Abstract：The rice granular CaIn2O4/In2O3was successfully synthesized via the electrospinning method using calcium nitrate and indium nitrate as the raw materials, polyvinylpyrrolidone (PVP-K30) as a template and ethanol as a solvent. The samples were characterized by X-ray diffraction (XRD),scanning electron microscope (SEM),energy spectrum analysis (EDS),transmission electron microscopy (TEM),UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and N2 adsorption-desorption isotherm. The effect of pH value and the initial concentration of methylene blue(MB) on the photocatalytic performance of CaIn2O4/In2O3 was discussed. The results show that the composites consist of orthorhombic CaIn2O4 and cubic In2O3, with particle size of (650±140) nm, energy gap of 3.48 eV and specific surface area of 17.2 m2·g-1. The degradation rate of MB reaches 92% when it is irradiated by simulated sunlight for 120 min and the photocatalysis degradation process fits the first-order kinetic model. Meanwhile, CaIn2O4/In2O3 has an excellent reusability and stability. The coupling of CaIn2O4 and In2O3 enables the photogenerated carriers to be effectively separated and therefore produces CaIn2O4/In2O3 composites with excellent photocatalytic performance.
 LING L L,FENG Y W,LI H,et al.Microwave induced surface enhanced pollutant adsorption and photocatalytic degradation on Ag/TiO2[J].Applied Surface Science,2019,483:772-778.
 YU C Q,TONG Z,LI S H,et al.Enhancing the photocatalytic activity of ZnO by using tourmaline[J].Materials Letters,2019,240:161-164.
 NIEN Y T,HSUAN C Y,CHEN I G.Solution growth of Cu2S nanowalls on Cu substrates and their characterization[J].Materials Letters,2011,65:1201-1203.
 CAO Q,CHE R C,CHEN N.Scalable synthesis of Cu2S double-superlattice nanoparticle systems with enhanced UV/visible-light-driven photocatalytic activity[J].Applied Catalysis B:Environmental,2015,162:187-195.
 YAN Y X,YANG H,ZHAO X X,et al.Enhanced photocatalytic activity of surface disorder-engineered CaTiO3[J].Materials Research Bulletin,2018,105:286-290.
 LIN Y,LU C G,WEI C Y.Microstructure and photocatalytic performance of BiVO4 prepared by hydrothermal method[J].Journal of Alloys and Compounds,2019,781:56-63.
 FENG J,ZHANG Z Q GAO M M,et al.Effect of the solvents on the photocatalytic properties of ZnFe2O4 fabricated by solvothermal method[J].Materials Chemistry and Physics,2019,223:758-761.
 XIA Y M,HE Z M,SU J B,et al.Polyacrylamide gel synthesis and photocatalytic performance of PbBiO2Br nanosheets[J].Materials Letters,2019,241:64-67.
 LI Y,XIAO X Y,YE Z H.Fabrication of BiVO4/RGO/Ag3PO4 ternary composite photocatalysts with enhanced photocatalytic performance[J].Applied Surface Science,2019,467/468:902-911.
 QIN R,MENG F M,KHAN M W,et al.Fabrication and enhan-ced photocatalytic property of TiO2-ZnO composite photocatalysts[J].Materials Letters,2019,240:84-87.
 CHANG W K,RAO K K,KUO H,et al.A novel core-shell like composite In2O3@CaIn2O4 for enhance degradation of methylene blue by visible light[J].Appllied Catalysis A:General,2007,321:1-6.
 TANG J W,ZOU Z G,KATAGIRI M,et al.Photocatalytic degradation of MB on MIn2O4 (M=alkali earth metal) under visible light:effects of crystal and electronic structure on the photocatalytic activity[J].Catalysis Today,2004,93/95:885-889.
 张俭,周艳,陈胜,等.溶胶-凝胶自蔓延燃烧法制备CaIn2O4可见光催化剂研究[J].高校化学工程学报,2009,23(1):105-109. ZHANG J,ZHOU Y,CHEN S,et al.Synthesis of the visible light photocatalyst CaIn2O4 by sol-gel auto combustion method[J].Journal of Chemical Engineering of Chinese Universities,2009,23(1):105-109.
 DING J J,SUN S,BAO J,et al.Synthesis of CaIn2O4 rods and its photocatalytic performance under visible-light irradiation[J].Catalysis Letters,2009,130:147-153.
 戈磊,张宪华.新型可见光活性In2O3-CaIn2O4复合光催化剂的制备及性能[J].硅酸盐学报,2009,37(6):981-986. GE L,ZHANG X H.Preparation and photocatalytic performance of novel In2O3-CaIn2O4 visible-light-driven composite photocatalysts[J].Journal of the Chinese Ceramic Society,2009,37(6):981-986.
 TAVARES M T S,MELO M M,ARAJÚO V D,et al.Enhancement of the photocatalytic activity and white emission of CaIn2O4nanocrystals[J].Journal of Alloys Compound,2016,658:316-323.
 DU Q C,MA J Q,SHAO X Z,et al.Core-shell structured TiO2@In2O3 for highly active visible-light photocatalysis[J].Chemical Physics Letters,2019,714:208-212.
 SU F Y,ZHANG W D.Fabrication and photoelectrochemical property of In2O3/ZnO composites nanotube arrays using ZnO nanorods as self-sacrificing templates[J].Materials Letters,2018,211:65-68.
 ZHANG Q K,ZHOU J H,DAI Q L,et al.Enhance visible-light photocatalytic activity of one dimensional In2O3/In2TiO5 nanobelts[J].Materials Research Bulletin,2019,113:102-108.
 KHAN M A M,KHAN W,AHAMED M,et al.Structural and optical properties of In2O3 nanostructured thin film[J].Materials Letters,2012,79:119-121.
 PREVÉY P S.X-ray diffraction characterization of crystallinity and phase composition in plasma-sprayed hydroxylapatite coa-tings[J]. Journal of Thermal Spray Technology,2000,9:369-376.
 GUO X M,DONG X T,WANG J X,et al.Fabrication of novel La2O2CN2 one-dimensional nanostructures via facile electrospi-nning combined with cyanamidation technique[J].Chemical Engineering Journal,2014,250:148-156.
 YANG G R,WANG L,WANG J N,et al.Fabrication and formation mechanism of Li2MnO3 ultrathin porous nanobelts by electrospinning[J].Ceramics International,2017,43(1):71-76.
 DALI S E,SUNDAR V S,CHOCKALINGAM M J.Synthesis and characterization of AIn2O4 indates,A=Mg,Ca,Sr,Ba[J].Journal of Materials Science Letters,1998,17:619-623.
 SING K S W,EVERETT D H,HAUL R A W,et al.Reporting physisorption data for gas/soil systems with special reference to the determination of the surface area and porosity[J].Pure and Appllied Chemistry,1985,57:603-619.
 LI X X,WAN T,QIU J Y,et al.In-situ photocalorimetry-fluorescence spectroscopy studies of RhB photocatalysis over Z-scheme g-C3N4@Ag@Ag3PO4 nanocomposites:a pseudo-zero-order rather than a first-order process[J].Applied Catalysis B:Environmental,2017,217:591-602.
 SHAMSIPUR M,RAJABI H R.Study of photocatalytic activity of ZnS quantum dots as efficient nanoparticles for removal of methyl violet:effect of ferric ion doping[J].Spectrochimical Acta Part:A,2014,122:260-267.
 ZHANG H J,WU W X,LI Y,et al.Enhanced photocatalytic degradation of ciprofloxacin using novel C-dot@nitrogen deficient g-C3N4:synergistic effect of nitrogen defects and C-dots[J].Applied Surface Science,2019,465:450-458.
 FERNÁNDEZ L,GAMALLO M,GONZÁLEZ-GóMEZ M A,et al. Insight into antibiotics removal:exploring the photocatalytic performance of a Fe3O4/ZnO nanocomposite in a novel magnetic sequential batch reactor[J].Journal of Environmental Management,2019,237:595-608.