天然针铁矿与合成针铁矿半导体性能对比
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摘要
利用X射线衍射仪、透射电子显微镜、X射线荧光光谱仪、X射线吸收谱与发射谱仪、光电子发射谱仪,首次对天然针铁矿与合成针铁矿样品开展了矿物学和半导体性能的对比研究。测试结果表明,天然针铁矿样品中混有少量石英颗粒,且针铁矿晶体中存在Al替代现象,Al掺杂比例为1. 16wt%～3. 23wt%。天然针铁矿禁带宽度为2. 25 eV,小于合成针铁矿2. 55 eV的带隙宽度。绝对真空能级下,天然针铁矿的价带位置为-5. 06 eV,相对于合成针铁矿有所抬升(-5. 38 eV),推测是由于Al元素替代导致在天然针铁矿价带引入Al-2p轨道成分所致。室内甲基橙降解实验结果表明天然针铁矿光催化降解甲基橙的效率(67. 2%)要高于合成针铁矿(50. 6%),表明天然针铁矿具有更好的光催化活性。天然针铁矿相较于合成材料而言具有储量高、价格低、光响应范围宽广等特点,研究结果可为进一步拓展其在材料领域的应用提供理论基础。
Natural goethite sample was collected from Anhui Tonling deposit,and measurements including powder X-ray diffraction,transmission electron microscope,X-ray fluorescence,synchrotron-based O K-edge X-ray absorption and emission spectra and photoelectron spectrometer were employed to study its mineralogical characteristics and semiconducting properties. Photocatalytic degradation of methyl orange was also carried out using natural and synthetic goethite. Results demonstrate that Al can substitute Fe in natural goethite crystal with a doping amount of 1. 16 wt% to 3. 23 wt%. The band gap of natural goethite and synthetic goethite is 2. 25 eV and 2. 55 eV,respectively. The valence band potential of natural goethite(-5. 06 eV) is slightly lifted when compared with that of synthetic goethite(-5. 38 eV),which may be caused by the incorporation of Al-2 p orbits in its valence band.Furthermore,natural goethite displays better performance (67. 2%) in photocatalytic degradation of methyl orange than synthetic goethite (50. 6%) due to its broad responding wavelength range. Natural goethite possesses many advantages over synthetic materials such as its abundant storage,lower price and better responding capability to solar light. The results can provide theoretical support for its application in the field of semiconducting materials.
Natural goethite sample was collected from Anhui Tonling deposit,and measurements including powder X-ray diffraction,transmission electron microscope,X-ray fluorescence,synchrotron-based O K-edge X-ray absorption and emission spectra and photoelectron spectrometer were employed to study its mineralogical characteristics and semiconducting properties. Photocatalytic degradation of methyl orange was also carried out using natural and synthetic goethite. Results demonstrate that Al can substitute Fe in natural goethite crystal with a doping amount of 1. 16 wt% to 3. 23 wt%. The band gap of natural goethite and synthetic goethite is 2. 25 eV and 2. 55 eV,respectively. The valence band potential of natural goethite(-5. 06 eV) is slightly lifted when compared with that of synthetic goethite(-5. 38 eV),which may be caused by the incorporation of Al-2 p orbits in its valence band.Furthermore,natural goethite displays better performance (67. 2%) in photocatalytic degradation of methyl orange than synthetic goethite (50. 6%) due to its broad responding wavelength range. Natural goethite possesses many advantages over synthetic materials such as its abundant storage,lower price and better responding capability to solar light. The results can provide theoretical support for its application in the field of semiconducting materials.
引文
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7 Liu T,Broecker W S.Millennial-scale varnish microlamination dating of late pleistocene geomorphic features in the drylands of western USA[J].Geomorphology,2013,187:38-60
8丁振华,冯俊明.氧化铁矿物对重金属离子的吸附及其表面特征[J].矿物学报,2000,20(4):349-352Ding Zhenhua,Feng Junming.Surface characteristics of iron(hydr)oxides and their adsorption of heavy metal ions[J].Acta Mineralogica Sinica,2000,20(4):349-352
9李风玲.长江三角洲地区土壤中铁氧化物对重金属的富集作用[D].南京:南京大学,2011Li Fengling.Accumulation of heavy metals on iron oxides in the soils of Yangtze River Delta[D].Nanjing:Nanjing University,2011
10 Sherman D M.Electronic structures of iron(III)and manganese(IV)(hydr)oxide minerals:thermodynamics of photochemical reductive dissolution in aquatic environments[J].Geochimica et Cosmochimica Acta,2005,69:3249-3255
11 Georgiou C D,Sun H J,Mckay C P,et al.Evidence for photochemical production of reactive oxygen species in desert soils[J].Nature Communication,2015,6:7100
12 Lan S,Wang X,Xiang Q,et al.Mechanisms of Mn(II)catalytic oxidation on ferrihydrite surfaces and the formation of manganese(oxyhydr)oxides[J].Geochimica et Cosmochimica Acta,2017,211:79-96
13孙振亚,祝春水,龚文琪.铁(氢)氧化物矿物对有机污染物的光催化氧化作用[J].矿物学报,2003,23(4):341-348Sun Zhenya,Zhu Chunshui,Gong Wenqi.Photocatalysis of organic contaminants by iron(hydr)oxide minerals in water[J].Acta Mineralogica Sinica,2003,23(4):341-348
14刘诗贝,徐亮,陈平,等.铜陵新桥矿田褐铁矿矿物组成及成因[J].岩石矿物学杂志,2016,35(3):531-542Liu Shibei,Xu Liang,Chen Ping,et al.Mineralogy of the limonite ore from the Xinqiao sulfide iron deposit in the Tongling ore concentration area of Anhui Province and its implications[J].Acta Petrologica et Mineralogica.2016,35(3):531-542
15 Fitzpatrick R W,Schwertmann U.Al-substituted goethite-an indicator of pedogenic and other weathering environments in South Africa[J].Geoderma,1982,27:335-347
16 Ruan H D,Gilkes R J.Dehydroxylation of aluminous goethite:unit cell dimensions,crystal size and surface area[J].Clays and Clay Minerals,1995,43:196-211
17 Xu Y,Schoonen M A A.The absolute energy positions of conduction and valence bands of selected semiconducting minerals[J].American Mineralogist,2000,85:543-556
18 Scanlon D O,Dunnill C W,Buckeridge J,et al.Band alignment of rutile and anatase Ti O2[J].Nature Materials,2013,12:798-801
19 Umebayashi T,Yamaki T,Itoh H,et al.Analysis of electronic structures of 3D transition metal-doped Ti O2based on band calculations[J].Journal of Physics&Chemistry of Solids,2002,63:1909-1920
20 Morgan B J,Watson G W.A density functional theory+U study of oxygen vacancy formation at the(110),(100),(101),and(001)surfaces of rutile Ti O2[J].Journal of Physical Chemistry C,2009,113:7322-7328
21丁聪,李艳,李岩,等.同步辐射软X射线吸收谱与发射谱测定天然针铁矿能带结构[J].岩石矿物学杂志,2016,35(2):349-354Ding Cong,Li Yan,Li Yan,et al.Electronic structure of natural goethite probed by soft X-ray emission and absorption spectroscopy[J].Acta Petrologica et Mineralogica.2016,35(2):349-354
2 Dorn R I.Rock varnish[J].American Scientist,1991,79:542-553
3 Huang L,Hong J,Tan W F,et al.Characteristics of micromorphology and element distribution of iron-manganese cutans in typical soils of subtropical China[J].Geoderma,2008,146:40-47
4 Huang L,Liu F,Tan W F,et al.Geochemical characteristics of selected elements in iron-manganese cutans and matrices of Alfisols in central China[J].Journal of Geochemical Exploration,2009,103:30-36
5邓景,胡火炎,李浩呜.我国南方风化淋滤型铁矿地质特征与成矿条件[J].大地构造与成矿学,1979(2):13-34Deng Jing,Hu Huoyan,Li Haowu.Geological features and minerogenetic conditions of leached iron ore in south China[J].Geotectonica et Metallogenia,1979(2):13-34
6关广岳.风化淋滤型富铁矿床的地球化学[J].地质与勘探,1976,8(8):8-17Guan Guangyue.Geochemical features of leached iron ore[J].Geology and Prospecting,1976,8(8):8-17
7 Liu T,Broecker W S.Millennial-scale varnish microlamination dating of late pleistocene geomorphic features in the drylands of western USA[J].Geomorphology,2013,187:38-60
8丁振华,冯俊明.氧化铁矿物对重金属离子的吸附及其表面特征[J].矿物学报,2000,20(4):349-352Ding Zhenhua,Feng Junming.Surface characteristics of iron(hydr)oxides and their adsorption of heavy metal ions[J].Acta Mineralogica Sinica,2000,20(4):349-352
9李风玲.长江三角洲地区土壤中铁氧化物对重金属的富集作用[D].南京:南京大学,2011Li Fengling.Accumulation of heavy metals on iron oxides in the soils of Yangtze River Delta[D].Nanjing:Nanjing University,2011
10 Sherman D M.Electronic structures of iron(III)and manganese(IV)(hydr)oxide minerals:thermodynamics of photochemical reductive dissolution in aquatic environments[J].Geochimica et Cosmochimica Acta,2005,69:3249-3255
11 Georgiou C D,Sun H J,Mckay C P,et al.Evidence for photochemical production of reactive oxygen species in desert soils[J].Nature Communication,2015,6:7100
12 Lan S,Wang X,Xiang Q,et al.Mechanisms of Mn(II)catalytic oxidation on ferrihydrite surfaces and the formation of manganese(oxyhydr)oxides[J].Geochimica et Cosmochimica Acta,2017,211:79-96
13孙振亚,祝春水,龚文琪.铁(氢)氧化物矿物对有机污染物的光催化氧化作用[J].矿物学报,2003,23(4):341-348Sun Zhenya,Zhu Chunshui,Gong Wenqi.Photocatalysis of organic contaminants by iron(hydr)oxide minerals in water[J].Acta Mineralogica Sinica,2003,23(4):341-348
14刘诗贝,徐亮,陈平,等.铜陵新桥矿田褐铁矿矿物组成及成因[J].岩石矿物学杂志,2016,35(3):531-542Liu Shibei,Xu Liang,Chen Ping,et al.Mineralogy of the limonite ore from the Xinqiao sulfide iron deposit in the Tongling ore concentration area of Anhui Province and its implications[J].Acta Petrologica et Mineralogica.2016,35(3):531-542
15 Fitzpatrick R W,Schwertmann U.Al-substituted goethite-an indicator of pedogenic and other weathering environments in South Africa[J].Geoderma,1982,27:335-347
16 Ruan H D,Gilkes R J.Dehydroxylation of aluminous goethite:unit cell dimensions,crystal size and surface area[J].Clays and Clay Minerals,1995,43:196-211
17 Xu Y,Schoonen M A A.The absolute energy positions of conduction and valence bands of selected semiconducting minerals[J].American Mineralogist,2000,85:543-556
18 Scanlon D O,Dunnill C W,Buckeridge J,et al.Band alignment of rutile and anatase Ti O2[J].Nature Materials,2013,12:798-801
19 Umebayashi T,Yamaki T,Itoh H,et al.Analysis of electronic structures of 3D transition metal-doped Ti O2based on band calculations[J].Journal of Physics&Chemistry of Solids,2002,63:1909-1920
20 Morgan B J,Watson G W.A density functional theory+U study of oxygen vacancy formation at the(110),(100),(101),and(001)surfaces of rutile Ti O2[J].Journal of Physical Chemistry C,2009,113:7322-7328
21丁聪,李艳,李岩,等.同步辐射软X射线吸收谱与发射谱测定天然针铁矿能带结构[J].岩石矿物学杂志,2016,35(2):349-354Ding Cong,Li Yan,Li Yan,et al.Electronic structure of natural goethite probed by soft X-ray emission and absorption spectroscopy[J].Acta Petrologica et Mineralogica.2016,35(2):349-354
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