ 600 DEG C, as 550 DEG C.

In step 2 of the present invention, select calcination time to be 1 ~ 10 hour, be preferably 2 ~ 8 hours, be more preferably 3 ~ 6 hours, as 4 hours.Be less than 1 constantly little upon calcination, calcination time is too short, reacts insufficient, and raw material is remaining completely still unreacted in reaction system; After being greater than 10 hours upon calcination, raw material fully reacts, the no longer showed increased of the product in system, continues to extend calcination time and can only cause the waste of the energy and the increase of time cost.

Optionally exist, in step 2, pulverized by the product after calcining, the present invention is not particularly limited to the mode pulverized, and can use the mode that in prior art, any one solid is pulverized, as grinding etc.

The composite photo-catalyst SiO that the present invention obtains ₂in/CNI, SiO ₂be SiO with the weight ratio of CNI ₂weight: weight=1:(1 ~ 50 of CNI), be preferably 1:(3 ~ 40), be more preferably 1:(5 ~ 30), as 1:5,1:15,1:25,1:30.

Described composite photo-catalyst SiO ₂in its X-ray diffraction spectrum of/CNI, in 2 θ=21.06 °, 26.71 °, 36.70 °, 39.67 °, 40.57 °, 42.65 °, 46.03 °, the diffraction maximum near 50.30 ° and 54.95 ° corresponds respectively to (100), (011), (110), (102), (111), (200), (201), (112) and (022) crystal face.

Described composite photo-catalyst SiO ₂in its XPS of/CNI (X-ray electron spectrum) figure, in C1s energy level spectrum, C element has two Photoelectron peaks at energy position 284.1eV and 287.4eV place; In N1s energy level spectrum, N element has a Photoelectron peak at energy position 398.0eV place; In O1s energy level spectrum, O element has a Photoelectron peak at energy position 531.7eV place; In Si2p energy level spectrum, Si element has a Photoelectron peak at energy position 102.3eV place; In I3d energy level spectrum, I element is combining and can have two Photoelectron peaks for the energy position place of 621.5eV and 633.3eV.

Described composite photo-catalyst SiO ₂in its photoluminescence spectrum of/CNI, when excitation wavelength is 400nm, it is there is absworption peak near 450nm at wavelength.

Described composite photo-catalyst SiO ₂in its UV-Vis diffuse reflection spectroscopy of/CNI, it is there is absworption peak near 280nm and 380nm at wavelength.

According to composite photo-catalyst of photolysis water hydrogen provided by the invention and its preparation method and application, there is following beneficial effect:

(1) composite photo-catalyst provided by the invention can under visible ray existent condition degradation water, obtained hydrogen, for development and utilization new forms of energy have sought a new approach;

(2) the described composite photo-catalyst catalytic efficiency of degrading to water is high, the non-environmental-pollution of composite catalyst own, and it does not also produce environmental pollution in the process of catalytic degradation water, is a kind of catalyst of environmental protection;

(3) method of described obtained composite photo-catalyst is easy, is easy to operate and control reaction condition, obtained composite photo-catalyst stable performance.

Embodiment

embodiment 1

(1) accurately take 2.0g dicyanodiamine and 1.0g ammonium iodide is placed in small beaker (ammonium iodide answers lucifuge to take), add 10ml deionized water, small beaker is placed in 80 DEG C of water-baths in 80 DEG C of water-bath 6h evaporates to dryness; The sample obtained is put into agate mortar porphyrize, and be then put in crucible and be placed in 550 DEG C of calcining 4h in chamber type electric resistance furnace, then take out, the sample obtained is cooled to room temperature, porphyrize loads sample sack, obtained CNI catalyst former state;

Gained CNI former state is transferred in the small beaker filling 80mL distilled water, then through washing, pickling (HCl, 1mol/L), alkali cleaning (NaOH, 1mol/L), washes again, all unreacted harmful surface masses of suction filtration removing; By handle well sample put into 80 DEG C of baking ovens, dry 5h, to be dried complete after, by sample porphyrize, obtain pure CNI sample.

(2) SiO of the obtained pure CNI sample of 3.0000g step 1 and 0.6000g is accurately taken respectively ₂mixing, after mixing, is placed in agate mortar grinding 20min, is then placed in chamber type electric resistance furnace in 550 DEG C of calcinings 4h, obtained composite catalyst SiO ₂/ CNI (1:5).

embodiment 2 ~ 4

Embodiment 2 ~ 4 method therefor is similar to embodiment 1, and difference is only SiO in step (2) ₂weight be respectively 0.2000g, 0.1200g and 0.1000g, obtained composite catalyst is respectively SiO ₂/ CNI (1:15), SiO ₂/ CNI (1:25), SiO ₂/ CNI (1:30).

Comparative example

comparative example 1

10.0g dicyanodiamine is placed in small beaker, adds 10ml deionized water, small beaker is placed in 80 DEG C of water-baths in 80 DEG C of water-bath 6h evaporates to dryness; The sample obtained is put into agate mortar porphyrize, and be then put in crucible and be placed in 550 DEG C of calcining 4h in chamber type electric resistance furnace, then take out, the sample obtained is cooled to room temperature, porphyrize loads sample sack, obtained CN catalyst former state;

Gained CN former state is transferred in the small beaker filling 80mL distilled water, then through washing, pickling (HCl, 1mol/L), alkali cleaning (NaOH, 1mol/L), washes again, all unreacted harmful surface masses of suction filtration removing; By handle well sample put into 80 DEG C of baking ovens, dry 5h, to be dried complete after, by sample porphyrize, obtain pure CN sample.

comparative example 2

This comparative example specimen in use is sheerly CNI sample obtained in embodiment 1 step (1).

comparative example 3

This comparative example specimen in use is SiO used in embodiment 1 step (2) ₂sample.

Experimental example

the XRD test of experimental example 1 sample

This experimental example specimen in use is the sample that embodiment 1 ~ 4 and comparative example 1 ~ 3 obtain.

Method of testing: adopt BrukerD8Advance type X-ray diffractometer (XRD), copper target (CuK α (λ=0.154nm)) ray, Ni optical filter, operating voltage 40kV, electric current 40mA, sweep limits 2 θ=10 ° ~ 60 °, analyze the crystal phase structure of sample, result as shown in Figure 1, wherein

Curve a represents the XRD spectrum of comparative example 3 sample;

Curve b represents that comparative example 1 obtains the XRD spectrum of sample;

Curve c represents that comparative example 2 obtains the XRD spectrum of sample;

Curve d represents that embodiment 1 obtains the XRD spectrum of sample;

Curve e represents that embodiment 2 obtains the XRD spectrum of sample;

Curve f represents that embodiment 3 obtains the XRD spectrum of sample;

Curve g represents that embodiment 4 obtains the XRD spectrum of sample;

As shown in Figure 1:

Curve a represents SiO ₂diffraction maximum, in 2 θ=21.06 °, 26.71 °, 36.70 °, 39.67 °, 40.57 °, 42.65 °, 46.03 °, the diffraction maximum of 50.30 ° and 54.95 ° corresponds respectively to (100), (011), (110), (102), (111), (200), (201), (112) and (022) crystal face, the diffraction maximum occurred all can and SiO ₂be consistent.

Curve b represents CN diffraction maximum, and 2 θ=13.51 ° and 27.63 ° correspond respectively to (100) and (002) crystal face.

Curve c represents CNI diffraction maximum, and 2 θ=27.68 ° correspond to (002) crystal face.

Equally, prepared in experiment SiO ₂/ CNI composite photocatalyst sample in 2 θ=21.06 °, 26.71 °, 36.70 °, 39.67 °, 40.57 °, 42.65 °, 46.03 °, the diffraction maximum near 50.30 ° and 54.95 ° corresponds respectively to (100), (011), (110), (102), (111), (200), (201), (112) and (022) crystal face, this also illustrates SiO in composite catalyst ₂obtain sufficient compound with CNI, do not produce novel substance.

From curve d, curve e, curve f and curve g, diffraction maximum corresponding during 2 θ=26.71 ° is the strongest, and, at composite S iO ₂in/CNI catalyst sample, along with SiO ₂increase with CNI mass ratio, SiO ₂diffraction peak intensity strengthen gradually, work as SiO ₂when being 1:15 with CNI mass ratio, diffraction peak intensity is the strongest, subsequently, along with SiO ₂increase with CNI mass ratio, SiO ₂diffraction peak intensity weaken gradually.Namely, during 2 θ=26.71 °, diffraction peak intensity order is g<f<e>d, from diffraction peak intensity and catalyst activity corresponding relation, works as SiO ₂when being 1:15 with CNI mass ratio, the catalytic activity of catalyst is the highest.

the XPS test of experimental example 2 sample

This experimental example specimen in use is the sample that embodiment 2 and comparative example 1 ~ 3 obtain.

Test condition: adopt Brooker 2000XPS instrument (x-ray photoelectron spectroscopy) each catalyst sample is characterized, result as shown in Fig. 2 a ~ Fig. 2 e, wherein,

Fig. 2 a is that (curve a1 illustrates CN sample spectrogram to C1s energy level spectrogram, and curve b1 illustrates CNI sample spectrogram, and curve c1 illustrates SiO ₂/ CNI (1:15) sample spectrogram);

Fig. 2 b is CN, CNI and SiO ₂(curve a2 illustrates CN sample spectrogram to the high-resolution XPS spectrum figure of the N1s of/CNI, and curve b2 illustrates CNI sample spectrogram, and curve c2 illustrates SiO ₂/ CNI (1:15) sample spectrogram);

Fig. 2 c is SiO ₂/ CNI and SiO ₂the high-resolution XPS spectrum figure of O1s (curve a3 illustrates SiO ₂/ CNI sample spectrogram, curve b3 illustrates SiO ₂sample spectrogram);

Fig. 2 d is SiO ₂/ CNI and SiO ₂the high-resolution XPS spectrum figure of Si2p (curve a4 illustrates SiO ₂/ CNI sample spectrogram, curve b4 illustrates SiO ₂sample spectrogram);

Fig. 2 e is SiO ₂(curve a5 illustrates SiO to the high-resolution XPS spectrum figure of the I3d of/CNI and CNI ₂/ CNI sample spectrogram, curve b5 illustrates CNI sample spectrogram).

From Fig. 2 a, C element has two Photoelectron peaks, in conjunction with being respectively 284.1eV and 287.4eV, wherein the peak at 284.1eV place should belong to the C atom (N-C=N) of sp2 hydridization in circulus, the peak at 287.4eV place belongs to the C atom in the C-N key in graphite structure, further, the peak position that goes out of C1s track offsets.

From Fig. 2 b, for CN, N element has a Photoelectron peak, in conjunction with being 398.0eV, be attributed to the atom N (C-N=C) of sp2 hydridization, when I is introduced in CN main body, in conjunction with slightly combining can move in direction to height, CNI and SiO for the N1s energy of 398.0eV ₂the N1s of/CNI combines and can move to 398.1eV.

From Fig. 2 c, O element mainly containing a Photoelectron peak, in conjunction with being 531.7eV, being attributed to the O atom (Si-O) of sp hydridization, working as SiO ₂after CNI compound, because CNI is to SiO ₂generation effect, makes to combine and slightly can combine can move in direction to height for the O1s energy of 531.7eV, move to 531.8eV.

From Fig. 2 d, Si element mainly containing a Photoelectron peak, in conjunction with being 102.3eV, be attributed to the Si atom (Si-O) of sp3 hydridization.Work as SiO ₂after CNI compound, because CNI is to SiO ₂generation effect, makes to combine and slightly can combine can move in direction to height for the Si2p energy of 102.3eV, move to 102.88eV.

From the Photoelectron peak of Fig. 2 e, I element mainly containing two different-energy positions, in conjunction with being respectively 621.5eV and 633.3eV.

the photoluminescence spectra of experimental example 3 sample

Photoluminescence spectra (PL) is the blemish that can disclose semiconductor nano material and being separated and the information such as compound of the architectural characteristic such as Surface Oxygen room and photo-generated carrier (electron-hole pair).

This experimental example specimen in use is the sample that embodiment 2 and comparative example 1 ~ 3 obtain.

Method of testing: take a morsel CN, CNI pure sample, SiO ₂/ CNI (1:15) catalyst sample (pulverulence), puts into the optical filter of 400nm, makes excitation wavelength be 400nm, press fine and close with slide by sample as far as possible, utilize XRF to test the photoluminescence performance of sample, result as shown in Figure 3, wherein

Curve a represents that embodiment 2 obtains sample (SiO ₂/ CNI (1:15)) photoluminescence spectra curve;

Curve b represents that comparative example 2 obtains the photoluminescence spectra curve of sample (CNI);

Curve c represents that comparative example 1 obtains the photoluminescence spectra curve of sample (CN).

As shown in Figure 3, within the scope of wavelength 400 ~ 600nm, CN photochemical catalyst sample (pulverulence) shows not only strong but also wide luminous signal.

CNI and SiO ₂/ CNI (1:15) photochemical catalyst sample (pulverulence), shows similar signal peak equally within the scope of wavelength 400-600nm, but CNI and SiO2/CNI (1:15) peak intensity is weak compared with CN many.

For SiO ₂/ CNI (1:15) catalyst sample (pulverulence) is that within the scope of 400-600nm, signal peak is more weak at wavelength.

It is generally acknowledged, fluorescence signal is stronger, and the recombination probability of electron-hole pair is higher, and photocatalytic activity is just corresponding lower, and therefore, from Fig. 3, the activity order of catalyst is: SiO ₂/ CNI (1:15) catalyst activity is the strongest, and CNI catalyst activity takes second place, and the activity of CN catalyst is minimum, i.e. a>b>c.

the UV-Vis diffuse reflection spectroscopy of experimental example 4 sample

This experimental example specimen in use is the sample that embodiment 2 and comparative example 1 ~ 3 obtain.

Method of testing: the pure CN that takes a morsel, pure CNI, SiO ₂/ CNI (1:15) catalyst sample (pulverulence), utilizes UV-Vis diffuse reflection spectroscopy instrument to characterize each catalyst sample, test wavelength 200 ~ 800nm, result as shown in Figure 4, wherein,

Curve a represents that comparative example 1 obtains the UV-Vis diffuse reflection spectroscopy of sample (CN);

Curve b represents that comparative example 2 obtains the UV-Vis diffuse reflection spectroscopy of sample (CNI);

Curve c represents that embodiment 2 obtains sample (SiO ₂/ CNI (1:15)) UV-Vis diffuse reflection spectroscopy.

As shown in Figure 4, compared with CN, CNI, SiO ₂the light absorpting ability (200 ~ 600nm) of/CNI (1:15) sample is stronger, and it to the strong and weak order of light absorpting ability is: c>b>a, i.e. SiO ₂/ CNI (1:15) >CNI>CN; And can be found out by Fig. 4, absorb band edge and obviously move to long wave direction, namely catalyst activity order is: SiO ₂/ CNI (1:15) >CNI>CN.

experimental example 5 sample light degradation water produces hydrogen active testing

This experimental example specimen in use is the sample that embodiment 1 ~ 4 and comparative example 2 obtain.

Tester: the structural representation of this experimental example instrument as shown in Figure 5.

Method of testing: take the above-mentioned catalyst sample of 0.0500g respectively and join in 100ml triethanolamine (10vol.%) aqueous solution, ultrasonic mix after pour in reaction vessel, then add 3wt.%H in mixed liquor ₂ptCl ₆solution, and the suspended state being maintained solution by magnetic agitation, make the temperature of reaction system maintain 10 ± 1 DEG C by recirculated cooling water, again system is vacuumized repeatedly, after removing the air in reactor and solution completely, open light source and carry out light-catalyzed reaction, the wavelength of incident light is controlled by cut-off type optical filter, control as λ >420nm, every 1h sampling, by gas-chromatography on-line analysis product, result as shown in Figure 6, wherein

Curve a represents that sample CNI light degradation water produces the speed of hydrogen;

Curve b represents sample SiO ₂/ CNI (1:5) light degradation water produces the speed of hydrogen;

Curve c represents sample SiO ₂/ CNI (1:15) light degradation water produces the speed of hydrogen;

Curve d represents sample SiO ₂/ CNI (1:25) light degradation water produces the speed of hydrogen;

Curve e represents sample SiO ₂/ CNI (1:30) light degradation water produces the speed of hydrogen.

As shown in Figure 6, compared with producing hydrogen activity with pure sample CNI, due to SiO ₂load, make SiO ₂the hydrogen-producing speed of/CNI series of samples is all significantly improved.

In addition, the present inventor also finds SiO ₂the photocatalysis performance of/CNI and SiO ₂closely related with CNI mass ratio, work as SiO ₂when being 1:15 with CNI mass ratio, SiO ₂/ CNI photodissociation aquatic products hydrogen activity is the highest, Fig. 6 shows photodissociation aquatic products hydrogen activity order: a<b<c>dGreatT.Gr eaT.GTe, this has fully demonstrated the superiority of the photochemical catalyst after compound, and demonstrates the conclusion of spectral characterization in previous experiments example further.

More than in conjunction with detailed description of the invention and exemplary example to invention has been detailed description, but these explanations can not be interpreted as limitation of the present invention.It will be appreciated by those skilled in the art that when not departing from spirit and scope of the invention, can carry out multiple equivalencing, modification or improvement to technical solution of the present invention and embodiment thereof, these all fall within the scope of the present invention.Protection scope of the present invention is as the criterion with claims.

Claims (10)

1. a composite photo-catalyst SiO ₂/ CNI, is characterized in that, institute's compound is stated catalyst and comprised SiO ₂and CNI, wherein, SiO ₂be SiO with the weight ratio of CNI ₂weight: weight=1:(1 ~ 50 of CNI), be preferably 1:(3 ~ 40), be more preferably 1:(5 ~ 30), as 1:5,1:15,1:25,1:30.

2. composite photo-catalyst SiO according to claim 1 ₂/ CNI, is characterized in that,

According to its X-ray diffraction spectrum, in 2 θ=21.06 °, 26.71 °, 36.70 °, 39.67 °, 40.57 °, 42.65 °, 46.03 °, the diffraction maximum near 50.30 ° and 54.95 ° corresponds respectively to (100), (011), (110), (102), (111), (200), (201), (112) and (022) crystal face; And/or

According to its XPS spectrum (X-ray electron spectrum), in C1s energy level spectrum, C element has two Photoelectron peaks at energy position 284.1eV and 287.4eV place; In N1s energy level spectrum, N element has a Photoelectron peak at energy position 398.0eV place; In O1s energy level spectrum, O element has a Photoelectron peak at energy position 531.7eV place; In Si2p energy level spectrum, Si element has a Photoelectron peak at energy position 102.3eV place; In I3d energy level spectrum, I element is combining and can have two Photoelectron peaks for the energy position place of 621.5eV and 633.3eV; And/or

According to its photoluminescence spectrum, when excitation wavelength is 400nm, it is there is absworption peak near 450nm at wavelength; And/or

According to its UV-Vis diffuse reflection spectroscopy, it is there is absworption peak near 280nm and 380nm at wavelength.

3. the application of composite photo-catalyst according to claim 1 and 2 in photocatalytic water.

4. prepare the composite photo-catalyst SiO described in claim 1 or 2 for one kind ₂the method of/CNI, is characterized in that, the method comprises the following steps:

(1) itrogenous organic substance is mixed with containing iodine compound, calcine, optionally cool, then purifying, obtain CNI sample;

(2) by CNI sample obtained for step 1 and SiO ₂mixing, calcines, obtained SiO ₂/ CNI product.

5. method according to claim 4, is characterized in that, in step 1,

Described itrogenous organic substance refers to nitrogenous small organic molecule, refer to the nitrogenous small organic molecule that can decompose in a heated condition especially, be preferably, carbon-nitrogen ratio is the itrogenous organic substance of the small-molecular-weight of 1:3 ~ 3:1, be more preferably the small-molecular-weight itrogenous organic substance that carbon-nitrogen ratio is 1:2, as cyanamide, dicyanodiamine, melamine, urea, guanidine hydrochloride etc., be preferably dicyanodiamine; And/or

Described containing iodine compound be selected from be easy in a heated condition to decompose containing iodine compound, preferably from ammonium iodide and/or iodoform etc., be more preferably ammonium iodide.

6. the method according to claim 4 or 5, is characterized in that, in step 1, described itrogenous organic substance is (0.5 ~ 5) with the weight ratio containing iodine compound: 1, be preferably (1 ~ 4): 1, be more preferably (1.5 ~ 3): 1, as 2:1.

7. according to the method one of claim 4 ~ 6 Suo Shu, it is characterized in that, in step 1, described calcining is carried out under 300 ~ 800 DEG C of conditions, is preferably 400 DEG C ~ 700 DEG C, is more preferably 500 DEG C ~ 600 DEG C, as 550 DEG C; And/or

Calcination time is 1 ~ 10 hour, is preferably 2 ~ 8 hours, is more preferably 3 ~ 6 hours, as 4 hours.

8. according to the method one of claim 4 ~ 7 Suo Shu, it is characterized in that, in step 1, described purifying comprises the steps such as once washing, pickling, alkali cleaning and secondary washing.

9., according to the method one of claim 4 ~ 8 Suo Shu, it is characterized in that, in step 2,

SiO ₂be 1:(1 ~ 50 with the weight ratio of CNI sample), be preferably 1:(3 ~ 40), as 1:5,1:15,1:25 and 1:30; And/or

Described calcining is carried out under 300 ~ 800 DEG C of conditions in temperature, is preferably 400 DEG C ~ 700 DEG C, is more preferably 500 DEG C ~ 600 DEG C, as 550 DEG C; And/or

Calcination time is 1 ~ 10 hour, is preferably 2 ~ 8 hours, is more preferably 3 ~ 6 hours, as 4 hours.

10. according to the method one of claim 4 ~ 9 Suo Shu, it is characterized in that, SiO in obtained product ₂be SiO with the weight ratio of CNI ₂weight: weight=1:(1 ~ 50 of CNI), be preferably 1:(3 ~ 40), be more preferably 1:(5 ~ 30), as 1:5,1:15,1:25,1:30; And/or

According to its X-ray diffraction spectrum, in 2 θ=21.06 °, 26.71 °, 36.70 °, 39.67 °, 40.57 °, 42.65 °, 46.03 °, the diffraction maximum near 50.30 ° and 54.95 ° corresponds respectively to (100), (011), (110), (102), (111), (200), (201), (112) and (022) crystal face; And/or

According to its XPS spectrum (X-ray electron spectrum), in C1s energy level spectrum, C element has two Photoelectron peaks at energy position 284.1eV and 287.4eV place; In N1s energy level spectrum, N element has a Photoelectron peak at energy position 398.0eV place; In O1s energy level spectrum, O element has a Photoelectron peak at energy position 531.7eV place; In Si2p energy level spectrum, Si element has a Photoelectron peak at energy position 102.3eV place; In I3d energy level spectrum, I element is combining and can have two Photoelectron peaks for the energy position place of 621.5eV and 633.3eV; And/or

According to its photoluminescence spectrum, when excitation wavelength is 400nm, it is there is absworption peak near 450nm at wavelength; And/or

According to its UV-Vis diffuse reflection spectroscopy, it is there is absworption peak near 280nm and 380nm at wavelength.