王 涵,許 倩,鄭 星,韓文清,江 波,孫冠華 ,鐘彩霞,尹華承,鄭經(jīng)堂
[1.中國石油大學(xué)(華東)重質(zhì)油國家重點(diǎn)實(shí)驗(yàn)室,山東 青島 266580;2.包頭輕工職業(yè)技術(shù)學(xué)院,內(nèi)蒙古 包頭 014045;3.北京中能環(huán)科技術(shù)發(fā)展有限公司,北京 100080]
·研究論文·
核殼型PS/CdS復(fù)合催化劑的制備及其光催化性能*
王 涵1,2,許 倩1,鄭 星3,韓文清2,江 波1,孫冠華1,鐘彩霞2,尹華承1,鄭經(jīng)堂1
[1.中國石油大學(xué)(華東)重質(zhì)油國家重點(diǎn)實(shí)驗(yàn)室,山東 青島 266580;2.包頭輕工職業(yè)技術(shù)學(xué)院,內(nèi)蒙古 包頭 014045;3.北京中能環(huán)科技術(shù)發(fā)展有限公司,北京 100080]
核-殼結(jié)構(gòu);CdS;超聲化學(xué)法;合成;光催化性能
在眾多雜化材料中,核殼結(jié)構(gòu)因其獨(dú)特的組成和排列方式,以及多重納米粒子屬性而備受科學(xué)家關(guān)注[1]。研究表明,通過設(shè)計(jì)核殼結(jié)構(gòu)的核-殼,利用兩者間的互補(bǔ)效應(yīng),可改善材料的表面及形態(tài)結(jié)構(gòu),提高材料的整體性能[2-4]。半導(dǎo)體CdS具有較窄的禁帶寬度(2.42eV)和可見光敏感性,已廣泛應(yīng)用于光電領(lǐng)域。國內(nèi)外學(xué)者通過Layer-by-Layer(LBL)[5]、微波輔助法[6]、輻照法[7]、靜電自組裝法[8,9]和原子轉(zhuǎn)移自由基聚合(ATRP)[10]等方法制備了核殼型有機(jī)/CdS材料。
Scheme 1
超聲化學(xué)法是利用超聲波引發(fā)的液-固非均勻體系反應(yīng),可有效控制晶體生長和顆粒團(tuán)聚,得到粒度分布窄的超細(xì)顆粒。由于該方法易于控制、周期短和效率高,已被用于制備包括核殼結(jié)構(gòu)在內(nèi)的多種納米單體及復(fù)合材料,如:Au/Pd[11],Au/Ag[12],PS/ZnS[13],ZnO/CdS[14],CdSe/ZnS[15],SiO2/FePt[16],ZnO/ZnS[17]和Fe3O4/SiO2[18]。
1.1 儀器與試劑
GS54T型紫外-可見分光光度計(jì)(UV-Vis);Thermo Nicolet NEXUS型紅外光譜儀;X′Pert Pro MPD型X-射線衍射儀;S4800型掃描電鏡;JEM-2100UHR型電子透射鏡。
所用試劑均為分析純,國藥集團(tuán)化學(xué)試劑有限公司;實(shí)驗(yàn)用水為自制去離子水。
1.2 合成
(1)單分散PS微球的制備[19]
N2保護(hù)下,在反應(yīng)瓶中加入水200mL,對苯乙烯磺酸鈉(SSS)35.6mg和NaHCO3140.8mg,攪拌使其混合均勻;升溫至70℃,快速加入苯乙烯(St),反應(yīng)30min;加引發(fā)劑過硫酸鉀(KPS)288.0mg,反應(yīng)28h。冷卻至室溫得PS乳液A。
不加PS乳液A,用類似的方法制得CdS。
1.3 光催化活性
在反應(yīng)瓶中加入RhB(10mg·mL-1)100mL和c(1)25.0mg,于暗室吸附反應(yīng)30min使其達(dá)到物理吸附平衡。在800W·m-2的35W氙燈冷光源照射下,每隔一定時(shí)間取樣,共反應(yīng)70min。離心,取上層清液于554nm處測定其吸光度(A)。
2.1 反應(yīng)機(jī)理
表面活性劑PVP由疏水骨架與親水側(cè)鏈組成。其結(jié)構(gòu)中無酸性質(zhì)子,但有兩個(gè)電子基中心(-C=O和吡咯環(huán))。由于N原子的空間限制,-C=O被認(rèn)為是最有利的連接位點(diǎn)[20]。因此,PVP一端的非極性亞甲基與PS聚合物接枝共聚,硫代乙酰胺(TAA)在超聲過程中緩慢釋放S2-與伸出PS粒子表面的PVP另一端極性丁內(nèi)酰胺基團(tuán)的-C=O配位鍵合,使鎘源提供的Cd2+與S2-僅在PS微球表面反應(yīng)生成CdS,直至形成均勻包覆層并逐漸增厚。PVP作為偶聯(lián)劑,通過增強(qiáng)殼層與內(nèi)核之間的相互作用,成功地將PS與CdS復(fù)合起來形成雜化的三維核殼結(jié)構(gòu)PS/CdS納米復(fù)合材料1,如Scheme 1所示。
2.2 反應(yīng)條件優(yōu)化
以1的形貌,即1的SEM和TEM照片為指標(biāo),對其反應(yīng)條件進(jìn)行優(yōu)化,尋找最佳的反應(yīng)條件。
(1)r
由此可見,PS微球表面包覆了納米CdS粒子,形成了核殼結(jié)構(gòu);當(dāng)r=1.4,可得到完整均一包覆的1,即最佳的r=1.4。
(2)t
2.3 表征
(1)FT-IR
ν/cm-1
(2)XRD
2θ/(°)
圖 5 PS和1的SEM;1的TEM和EDS譜圖Figure 5 SEM images of PS and 1,TEM and EDS patterns of 1
(3)SEM,TEM和EDS
2.4 光催化性能
Time/min
λ/nm
以乙酸鎘和硫代乙酰胺為殼層,PVP為偶聯(lián)劑,聚苯乙烯微球?yàn)閮?nèi)核,用超聲化學(xué)法制備了核殼型PS/CdS納米復(fù)合材料1。1的內(nèi)核平均粒徑約260nm,CdS殼層厚度為10nm~30nm。考察了反應(yīng)時(shí)間和物料比對1微觀形貌的影響。合成1的最佳反應(yīng)條件為:Cd(Ac)228mmol,n(Cd2+)∶n(S2-)=1.0∶1.4,聚乙烯比咯烷酮為偶聯(lián)劑超聲反應(yīng)3h。1光催化羅丹明降解反應(yīng)結(jié)果表明,70min脫色率達(dá)到100%。
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SynthesisandPhotocatalysisActivityofPS/CdSCore-ShellStructureCompositePhotocatalyst
WANG Han1,2,XU Qian1,ZHENG Xing3,HAN Wen-qing2,JIANG Bo1,SUN Guan-hua1,ZHONG Cai-xia2,YIN Hua-cheng1,ZHENG Jing-tang1
(1.State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Qingdao 255580,China;2.Baotou Light Industry and Vocational Technical College,Baotou 014045,China;Beijing ZNHK Science and Technology Development Co.,LTD,Beijing 100080,China)
A core-shell structure composite photocatalysts(PS/CdS,1)was synthesized by facile ultrasonic method,using PS as the model and PVP as the coupling agent.The structures and photocatalysis activity were characterized by UV-Vis,FT-IR,XRD,SEM,TEM and EDS.Effects of reaction time and mole ratio on the microstructure of1were investigated.The optimum reaction conditions of1were as follows: Cd(Ac)2was 28mmol,n(Cd2+)∶n(S2-)=1.0∶ 1.4and reaction time was 3h.The results of photocatalyzing RhB degradation indicated that the decolourization ratio was 100% after 70min.
core-shell structure;CdS;ultrasonic method;synthesis;photocatalysis
2014-07-10
國家自然科學(xué)基金資助項(xiàng)目(21376268,21176260);國家重點(diǎn)基礎(chǔ)研究發(fā)展計(jì)劃(973)資助項(xiàng)目(2011CB605703);泰山學(xué)者資助計(jì)劃(ts20130929)
王涵(1975-),女,漢族,內(nèi)蒙古赤峰人,博士研究生,講師,主要從事新型環(huán)保材料的研究。E-mail: wanghan960070@126.com
鄭經(jīng)堂,博士生導(dǎo)師,E-mail: jtzheng03@163.com;鄭星,E-mail: znhk113@163.com
O631.3;TQ426.6
A
1005-1511(2014)06-0725-05