Synthesis, evaluation of kinetic characteristics and investigation of apoptosis of Cu~(2+)-modified ceria nano discs
|
摘要
Ceria nano discs were synthesized by the stepwise thermal decomposition strategy of the oxalate precursor. A series of Ce_(1-x)Cu_xO_2(x = 0, 0.02, 0.1, 0.2 and 0.3) nano sized oxide systems were prepared through thermal decomposition route. Kinetic characterization of formation of solid solution was made by isoconversional strategy under non-isothermal condition. Introduction of various reactant molar ratios of Cu~(2+):Ce~(4+) has a pivotal role in the creation of new oxygen vacancies, decomposition strategy,particle size and shape. Cu~(2+) doping(x = 0.02 and 0.1) damages the disc shaped morphology of ceria.Homogeneous distribution of Cu~(2+) on the oxalate precursor has a significant role in the catalyzing activity for the destruction of oxalate bond to oxide. 2 mol% doped Cu2+ promotes breaking of oxalate bonds in nitrogen atmosphere. In vitro cell viability assay illustrates enhanced toxicity to cancer cells with 10 mol% Cu~(2+) doped ceria.
Ceria nano discs were synthesized by the stepwise thermal decomposition strategy of the oxalate precursor. A series of Ce_(1-x)Cu_xO_2(x = 0, 0.02, 0.1, 0.2 and 0.3) nano sized oxide systems were prepared through thermal decomposition route. Kinetic characterization of formation of solid solution was made by isoconversional strategy under non-isothermal condition. Introduction of various reactant molar ratios of Cu~(2+):Ce~(4+) has a pivotal role in the creation of new oxygen vacancies, decomposition strategy,particle size and shape. Cu~(2+) doping(x = 0.02 and 0.1) damages the disc shaped morphology of ceria.Homogeneous distribution of Cu~(2+) on the oxalate precursor has a significant role in the catalyzing activity for the destruction of oxalate bond to oxide. 2 mol% doped Cu2+ promotes breaking of oxalate bonds in nitrogen atmosphere. In vitro cell viability assay illustrates enhanced toxicity to cancer cells with 10 mol% Cu~(2+) doped ceria.
Ceria nano discs were synthesized by the stepwise thermal decomposition strategy of the oxalate precursor. A series of Ce_(1-x)Cu_xO_2(x = 0, 0.02, 0.1, 0.2 and 0.3) nano sized oxide systems were prepared through thermal decomposition route. Kinetic characterization of formation of solid solution was made by isoconversional strategy under non-isothermal condition. Introduction of various reactant molar ratios of Cu~(2+):Ce~(4+) has a pivotal role in the creation of new oxygen vacancies, decomposition strategy,particle size and shape. Cu~(2+) doping(x = 0.02 and 0.1) damages the disc shaped morphology of ceria.Homogeneous distribution of Cu~(2+) on the oxalate precursor has a significant role in the catalyzing activity for the destruction of oxalate bond to oxide. 2 mol% doped Cu2+ promotes breaking of oxalate bonds in nitrogen atmosphere. In vitro cell viability assay illustrates enhanced toxicity to cancer cells with 10 mol% Cu~(2+) doped ceria.
引文
1.Sun CW,Li H,Zhang HR,Wang ZX.Controlled synthesis of CeO_2 nanorods by a solvothermal method.Nanotechnology.2005;16:1454.
2.Trovarelli A.Catalytic properties of ceria and CeO_2-containing materials.Catal Rev Sci Eng.1996;38:439.
3.Laha SC,Ryoo R.Synthesis of thermally stable mesoporous cerium oxide with nano crystalline frameworks using mesoporous silica templates.Chem Commun.2003;17:2138.
4.Larachi F,Pierre J,Adnot A,Bernis A.Ce 3d XPS study of composite Ce_xMn_(1 x)O_(2 y)wet oxidation catalyst.Appl Surf Sci.2002;195:236.
5.Qiu N,Zhang J,Wu ZY,Hu TD,Liu P.Tuning ceria nano crystals morphology and structure by copper doping.Cryst Growth Des.2012;12:629.
6.Sun YG,Xia YN.Shape-controlled synthesis of gold and silver nanoparticles.Science.2002;298:2176.
7.Park J,An K,Hwang Y,Park JG,Noh HJ,Kim JY,et al.Ultra-large-scale syntheses of monodisperse nano crystals.Nat Mater.2004;3:891.
8.Guo L,Ji YL,Xu H,Simon P,Wu Z.Regularly shaped,single-crystalline ZnO nanorods with wurtzite structure.J Am Chem Soc.2002;124:14864.
9.Yang F,Wei JJ,Liu W,Guo JX,Yang YZ.Copper doped ceria nanospheres:surface defects promoted catalytic activity and a versatile approach.J Mater Chem A.2014;2:5662.
10.Carrettin S,Concepcion P,Corma A,Nieto JML,Puntes VF.Nano crystalline CeO_2increases the activity of Au for CO oxidation by two orders of magnitude.Angew Chem Int Ed.2004;43:2538.
11.Mai HX,Sun LD,Zhang YW,Si R,Feng W,Zhang HP,et al.Shape-selective synthesis and oxygen storage behavior of ceria nano polyhedra,nanorods,and nanocubes.J Phys Chem B.2005;109:24380.
12.Nolan M,Parker SC,Watson GW.The electronic structure of oxygen vacancy defects at the low index surfaces of ceria.Surf Sci.2005;595:223.
13.Alikin EA,Vedyagin AA.High temperature interaction of rhodium with oxygen storage component in three-way catalysts.Top Catal.2016;59:1033.
14.Li CL,Gu X,Wang YQ,Wang YJ,Wang YG,Liu XH,et al.Synthesis and characterization of mesostructured ceria-zirconia solid solution.J Rare Earths.2009;27:211.
15.Fan J,Wu XD,Yang L,Weng D.The SMSI between supported platinum and CeO_2-ZrO_2-La_2O_3 mixed oxides in oxidative atmosphere.Catal Today.2007;126:303.
16.Dong F,Tanabe T,Suda A,Takahashi N,Sobukawa H,Shinjoh H.Investigation of the OSC performance of Pt/CeO_2-ZrO_2-Y_2O_3 catalysts by CO oxidation and~(18)O/~(16)O isotopic exchange reaction.Chem Eng Sci.2008;63:5020.
17.He XK,Sun JL,Huan YF,Hu J,Yang DX.Influence of Al_2O_3/CeZrAl composition on the catalytic behavior of Pd/Rh catalyst.J Rare Earths.2010;28:59.
18.Fernandez-GarcíM,Martinex-Arias A,Iglesias-Juez A,Belver C,HungríAB,Conesa JC,et al.Contributions of surface and bulk heterogeneities to the NO oxidation activities of ceria-zirconia catalysts with composition Ce_(0.76)Zr_(0.24)O_2prepared by different methods.J Catal.2000;194:385.
19.Moreno M,Bergamini L,Baronetti GT,Laborde MA,Marino FJ.Mechanism of CO oxidation over CuO/CeO_2 catalysts.Int J Hydrogen Energy.2010;35:5918.
20.Desyatykh IV,Vedyagin AA,Mishakov IV,Shubin YV.CO oxidation over fiber glasses with doped Cu-Ce-O catalytic layer prepared by surface combustion synthesis.Appl Surf Sci.2015;349:21.
21.Desyatykh IV,Vedyagin AA,Kotolevich YS,Tsyrul'nikov PG.Preparation of CuO-CeO_2 catalysts deposited on glass cloth by surface self-propagating thermal synthesis.Combust Explos Shock Waves.2011;47:677.
22.Park PW,Ledford JS.The influence of surface structure on the catalytic activity of cerium promoted copper oxide catalysts on alumina:oxidation of carbon monoxide and methane.Catal Lett.1998;50:41.
23.Lara-López Y,García-Rosales G,Jimenez-Becerril J.Synthesis and characterization of carbon-TiO_2-CeO_2 composites and their applications in phenol degradation.J Rare Earths.2017;35:551.
24.Cao YY,Liu CB,Qian JC,Chen ZG,Chen F.Novel 3D porous graphene decorated with Co_3O_4/CeO_2 for high performance supercapacitor power cell.J Rare Earths.2017;35:995.
25.Wicki A,Witzigmann D,Balasubramanian V,Huwyler J.Nano medicine in cancer therapy:challenges,opportunities,and clinical applications.J Contr Release.2015;200:138.
26.Hochella Jr MF,Lower SK,Maurice PA,Penn RL,Sahai N,Sparks DL,et al.Nano minerals,mineral nanoparticles,and earth systems.Science.2008;319:1631.
27.Yu JC,Zhang LZ,Lin J.Direct sonochemical preparation of high-surface-area nanoporous ceria and ceria-zirconia solid solutions.J Colloid Interface Sci.2003;260:240.
28.Carl W,Soumen D,Sudipta S,Joseph E,Karin H,Lina G,et al.Catalytic properties and biomedical applications of cerium oxide nanoparticles.Environ Sci Nano.2015;2:33.
29.Gao Y,Chen K,Ma JL,Gao F.Cerium oxide nanoparticles in cancer.Onco Targets Ther.2014;7:835.
30.Wason MS,Colon J,Das S,Seal S,Turkson J,Zhao J,et al.Sensitization of pancreatic cancer cells to radiation by cerium oxide nanoparticle-induced ROS production.Nanomedicine.2013;9:558.
31.Grulke E,Kenneth R,Matthew B,Xing H,Alastair C,Sudipta S.Nanoceria:factors affecting its pro-and anti-oxidant properties.Environ Sci Nano.2014;1:429.
32.Amit K,Soumen D,Prabhakaran M,William S,Donald RB,Dean CS,et al.Behavior of nanoceria in biologically-relevant environments.Environ Sci Nano.2014;1:516.
33.Asati A,Santra S,Kaittanis C,Perez JM.Surface-charge-dependent cell localization and cytotoxicity of cerium oxide nanoparticles.ACS Nano.2010;4:5321.
34.Alili L,Sack M,von Montfort C,Giri S,Das S,Carroll KS,et al.Downregulation of tumor growth and invasion by redox-active nanoparticles.Antioxid Redox Signal.2013;19:765.
35.Wang Y,Yang F,Zhang HX,Zi XY,Pan XH,Chen F,et al.Cuprous oxide nanoparticles inhibit the growth and metastasis of melanoma by targeting mitochondria.Cell Death Dis.2013;4:783.
36.Clark A,Zhu A,Petty HR.Titanium-doped cerium oxide nanoparticles protect cells from hydrogen peroxide-induced apoptosis.J Nanopart Res.2013;15:2126.
37.Wongrakpanich A,Mudunkotuwa IA,Geary SM,Morris AS,Mapuskar KA,Spitz DR,et al.Size-dependent cytotoxicity of copper oxide nanoparticles in lung epithelial cells.Environ Sci Nano.2016;3:365.
38.Dziembaj R,Molenda M,Chmielarz L,Drozdek M,Zaitz MM,Dudek B,et al.Nanostructured cu-doped ceria obtained by reverse micro emulsion method as catalysts for incineration of selected VOCs.Catal Lett.2010;135:68.
39.Wang CH,Lin SS,Liou SB,Weng HS.The promoter effect and a rate expression of the catalytic incineration of(CH_3)_2S_2 over an improved CuO-MoO_3/gammaAl_2O_3 catalyst.Chemosphere.2002;49:389.
40.Wada T,Nakano M,Koga N.Multistep kinetic behavior of the thermal decomposition of granular sodium percarbonate:hindrance effect of the outer surface layer.J Phys Chem A.2015;119:9749.
41.Kitabayashi S,Koga N.Physico-geometrical mechanism and overall kinetics of thermally induced oxidative decomposition of tin(II)oxalate in air:formation process of micro structural tin(IV)oxide.J Phys Chem C.2014;118:17847.
42.Yoshikawa M,Yamada S,Koga N.Phenomenological interpretation of them thermal decomposition of silver carbonate to form silver metal.J Phys Chem C.2014;118:8059.
43.Koga N,Goshi Y,Yamada S,Perez-Maqueda LA.Kinetic approach to partially overlapped thermal decomposition processes:co-precipitated zinc carbonates.J Therm Anal Calorim.2013;111:1463.
44.Nusrath K,Muraleedharan K.Effect of Ca(II)on the multistep kinetic behavior of thermally induced oxidative decomposition of cerium(III)oxalate to CeO_2(IV).J Anal Appl Pyrol.2016;120:379.
45.Ozawa T.Applicability of friedman plot.J Therm Anal.1986;31:547.
46.Koga N.Kinetic analysis of thermoanalytical data by extrapolating to infinite temperature.Thermochim Acta.1995;258:145.
47.Gotor FJ,Criado JM,Malek J,Koga N.Kinetic analysis of solid-state reactions:the universality of master plots for analyzing isothermal and non-isothermal experiments.J Phys Chem A.2000;104:10777.
48.Adamopoulos O.Royal Institute of Technology,Stockholm;2003.
49.Askrabic S,Dohcevic-Mitrovic ZD,Araújo VD,Ionita G,de Lima Jr MM,Cantarero A.F-centre luminescence in nanocrystalline CeO_2.J Phys D Appl Phys.2013;46:495306.
50.Sudarshan K,Sharma SK,Gupta R,Gupta SK,Sayed FN,Pujari PK.Role of surface defects in catalytic properties of CeO_2 nanoparticles towards oxygen reduction reaction.Mater Chem Phys.2017;200:99.
51.Gamarra D,Munuera G,Hungria AB,Fernandez-Garcia M,Conesa JC,Midgley PA,et al.Structure-activity relationship in nanostructured copper-ceria-based preferential CO oxidation catalysts.J Phys Chem C.2007;111:11026.
52.Martinez-Arias A,Sofia J,Catalu R,Conesa JC,Corberan VC.Influence of ceria dispersion on the catalytic performance of Cu/CeO_2/Al_2O_3 catalysts for the CO oxidation reaction.Stud Surf Sci Catal.1998;116:591.
53.Weber WH,Hass KC,McBride JR.Raman study of CeO_2:second-order scattering,lattice dynamics,and particle-size effects.Phys Rev B Condens Matter.1993;48:178.
54.Spanier JE,Robinson RD,Zhang F,Chan SW,Herman IP.Size-dependent properties of CeO_2 nanoparticles as studied by Raman scattering.Phys Rev B.2001;64:245407.
55.Garda MF,Arias AM,Hanson JC,Rodriguez JA.Nanostructured oxides in chemistry:characterization and properties.Chem Rev.2004;104:4063.
56.McBride JR,Hass KC,Poindexter BD,Weber WH.Raman and X-ray studies of Ce_(1 x)RE_xO_(2 y),where RE=La,Pr,Nd,Eu,Gd,and Tb.J Appl Phys.1994;76:2435.
2.Trovarelli A.Catalytic properties of ceria and CeO_2-containing materials.Catal Rev Sci Eng.1996;38:439.
3.Laha SC,Ryoo R.Synthesis of thermally stable mesoporous cerium oxide with nano crystalline frameworks using mesoporous silica templates.Chem Commun.2003;17:2138.
4.Larachi F,Pierre J,Adnot A,Bernis A.Ce 3d XPS study of composite Ce_xMn_(1 x)O_(2 y)wet oxidation catalyst.Appl Surf Sci.2002;195:236.
5.Qiu N,Zhang J,Wu ZY,Hu TD,Liu P.Tuning ceria nano crystals morphology and structure by copper doping.Cryst Growth Des.2012;12:629.
6.Sun YG,Xia YN.Shape-controlled synthesis of gold and silver nanoparticles.Science.2002;298:2176.
7.Park J,An K,Hwang Y,Park JG,Noh HJ,Kim JY,et al.Ultra-large-scale syntheses of monodisperse nano crystals.Nat Mater.2004;3:891.
8.Guo L,Ji YL,Xu H,Simon P,Wu Z.Regularly shaped,single-crystalline ZnO nanorods with wurtzite structure.J Am Chem Soc.2002;124:14864.
9.Yang F,Wei JJ,Liu W,Guo JX,Yang YZ.Copper doped ceria nanospheres:surface defects promoted catalytic activity and a versatile approach.J Mater Chem A.2014;2:5662.
10.Carrettin S,Concepcion P,Corma A,Nieto JML,Puntes VF.Nano crystalline CeO_2increases the activity of Au for CO oxidation by two orders of magnitude.Angew Chem Int Ed.2004;43:2538.
11.Mai HX,Sun LD,Zhang YW,Si R,Feng W,Zhang HP,et al.Shape-selective synthesis and oxygen storage behavior of ceria nano polyhedra,nanorods,and nanocubes.J Phys Chem B.2005;109:24380.
12.Nolan M,Parker SC,Watson GW.The electronic structure of oxygen vacancy defects at the low index surfaces of ceria.Surf Sci.2005;595:223.
13.Alikin EA,Vedyagin AA.High temperature interaction of rhodium with oxygen storage component in three-way catalysts.Top Catal.2016;59:1033.
14.Li CL,Gu X,Wang YQ,Wang YJ,Wang YG,Liu XH,et al.Synthesis and characterization of mesostructured ceria-zirconia solid solution.J Rare Earths.2009;27:211.
15.Fan J,Wu XD,Yang L,Weng D.The SMSI between supported platinum and CeO_2-ZrO_2-La_2O_3 mixed oxides in oxidative atmosphere.Catal Today.2007;126:303.
16.Dong F,Tanabe T,Suda A,Takahashi N,Sobukawa H,Shinjoh H.Investigation of the OSC performance of Pt/CeO_2-ZrO_2-Y_2O_3 catalysts by CO oxidation and~(18)O/~(16)O isotopic exchange reaction.Chem Eng Sci.2008;63:5020.
17.He XK,Sun JL,Huan YF,Hu J,Yang DX.Influence of Al_2O_3/CeZrAl composition on the catalytic behavior of Pd/Rh catalyst.J Rare Earths.2010;28:59.
18.Fernandez-GarcíM,Martinex-Arias A,Iglesias-Juez A,Belver C,HungríAB,Conesa JC,et al.Contributions of surface and bulk heterogeneities to the NO oxidation activities of ceria-zirconia catalysts with composition Ce_(0.76)Zr_(0.24)O_2prepared by different methods.J Catal.2000;194:385.
19.Moreno M,Bergamini L,Baronetti GT,Laborde MA,Marino FJ.Mechanism of CO oxidation over CuO/CeO_2 catalysts.Int J Hydrogen Energy.2010;35:5918.
20.Desyatykh IV,Vedyagin AA,Mishakov IV,Shubin YV.CO oxidation over fiber glasses with doped Cu-Ce-O catalytic layer prepared by surface combustion synthesis.Appl Surf Sci.2015;349:21.
21.Desyatykh IV,Vedyagin AA,Kotolevich YS,Tsyrul'nikov PG.Preparation of CuO-CeO_2 catalysts deposited on glass cloth by surface self-propagating thermal synthesis.Combust Explos Shock Waves.2011;47:677.
22.Park PW,Ledford JS.The influence of surface structure on the catalytic activity of cerium promoted copper oxide catalysts on alumina:oxidation of carbon monoxide and methane.Catal Lett.1998;50:41.
23.Lara-López Y,García-Rosales G,Jimenez-Becerril J.Synthesis and characterization of carbon-TiO_2-CeO_2 composites and their applications in phenol degradation.J Rare Earths.2017;35:551.
24.Cao YY,Liu CB,Qian JC,Chen ZG,Chen F.Novel 3D porous graphene decorated with Co_3O_4/CeO_2 for high performance supercapacitor power cell.J Rare Earths.2017;35:995.
25.Wicki A,Witzigmann D,Balasubramanian V,Huwyler J.Nano medicine in cancer therapy:challenges,opportunities,and clinical applications.J Contr Release.2015;200:138.
26.Hochella Jr MF,Lower SK,Maurice PA,Penn RL,Sahai N,Sparks DL,et al.Nano minerals,mineral nanoparticles,and earth systems.Science.2008;319:1631.
27.Yu JC,Zhang LZ,Lin J.Direct sonochemical preparation of high-surface-area nanoporous ceria and ceria-zirconia solid solutions.J Colloid Interface Sci.2003;260:240.
28.Carl W,Soumen D,Sudipta S,Joseph E,Karin H,Lina G,et al.Catalytic properties and biomedical applications of cerium oxide nanoparticles.Environ Sci Nano.2015;2:33.
29.Gao Y,Chen K,Ma JL,Gao F.Cerium oxide nanoparticles in cancer.Onco Targets Ther.2014;7:835.
30.Wason MS,Colon J,Das S,Seal S,Turkson J,Zhao J,et al.Sensitization of pancreatic cancer cells to radiation by cerium oxide nanoparticle-induced ROS production.Nanomedicine.2013;9:558.
31.Grulke E,Kenneth R,Matthew B,Xing H,Alastair C,Sudipta S.Nanoceria:factors affecting its pro-and anti-oxidant properties.Environ Sci Nano.2014;1:429.
32.Amit K,Soumen D,Prabhakaran M,William S,Donald RB,Dean CS,et al.Behavior of nanoceria in biologically-relevant environments.Environ Sci Nano.2014;1:516.
33.Asati A,Santra S,Kaittanis C,Perez JM.Surface-charge-dependent cell localization and cytotoxicity of cerium oxide nanoparticles.ACS Nano.2010;4:5321.
34.Alili L,Sack M,von Montfort C,Giri S,Das S,Carroll KS,et al.Downregulation of tumor growth and invasion by redox-active nanoparticles.Antioxid Redox Signal.2013;19:765.
35.Wang Y,Yang F,Zhang HX,Zi XY,Pan XH,Chen F,et al.Cuprous oxide nanoparticles inhibit the growth and metastasis of melanoma by targeting mitochondria.Cell Death Dis.2013;4:783.
36.Clark A,Zhu A,Petty HR.Titanium-doped cerium oxide nanoparticles protect cells from hydrogen peroxide-induced apoptosis.J Nanopart Res.2013;15:2126.
37.Wongrakpanich A,Mudunkotuwa IA,Geary SM,Morris AS,Mapuskar KA,Spitz DR,et al.Size-dependent cytotoxicity of copper oxide nanoparticles in lung epithelial cells.Environ Sci Nano.2016;3:365.
38.Dziembaj R,Molenda M,Chmielarz L,Drozdek M,Zaitz MM,Dudek B,et al.Nanostructured cu-doped ceria obtained by reverse micro emulsion method as catalysts for incineration of selected VOCs.Catal Lett.2010;135:68.
39.Wang CH,Lin SS,Liou SB,Weng HS.The promoter effect and a rate expression of the catalytic incineration of(CH_3)_2S_2 over an improved CuO-MoO_3/gammaAl_2O_3 catalyst.Chemosphere.2002;49:389.
40.Wada T,Nakano M,Koga N.Multistep kinetic behavior of the thermal decomposition of granular sodium percarbonate:hindrance effect of the outer surface layer.J Phys Chem A.2015;119:9749.
41.Kitabayashi S,Koga N.Physico-geometrical mechanism and overall kinetics of thermally induced oxidative decomposition of tin(II)oxalate in air:formation process of micro structural tin(IV)oxide.J Phys Chem C.2014;118:17847.
42.Yoshikawa M,Yamada S,Koga N.Phenomenological interpretation of them thermal decomposition of silver carbonate to form silver metal.J Phys Chem C.2014;118:8059.
43.Koga N,Goshi Y,Yamada S,Perez-Maqueda LA.Kinetic approach to partially overlapped thermal decomposition processes:co-precipitated zinc carbonates.J Therm Anal Calorim.2013;111:1463.
44.Nusrath K,Muraleedharan K.Effect of Ca(II)on the multistep kinetic behavior of thermally induced oxidative decomposition of cerium(III)oxalate to CeO_2(IV).J Anal Appl Pyrol.2016;120:379.
45.Ozawa T.Applicability of friedman plot.J Therm Anal.1986;31:547.
46.Koga N.Kinetic analysis of thermoanalytical data by extrapolating to infinite temperature.Thermochim Acta.1995;258:145.
47.Gotor FJ,Criado JM,Malek J,Koga N.Kinetic analysis of solid-state reactions:the universality of master plots for analyzing isothermal and non-isothermal experiments.J Phys Chem A.2000;104:10777.
48.Adamopoulos O.Royal Institute of Technology,Stockholm;2003.
49.Askrabic S,Dohcevic-Mitrovic ZD,Araújo VD,Ionita G,de Lima Jr MM,Cantarero A.F-centre luminescence in nanocrystalline CeO_2.J Phys D Appl Phys.2013;46:495306.
50.Sudarshan K,Sharma SK,Gupta R,Gupta SK,Sayed FN,Pujari PK.Role of surface defects in catalytic properties of CeO_2 nanoparticles towards oxygen reduction reaction.Mater Chem Phys.2017;200:99.
51.Gamarra D,Munuera G,Hungria AB,Fernandez-Garcia M,Conesa JC,Midgley PA,et al.Structure-activity relationship in nanostructured copper-ceria-based preferential CO oxidation catalysts.J Phys Chem C.2007;111:11026.
52.Martinez-Arias A,Sofia J,Catalu R,Conesa JC,Corberan VC.Influence of ceria dispersion on the catalytic performance of Cu/CeO_2/Al_2O_3 catalysts for the CO oxidation reaction.Stud Surf Sci Catal.1998;116:591.
53.Weber WH,Hass KC,McBride JR.Raman study of CeO_2:second-order scattering,lattice dynamics,and particle-size effects.Phys Rev B Condens Matter.1993;48:178.
54.Spanier JE,Robinson RD,Zhang F,Chan SW,Herman IP.Size-dependent properties of CeO_2 nanoparticles as studied by Raman scattering.Phys Rev B.2001;64:245407.
55.Garda MF,Arias AM,Hanson JC,Rodriguez JA.Nanostructured oxides in chemistry:characterization and properties.Chem Rev.2004;104:4063.
56.McBride JR,Hass KC,Poindexter BD,Weber WH.Raman and X-ray studies of Ce_(1 x)RE_xO_(2 y),where RE=La,Pr,Nd,Eu,Gd,and Tb.J Appl Phys.1994;76:2435.