[1] G IERVOLINO, I ZAMMIT, V VAIANO et al. Limitations and prospects for wastewater treatment by uv and visible-light-active heterogeneous photocatalysis: a critical review. Topics in Current Chemistry Collections(2020).

[2] C LIU. Nanophotocatalytic and photocatalytic environment purification materials(2008).

[3] L WANG, S LIU, Z WANG et al. Piezotronic effect enhanced photocatalysis in strained anisotropic ZnO/TiO2 nanoplatelets via thermal stress. ACS Nano, 10, 2636-2643(2016).

[4] Lisheng ZHANG, Hui LI, Hanxin ZHANG et al. Research progress on application and preparation of nano-zinc oxide. Hydrometallurgy of China, 2, 79-83(2019).

[5] H TIAN, H FAN, M LI et al. Zeolitic imidazolate framework coated ZnO nanorods as molecular sieving to improve selectivity of formaldehyde gas sensor. ACS Sensors, 1, 243-250(2016).

[6] L MA, H FAN, H TIAN et al. The n-ZnO/n-In2O3 heterojunction formed by a surface-modification and their potential barrier-control in methanal gas sensing. Sensors and Actuators B: Chemical, 222, 508-516(2016).

[7] X ZOU, H FAN, Y TIAN et al. Synthesis of Cu2O/ZnO hetero-nanorod arrays with enhanced visible light-driven photocatalytic activity. CrystEngComm, 16, 1149-1156(2014).

[8] P ZHANG, S ZHU, Z HE et al. Photochemical synthesis of SnO2/TiO2 composite nanotube arrays with enhanced lithium storage performance. Journal of Alloys and Compounds, 674, 1-8(2016).

[9] W XU, W JI, P JING et al. Efficient inverted quantum-dot light-emitting devices with TiO2/ZnO bilayer as the electron contact layer. Optical Society of America, 39, 426-429(2014).

[10] T D DAO, C T T DANG, G HAN et al. Chemically synthesized nanowire TiO2/ZnO core-shell p-n junction array for high sensitivity ultraviolet photodetector. Applied Physics Letters, 103, 193119(2013).

[11] A P RAMBU, L URSU, N IFTIMIE et al. Study on Ni-doped ZnO films as gas sensors. Applied Surface Science, 280, 598-604(2013).

[12] S YI, J CUI, S LI et al. Enhanced visible-light photocatalytic activity of Fe/ZnO for rhodamine B degradation and its photogenerated charge transfer properties. Applied Surface Science, 319, 230-236(2012).

[13] J J MACIAS-SANCHEZ, L HINOJOSA-REYES, A CABALLERO-QUINTERO et al. Synthesis of nitrogen-doped ZnO by sol-gel method: characterization and its application on visible photocatalytic degradation of 2,4-D and picloram herbicides. Photochemical and Photobiological Sciences, 14, 536-542(2015).

[14] Yu CHEN, Fei YU, Yutong LIU et al. Effects of different synthesis process on photocatalytic properties of ZnO/Ag nanocomposites prepared by sol-gel method. Materials Reports, 31, 120-124+140(2017).

[15] M VENKATA, P JUAN, B CORREA et al. ZnO-TiO2 nanocomposite films for high light harvesting effciency and fast electron transport in dye-sensitized solar cells. The Journal of Physical Chemistry C, 116, 23864-23870(2012).

[16] D CHEN, H ZHANG, S HU et al. Preparation and enhanced photoelectrochemical performance of coupled bicomponent ZnO-TiO2 nanocomposites. The Journal of Physical Chemistry C, 112, 117-122(2008).

[17] Zhe JIA, Shuai REN, Jiejing ZHANG et al. Fabrication and photocatalytic activity of heterojunction type CuO/ZnO composite nanowires. Acta Photonica Sinia, 50, 0150004(2021).

[18] Zhumei WANG, Yueming LI, Runhua LIAO et al. Preparation and photocatalytic properties of NiO/TiO2 nanotubes by hydrothermal method. Acta Photonica Sinica, 48, 0316003(2019).

[19] M TOBAJAS, C BELVER, J J RODRIGUEZ et al. Degradation of emerging pollutants in water under solar irradiation using novel TiO2-ZnO/clay nanoarchitectures. Chemical Engineering Journal, 309, 596-606(2016).

[20] S YUAN, J MU, R MAO et al. All-nanoparticle self-assembly ZnO/TiO2 heterojunction thin films with remarkably enhanced photoelectrochemical activity. ACS Applied Materials & Interfaces, 6, 5719-5725(2014).

[21] R ZHA, R NADIMICHERLA, X GUO et al. Ultraviolet photocatalytic degradation of methyl orange by nanostructured TiO2/ZnO heterojunctions. Journal of Materials Chemistry A, 3, 6565(2015).

[22] Yutong LIU, Xiaonan XU, Yu CHEN et al. Comparative study on the synthesis of ZnO nanocrytals by sol-gel and polymer network gel method. Journal of Synthetic Crystals, 46, 942-949(2017).

[23] Y LIU, Q ZHANG, M XU et al. Novel and efficient synthesis of Ag-ZnO nanoparticles for the sunlight-induced photocatalytic degradation. Applied Surface Science, 476, 632-640(2019).

[24] J LI, Q ZHANG, H YUAN et al. Chemically synthesized (Ag, Mn2O3)-codecorated ZnO nanoparticles for achieving superior visible photodegradation and enhanced gas sensing activity. Physical Chemistry Chemical Physics, 23, 13797-13807(2021).

[25] Hai LI, Kaiyi LUO, Wenyu HU et al. Facile synthesis of core-shell structure ZnO/g-C3N4 nano-composite with enhanced photocatalytic activity. Acta Photonica Sinia, 50, 1116001(2021).

[26] L CHENG, S QIU, J CHEN et al. A practical pathway for the preparation of Fe2O3 decorated TiO2 photocatalysts with enhanced visible-light photoactivity. Materials Chemistry and Physics, 190, 53-61(2017).

[27] H QI, H LIU, L ZHANG et al. Photodegradation of methyl orange over CdS-TiO2/L-zeolite composite photocatalyst. Journal of Inorganic and Organometallic Polymers and Materials, 29, 564-571(2019).

[28] S KANDULA, P JEEVANANDAM. Visible-light-induced photodegradation of methylene blue using ZnO/CdS heteronanostructures synthesized through a novel thermal decomposition approach. Journal of Nanoparticle Research, 16, 2452(2014).

[29] M N ISLAM, T B GHOSH, K L CHOPRA et al. XPS and X-ray diffraction studies of aluminum-doped zinc oxide transparent conducting films. Thin Solid Films, 280, 20-25(1996).

[30] T GIANNAKOPOULOU, N TODOROVA, C TRAPALIS et al. Effect of fluorine doping and SiO2 under-layer on the optical properties of TiO2 thin films. Materials Letters, 61, 4474-4477(2007).

[31] N TODOROVA, T GIANNAKOPOULOU, G ROMANOS et al. Preparation of fluorine-doped TiO2 photocatalysts with controlled crystalline structure. International Journal of Photoenergy, 534038(2008).

[32] K LUO, Q ZHANG, H YUAN et al. Facile synthesis of Ag/Zn1-xCuxO nanoparticle compound photocatalyst for high-efficiency photocatalytic degradation: insights into the synergies and antagonisms between Cu and Ag. Ceramics International, 47, 48-56(2021).

[33] Z DENG, M CHEN, G GU et al. A facile method to fabricate ZnO hollow spheres and their photocatalytic property. Journal of Physical Chemistry B, 112, 16-22(2008).

[34] Q ZHANG, M XU, B YOU et al. Oxygen vacancy-mediated ZnO nanoparticle photocatalyst for degradation of methylene blue. Applied Sciences, 8, 353(2018).

[35] Q ZHANG, C CHEN, Y LIU et al. Improved response/recovery speeds ZnO nanoparticle-based sensor toward NO2 gas under UV irradiation induced by surface. Journal of Materials Science: Materials in Electronics, 30, 11395-11403(2019).

[36] M KONG, Y LI, X CHEN et al. Tuning the relative concentration ratio of bulk defects to surface defects in TiO2 nanocrystals leads to high photocatalytic efficiency. Journal of the American Chemical Society, 133, 16414-16417(2011).

[37] Y LV, C PAN, X MA et al. Production of visible activity and UV performance enhancement of ZnO photocatalyst via vacuum deoxidation. Applied Catalysis B: Environmental, 138, 26-32(2013).

[38] Y LV, W YAO, X MA et al. The surface oxygen vacancy induced visible activity and enhanced UV activity of a ZnO1-x photocatalyst. Catalysis Science & Technology, 3, 3136-3146(2013).

[39] J TAUC, R GRIGOROVICI, A VANCU. Optical properties and electronic structure of amorphous germanium. Physica Status Solidi, 15, 627-637(1966).

[40] F ABELES. Optical properties of solids, 277-310(1972).

[41] E A DAVIS, N F MOTT. Conduction in non-crystalline systems V. Conductivity, optical absorption and photoconductivity in amorphous semiconductors. Philosophical Magazine, 22, 903-922(1970).

[42] R CHEN, F FAN, T DITTRICH et al. Imaging photogenerated charge carriers on surfaces and interfaces of photocatalysts with surface photovoltage microscopy. Chemical Society Reviews, 47, 8238-8262(2018).

[43] M MCCLUSKEY, S JOKELA. Defects in ZnO. Journal of Applied Physics, 106, 071101(2009).

[44] S BANERJEE, S C PILLAI, P FALARAS et al. New insights into the mechanism of visible light photocatalysis. The Journal of Physical Chemistry Letters, 5, 2543-2554(2014).

[45] X ZHENG, D LI, X LI et al. Construction of ZnO/TiO2 photonic crystal heterostructures for enhanced photocatalytic properties. Applied Catalysis B: Environmental, 168, 408-415(2015).

[46] Chang FENG, Xiaoyan DENG, Xiaoxiao NI et al. Fabrication of canbon modified porous ZnO nanorods with enhanced photocatalytic activity. Acta Physico-Chimica Sinica, 31, 2349-2357(2015).

[47] W SHI, F GUO, H WANG et al. Carbon dots decorated the exposing high-reactive (111) facets CoO octahedrons with enhanced photocatalytic activity and stability for tetracycline degradation under visible light irradiation. Applied Catalysis B: Environmental, 219, 36-44(2017).

[48] S MANCHALA, L R NAGAPPAGARI, S M VENKATAKRISHNAN et al. Facile synthesis of noble-metal free polygonal Zn2TiO4 nanostructures for highly efficient photocatalytic hydrogen evolution under solar light irradiation. International Journal of Hydrogen Energy, 43, 13145(2018).

[49] Y MATSUMOTO. Energy positions of oxide semiconductors and photocatalysis with iron complex oxides. Journal of Solid State Chemistry, 126, 227e34(1996).

[50] P ANDREA, B GIANCARLO, P MARIO et al. Photocatalytic degradation of azo dyes. Pilot plant investigation. Industrial & Engineering Chemistry Research, 53, 2566-2571(2014).

[51] S K KANSAL, M SINGH, D SUD. Studies on photodegradation of two commercial dyes in aqeous phase using differant photocatalysts. Journal of Hazardous Materials, 141, 581-590(2007).

[52] S VERMA, B T RAO, J JAYABALAN et al. Studies on growth of Au cube-ZnO core-shell nanoparticles for photocatalytic degradation of methylene blue and methyl orange dyes in aqueous media and in presence of different scavengers. Journal of Environmental Chemical Engineering, 7, 103209(2019).

[53] P K JASEELA, J GARVASIS, A JOSEPH. Selective adsorption of Methylene Blue (MB) dye from aqueous mixture of MB and Methyl Orange (MO) using Mesoporous Titania (TiO2)-Poly Vinyl Alcohol (PVA) nanocomposite. Journal of Molecular Liquids, 286, 110908(2019).