CN102698775A - BiOI-graphene visible light catalyst and preparation method thereof - Google Patents

Abstract

The invention relates to a BiOI-graphene visible light catalyst and a preparation method thereof, belonging to the technical field of inorganic material synthesis and photocatalysis. BiOI and graphene are in the shape of a slice, and the graphene is 1.0%-3.0% by weight. The preparation method of the BiOI-graphene visible light catalyst comprises the following steps of: firstly ultrasonically dispersing graphite oxides into ethanol; then stirring, and adding a certain amount of sodium iodide or potassium iodide water solutions and bismuth nitrate glacial acetic acid solutions at the same time; transferring suspending liquid into a high-pressure reaction kettle with a polytetrafluoroethylene liner, and carrying out crystallization reaction at 120-150 DEG C for 6-12 hours; filtering, washing and drying obtain solid products so as to finally obtain the BiOI-graphene compound light catalyst. The preparation method has environment friendliness and simple process; and the prepared BiOI-graphene visible light catalyst has very high visible light catalytic activity and potential application value in a control technology decomposing organic pollutants by utilizing solar photocatalysis.

Description

A kind of BiOI-Graphene visible light catalyst and preparation method thereof

Technical field

The present invention relates to a kind of BiOI-Graphene visible light catalyst and preparation method thereof, belong to the synthetic and photocatalysis technology field of inorganic material.

Background technology

In recent years, energy shortage and environmental pollution become the significant problem that threatens human survival and health day by day.Photocatalysis technology be a kind of be that catalyst utilizes the green environment of solar energy degraded organic environment pollutant to administer new technology with the semiconductor.TiO ₂Stable chemical performance, nontoxic, inexpensive is present the most frequently used semiconductor light-catalyst, but TiO ₂Photochemical catalyst can be with broad (Eg=3.2 eV), only can not be utilized the visible light in the sunshine by the ultraviolet excitation in the sunshine (accounting for 3.8 % of solar energy), makes that its solar energy utilization ratio is low, has seriously hindered its large-scale commercial applications popularization.Therefore, the visible light-responded photochemical catalyst of development is to improve solar energy utilization ratio and the final key that realizes the photocatalysis technology commercial application.

Bismuth oxyiodide (BiOI) is a kind of novel visible light catalyst, and its energy gap is 1.77 eV, and most of visible light capable of using excites, and degradation effect is obvious, in commercial Application, has a high potential.But the absorption wavestrip of single kind BiOI photochemical catalyst is narrower, and its photocatalysis performance still awaits further raising.At present, less to the study on the modification of BiOI, as: Wang etc. had once prepared the BiOBr-BiOI compound, the result show the photocatalysis performance of compound to be higher than single BiOI (Catal. Commun. 2008,9,8-12).Zhang etc. are with TiO ₂Compound with BiOI, the BiOI/TiO of preparation ₂The hetero-junctions catalyst in 2 h to the degradation rate of methyl orange up to 95%, and the degradation rate of single BiOI be merely 2% (J. Phys. Chem. C. 2009,113,7371-7378).In addition, through BiOI and ZnO (J. Phys. Chem. C, 2011,115,20555-20564), Bi ₂O ₃(Catal. Commun., 2011,12, the surface modification of compound or noble metal 660-664) (Appl. Catal. B:Environ., 2012,111-112,271-279) all can greatly improve the photocatalysis performance of BiOI.

Graphene is the allotrope of found in recent years a kind of new carbon, and it is by sp ²The cellular two dimensional crystal that the monolayer carbon atom of hydridization is formed has excellent mechanics, calorifics, optics and electric property and the specific area of super large.Graphene and semiconductor light-catalyst recombination energy are effectively reduced the electronics-hole-recombination rate of photochemical catalyst, can increase the adsorption capacity of photochemical catalyst simultaneously pollutant.Therefore, Graphene and BiOI are carried out compound photocatalysis performance to further raising BiOI and have positive effect.But up to the present, also do not see the report that BiOI-Graphene composite visible light catalyst is arranged.

Summary of the invention

The object of the invention aims to provide a kind of BiOI-Graphene composite visible light catalyst and preparation method thereof.

A kind of BiOI-Graphene of the present invention composite visible light catalyst is characterized in that, is made up of BiOI and Graphene, and it is laminar that BiOI and Graphene all are, and the mass percent of Graphene is 1.0 %-3.0 %.

A kind of method for preparing BiOI-Graphene composite photo-catalyst of the present invention is characterized in that, has following preparation process and step:

(a) 0.007-0.022 g graphite oxide is dispersed in the 15-25 ml ethanol, abundant ultrasonic 1-2 h obtains the suspension of graphene oxide;

(b) under the room temperature, the bismuth nitrate of 0.002 mol is dissolved in the glacial acetic acid of 3-10 ml, under agitation adds sodium iodide or KI and the 10-50 ml deionized water of 0.002 mol again;

(c) step (a) gained suspension slowly is added drop-wise in step (b) the gained solution;

(d) with behind step (c) gained solution stirring 2 h, transfer in the autoclave of teflon gasket, at 120-150 ℃ of following crystallization 6-12 h;

(e) solid product that obtains is through filtering, and washing gets BiOI-Graphene composite visible light catalyst after the drying.

The present invention compared with prior art has following remarkable advantage:

1, in one-step method hydro-thermal building-up process, the formation of the reduction of graphene oxide and BiOI crystal is accomplished simultaneously, and preparation technology is simple;

2, need not use other chemical reducing agent, the environmental protection of preparation process economy;

3, the BiOI-graphen catalyst of preparation has very high visible light catalysis activity, in utilizing solar energy photocatalytic decomposing organic pollutant treatment technology, has potential using value.

Description of drawings

Fig. 1 is X-ray diffraction (XRD) figure of embodiment 1,2,3.

Fig. 2 is height explanation transmission electron microscope (HRTEM) figure of embodiment 1.

Fig. 3 is ultraviolet-visible (UV-Vis) absorption spectrum of embodiment 1,2,3.

Fig. 4 is the photocatalysis performance curve of the photochemical catalyst of embodiment 1,2,3 preparations.

The specific embodiment

Existing with specific embodiment of the present invention be described in detail in after.

Embodiment 1

(1) the 0.014g graphite oxide is dispersed in the 20 ml ethanol, ultrasonic 1 h obtains the suspension of graphene oxide;

(2) under the room temperature, the 0.9701g bismuth nitrate is dissolved in the 5ml glacial acetic acid, under agitation adds 0.2998 g sodium iodide and 40 ml deionized waters again;

(3) step (1) gained suspension slowly is added drop-wise in step (2) the gained solution;

(4) with behind step (3) gained solution stirring 2 h, transfer in the autoclave of teflon gasket, at 120 ℃ of following crystallization 6 h;

(5) solid product that obtains washs through filtering, drying, and obtaining Graphene content is the BiOI-Graphene composite visible light catalyst of 2.0 wt.%.

The XRD analysis result is referring to Fig. 1, and that all diffraction maximums are corresponding among the figure all is BiOI (JCPDS 10-0445) of cubic phase, in 2 θ=10.7 ^oThe characteristic diffraction peak of the graphite oxide at place disappears, and explains that hydro-thermal reaction when generating BiOI, is reduced into Graphene with graphite oxide effectively.The HRTEM result of Fig. 2 shows that it is laminar that BiOI and Graphene all are, and contact is tight between two lamellas.The uv-visible absorption spectra of sample (Fig. 3) is the result show, after BiOI and Graphene are compound, obviously increased absorption of visible light.Composite photo-catalyst visible light degradation rate to methyl orange in 4 h of preparation reaches 88%, is 3.2 times (Fig. 4) of pure BiOI.

Embodiment 2

Operating process is except that following difference, and all the other are with embodiment 1.

The 0.007g graphite oxide is dispersed in the 20 ml ethanol ultrasonic 1 h.Finally making Graphene content is the BiOI-Graphene composite visible light catalyst of 1.0 wt.%.

The XRD result of sample is referring to Fig. 1, and uv-visible absorption spectra is referring to Fig. 3, and photocatalysis performance is referring to Fig. 4.

Embodiment 3

Operating process is except that following difference, and all the other are with embodiment 1.

The 0.022g graphite oxide is dispersed in the 20 ml ethanol ultrasonic 1 h.Graphene content is the BiOI-Graphene composite visible light catalyst of 3.0 wt.%.

The XRD result of sample is referring to Fig. 1, and uv-visible absorption spectra is referring to Fig. 3, and photocatalysis performance is referring to Fig. 4.

Claims (2)

1. a BiOI-Graphene composite visible light catalyst is characterized in that, is made up of BiOI and Graphene, and it is laminar that BiOI and Graphene all are, and the mass percent of Graphene is 1.0 %-3.0 %.

2. a method for preparing BiOI-Graphene composite visible light catalyst is characterized in that, has following preparation process and step:

(a) 0.007-0.022 g graphite oxide is dispersed in the 15-25 ml ethanol, abundant ultrasonic 1-2 h obtains the suspension of graphene oxide;

(b) under the room temperature, the bismuth nitrate of 0.002 mol is dissolved in the glacial acetic acid of 3-10 ml, under agitation adds sodium iodide or KI and the 10-50 ml deionized water of 0.002 mol again;

(c) step (a) gained suspension slowly is added drop-wise in step (b) the gained solution;

(d) with behind step (c) gained solution stirring 2 h, transfer in the autoclave of teflon gasket, at 120-150 ℃ of following crystallization 6-12 h;

(e) solid product that obtains is through filtering, and washing gets BiOI-Graphene composite visible light catalyst after the drying.

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