Pure ZnO Research Articles

Fabrication of piezotronic ZnO p-n homojunction via metal/oxygen defects modulation for efficient photoelectrocatalysis

Homojunction is a viable alternative strategy to realize excellent charge separation for enhancing photoelectrocatalytic performance. However, the feasible regulation of the homojunction interface remains challenging. Herein, a ZnO n-p homojunction with the piezotronic effect is constructed via an in-situ solvothermal method for enhancing photoelectrocatalytic activity. ZnO nanorods are transformed from n-type to p-type ZnO nanoparticles with zinc vacancies, leading to the n-p homojunction. The optimal NPZ-36 exhibits a superior photocurrent density of 1.56 mA/cm2 at 1.23 V vs. RHE and a high incident photon to current conversion efficiency of 75 % at 360 nm. Impressively, with the merits of inherent piezoelectric and photocatalytic properties of wurtzite ZnO, the piezoelectric-enhanced photoelectrochemical activity originates from the simultaneous promotion of bulk charge transfer and interfacial charge separation in ZnO n-p homojunction. The photocurrent density of NPZ-36–900 can reach to 2.02 mA/cm2 under the stirring rate of 900 rpm, which is 2.1 times higher than that of pure ZnO photoanode.

A novel MXene-bridged Z-scheme ZnO@Nb2CTx MXene@carbon nitride nanosheets photocatalyst for efficient enrofloxacin degradation

A Z-scheme photocatalyst, ZnO@Nb2CTx MXene@carbon nitride nanosheets (ZNC), is synthesized by the hydrothermal and electrostatic self-assembly strategy. The degradation test shows that ZNC photocatalyst has an enhanced photocatalytic efficiency of Enrofloxacin (ENR) degradation under visible light irradiation. The ENR removing rate has reached 98.2 % after 40 min light irradiation and has a degradation rate of 0.0961 min−1, which is 4.78 times higher than pure ZnO and 3.987 times higher than CNNS. Besides, a possible ENR degradation pathway was studied via LC-MS method. Furthermore, in-situ high resolution XPS spectroscopy and DFT calculation confirmed the direction of electron flow in the ZNC photocatalyst, highlighting that its improved degradation efficiency primarily stems from the introduction of the MXene electron transport layer, which promotes efficient charge transfer and separation of electron-hole pair. This study provides a guidance to design highly efficient Z-scheme photocatalyst for ENR degradation.

High-performance ethanol sensor based on self-assembled BaTiO3/ZnO composite hierarchical nanostructure

Excessive emission of volatile organic compounds (VOCs) has caused serious harm to the ecological environment and human survival. It is necessary to develop gas sensors with high response, outstanding selectivity, and low power consumption to provide basic protection for human health environment. In this work, BaTiO3 nanospheres are prepared by solution method, and BaTiO3/ZnO composites are further synthesized based on facile hydrothermal technique. The gas sensitive investigations show that the response of BaTiO3/ZnO composite sensor to 100 ppm ethanol is reach up to 94, and the optimal operating temperature is significantly reduced. The response time of BaTiO3/ZnO is reduced to 66 s, and full recovery can be achieved within 162 s. In general, the performance of BaTiO3/ZnO nanocomposite sensors is better than that of pure BaTiO3 nanospheres and ZnO nanosheets, which may be related to the unique morphology, improved surface properties of BaTiO3/ZnO composites and the n-n heterojunction effect. Finally, the gas-sensing mechanism of the as-prepared BaTiO3/ZnO semiconductor in air and ethanol is discussed in detail.

OPTICAL PROPERTIES AND ANTIBACTERIAL ACTIVITY OF Ni, Mg, AND Fe-DOPED ZnO

In recent years, research on pure ZnO, Ni-doped ZnO, Mg-doped ZnO, and Fe-doped ZnO nanostructures has been gradually progressing to create more effective materials that may be applied in a variety of applications. In this investigation, hydrothermal synthesis was used to create both pure ZnO nanoparticles and ZnO that had been doped with Ni, Mg, and Fe at a concentration of 7%. Before testing the nanostructures’ ability to inhibit harmful bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Enterobacter sp.), they were shown to have antibacterial activity. With the use of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and ultraviolet–visible (UV–Vis), their physicochemical characteristics were initially determined. When Ni, Mg, and Fe are inserted into ZnO, XRD measurements show that the particle size decreases from 28.94[Formula: see text]nm to 19.96[Formula: see text]nm. The optical bandgap decreases from 3.17[Formula: see text]eV to 3.08[Formula: see text]eV with the least value for Fe/ZnO NPs, according to UV–Vis spectral data, which also shows that the absorption edge changes to higher wavelengths (redshift). This research has produced nanoparticle samples of Ni/ZnO, Mg/ZnO, and Fe/ZnO that, when compared to the pure ZnO sample, show intriguing antibacterial activity.

Proliferating optoelectronic properties of doped ZnO nanoparticles

Ag-doped ZnO nanocomposites were synthesized precisely by adopting a wet chemical method to explore their optoelectronic characteristics for LED applications. Characterization studies have progressed for substantiation of its structural, and functional characteristics in conjugation with the optical properties of nanocomposites before and after doping. The metal-oxygen bonding was affirmed from IR spectra and excitation characteristics were detailed from UV–visible absorption spectra. The SEM images along with Energy dispersive X-ray analysis deliberates hexagonal morphology for pure ZnO which was surprisingly reformed into poly hexagon structures after doping with silver ions. The pertinence of the target material for LED application was verified by performing photoluminescence and charge density measurements. The doping of silver ions into ZnO presents a novel avenue in the field of optronics and serves as appropriate phosphors for light-emitting diodes. The application of the title compound was established by providing nano coating to LED bulb and emission efficiencies was recorded before and after coating. The present research recommends a unique method of nanocoating of LED bulb for efficient light intensity.

Synthesis, characterization, DFT calculations, and anticancer properties of VI-period and f-block elements-substituted zinc oxide nanopowders

Nanotechnology provides promising ways in which a wide range of new materials can be manufactured which appear to have enormous potential in the field of biomedicine and life sciences. ZnO can be applied in many physical and optical processes and used as a good anti-cancer agent. ZnO NPs are recognized as SAFE or GRAS, non-toxic and biocompatible particles. In this study, wurtzite ZnO samples co-doped by rare earth elements (Tb, Er) were prepared via sol-gel auto-combustion route and their crystallographic structure as well as their morphologies were examined using XRD and TEM techniques. The analysis disclosed that all synthesized products crystallized in a hexagonal structure and the crystallites/particles size diminished with the increase of co-doping content. The electronic structure and optical properties of the different products were assessed using DFT calculations. Doping Tb and Er rare earth elements into ZnO has a significant effect on its optoelectronic properties. The computational study showed that the co-doping of Tb and Er on pure ZnO decreased the band gap and increased the refractive index. The extinction spectrum of pristine ZnO showed a peak in the ultraviolet region at 5 eV, while those of the co-doped ZnO samples displayed stronger peaks in the infrared region (near 0.4 eV). The anticancer properties of Tb/Er co-doped ZnO nanoparticles were examined on cervical cancer (HeLa cells) and colon cancer (HCT-116) by using an in vitro MTT assay. The cell viability assay findings indicated a reduction in HeLa and HCT-116 cells after 48 h of treatment of the synthesized samples. The treatment with co-doped ZnO nanoparticles produced chromatin condensation and formation of apoptotic bodies in HCT-166 cells, which indicates that the prepared co-doped ZnO nanoparticles induced programmed cell death in HCT-116 cells. According to these results, it can be concluded that the prepared Tb/Er co-doped ZnO nanoparticles have promising applications in developing new optoelectronic devices and also in treating cervical and colon cancers.

Optimization of an innovative hybrid approach ZnO-Doped PVP nanofibers for electrical devices applications

The solid solution of pure ZnO nanoparticles and doped Polyvinylepyrrolidone (PVP) green hybrid nanomaterial’s synthesized by using the electro spinning method. The synthetic polymer matrix nonwoven fibrous mats containing innovative properties are shown to shrink and encapsulated the zinc oxide materials to change the surface morphology when the concentration of PVP is increased from 1 % to 2 % dopants. The crystalline nature and morphological studies were examined by using x-ray diffraction and a scanning electron microscope. The average crystallite sizes of easily formed ZnO nanoparticles and nanorods that are 21 nm and 62 nm respectively. Moreover, the electrical and optical properties of the fibrous mesh were determined by using electrical impedance analyzer. The electrical conductivity values were measured in the pure ZnO nanoparticles in contrast to the doped ZnO/PVP. The tangent loss, dielectric constant, capacitance and relaxation time values are revealed in this study. All the characterization has been carried out at room temperature. The relaxation time for 1 %, and 2 % ZnO/PVP is (0.8 ns) and (0.79 ns) respectively which is suitable for the application of trigger using devices. The overall findings of this study implemented in a wide range of technologies i.e. photonics, electronics and super capacitor devices etc.

Characterization of GO Added ZnO Crystal Growth Using Electric Current Heating Method

ZnO has attractive and great properties especially in the fields of photonics, electronics and optics and it is widely used in the manufacturing industry of photodetectors, laser diodes and gas detectors. Therefore, various methods have been carried out to produce ZnO crystals and one of them is the Electric Current Heating method. Electric Current Heating (ECH) method is a fabrication technique applied in researches to grow ZnO crystal on a ceramic bar. This method is preferred because of it is easy to operate in laboratory, low growth temperature and also low cost. In this research, by using powder metallurgy process, Graphene Oxide/GO (in various weight percentage) added into ZnO was pelletized in a compaction die with dimension of 14.95 mm x 30 mm x 40 mm and pressure of 4 bar. The pellet green body was then sintered at 1100 °C with rate 10.0 °C/min for 3 hours. The sintered GO added ZnO ceramic was cut into ceramic bar with dimensio of 13mm x 2mm x 2mm. ECH with current 3 A and applied voltage of 30 V was used to heat the ceramic bar to produce crystals. Under scanning electron observation, it was found different crystal-like structures for each percentage GO addition. UV-Vis measurement has shown that each crystal-like structure of a GO added ZnO has own degree of energy absorbsion because of different band gap. Addition GO into ZnO would increase band gap of pure ZnO.

Sol-Gel technique, characterization and photocatalytic degradation activity of Manganese doped ZnO nanoparticles

Photocatalysis using semiconductor metal oxide stands out as a highly effective and efficient method for eliminating organic pollutants from wastewater. This study aims to assess the photocatalytic capabilities of Mn doped ZnO nanocomposites in degrading methylene blue (MB) dye under ultra-violet light exposure. This study details the synthesis of ZnO photocatalysts through a straightforward one-step sol-gel method, incorporating varying levels of Mn-doping (0%, 2% & 4%). The structural and optical attributes were examined using techniques such as powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and UV-Vis diffuse reflectance spectra. X-ray diffraction analyses verified the presence of a hexagonal wurtzite crystal structure in all synthesized samples, exhibiting a high degree of crystallinity. In addition, an investigation into the impact of Mn impurities on the photocatalytic performance of ZnO catalysts was conducted in the context of methylene blue (MB) degradation. The experimental findings revealed that the Mn doped ZnO nanoparticles produced exhibited significantly superior photocatalytic performance compared to pure ZnO when used in breaking down methylene blue under UV-light exposure. This study proposes that these Mn doped ZnO could serve as a highly effective photocatalyst for treating water contaminated with certain chemically persistent synthetic organic dyes. The improved photocatalytic capabilities of ZnO nanostructures doped with Mn were ascribed to the synergistic impact of increased surface area in ZnO nanosphere and enhanced efficiency in charge separation resulting from optimized Mn doping. A potential explanation for the heightened photocatalytic performance of Mn-doped ZnO nanostructures is proposed tentatively.

Characterization of Pure and Doped ZnO Nanostructured Powders elaborated in Solar Reactor

The synthesis of nano-oxides is an important field of nanotechnology, as these materials possess unique properties and applications. Several methods have been developed for synthesizing nano-oxides, each offering advantages and disadvantages depending on the desired material characteristics. Solar energy focused on solar reactors can be utilized for nano-oxide elaboration, offering a sustainable and environmentally friendly approach. The current article presents the research carried out for the elaboration of pure and doped nanostructured zinc oxides using solar energy. The morphostructural characteristics were determined by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and the Brunauer-Emmett-Teller method. The attenuated total reflectance Fourier transform infrared spectroscopy confirmed the synthesis of pure and doped nanostructured ZnO. The optical properties were highlighted by UV-VIS Spectroscopy. The research points out that crystallite sizes vary between 37 and 51 nm due to the influence of doping metal. The morphology associated with these particles is predominantly whiskers with elongated parts between 0.18 and 1.4 um. Doping with Fe, Si, Yb, and Ce causes a wider band gap compared to pure ZnO nanoparticles. As solar energy becomes more accessible and efficient, solar-driven synthesis of pure and doped ZnO is poised to be a crucial factor in shaping the future of material science and technology.

Synthesis and characterization of bi-functional Cu and Ni co-doped ZnO photocatalysts for organic pollutant degradation and antimicrobial activity

The study of visible light active photocatalysts for organic pollutants degradation and antimicrobial activity has gained significant attention in recent years. Herein, we report the synthesis of pure ZnO, Ni-doped ZnO (Ni-ZnO), Cu-doped ZnO (Cu-ZnO), and Cu and Ni co-doped ZnO (CuNi-ZnO) photocatalysts via a facile coprecipitation method. These photocatalyst materials were characterized using various analytical techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscope (HR-TEM), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–Vis), photoluminescence (PL), and total organic carbon (TOC) analysis. XRD patterns confirm the presence of a mixed phase in the CuNi-ZnO sample. The presence of Cu, Ni, and Zn in CuNi-ZnO was verified through the XPS spectra. The nanoparticle-like morphology of the CuNi-ZnO photocatalyst was confirmed using HRTEM analysis. The FTIR spectra reveal the chemical bonds present in the materials. UV–visible spectroscopy was employed to determine the band gap of the materials, revealing a value of 3.10 eV for CuNi-ZnO. The mitigation in recombination of excited electrons (e−) and holes (h+) in CuNi-ZnO is validated through photoluminescence (PL) studies. The synthesized materials were used for the degradation of Indigo carmine (IC) dye and antimicrobial activity. The results showed that the optimized CuNi-ZnO sample displayed a better visible light photocatalytic performance (93.32 % IC dye degradation efficiency in 60 min) than the other samples. A notable degree of mineralization was observed with a reduction in total organic carbon (TOC) reaching 65.91 %. Additionally, the photocatalyst showed antimicrobial activity against both S. aureus and E. coli. Furthermore, a plausible visible light photocatalytic mechanism was proposed for the degradation of IC dye using the CuNi-ZnO photocatalyst.

Heterostructure interfaces and dimensionally transformed GaO/ZnO nanostructures for room-temperature hydrogen gas sensors

This work demonstrates the significant prospective of GaO/ZnO hybrid nanostructures for high-performance hydrogen gas sensing. The wavy grains of GaO support the structural transformation of ZnO nanorod into nanosheets by providing appropriate nucleation sites for ZnO growth. Compared to pure ZnO and GaO, GaO/ZnO exhibited a sixfold increase in H2 response (60% at 500 ppm), excellent selectivity towards H2 among other interfering gases, and outstanding long-term stability (retaining 98% of its initial response after 36 days). This greater performance rises from the unique morphology and different surface interactions within the GaO/ZnO hybrid nanostructure, assisting multiple adsorption sites and various hydrogen interaction pathways. Alloying effects, internal strain, and the presence of both GaO and ZnO regions within the nanosheets further contribute to enhanced sensitivity, selectivity, and stability.

CuO-ZnO nanocomposite for photocatalytic application

The rising levels of water pollution and climate change contribute to water shortages. These factors influence the loss of the environment’s biodiversity and threaten human health. Toxic dye pigments from industries are a significant source of pollution. In this article, we present the synthesis method, characteristics, and photocatalytic properties of the CuO-ZnO nanocomposite, which may affect the degree of decomposition of dyes found in water. The nanocomposite consisting of copper oxide nanowires with zinc oxide nanostructures (CuO-ZnO nanocomposite) was prepared by physical vapor deposition and thermal oxidation methods. The crystalline structure, surface topographies and morphologies, elemental composition, and optical properties of the obtained samples were studied with various techniques such as x-ray diffraction analysis, high-resolution transmission electron microscopy, field emission scanning electron microscopy, energy dispersive x-ray analysis, and UV-vis spectroscopy. The photocatalytic activity of the nanocomposite was measured by testing the degradation of methylene blue under visible irradiation. An increase in the photocatalytic activity of the nanocomposite was observed compared to pure CuO and ZnO. The CuO-ZnO nanocomposite demonstrated a high dye degradation of about 94% during 120 min.

Influence of sintering temperature on structural and optical properties of pure and Cl-doped ZnO nanoparticles

In this study, we conducted a detailed analysis of the sintering process of both pristine and 25 mg/g Cl-doped ZnO nanoparticles at varying temperatures to determine the optimum sintering temperature. Our findings revealed an optimal sintering temperature of 600 °C, resulting in higher phase purity (only hexagonal ZnO phase), smaller particle sizes of about 88–92 nm, and higher emission intensity for both pristine and Cl-doped ZnO nanoparticles. The band gap reduces from 3.63 eV to 3.20 for pristine and 3.63 eV to 3.10 for Cl-doped ZnO nanoparticles by increasing the sintering temperature from 200 °C to 1000 °C. The introduction of Cl in the ZnO lattice introduced a new defect level, having a broadband excitation band peaking at 374 nm. The luminescence of ZnO peaked at approximately 503 nm, which can be attributed to the transition from oxygen vacancies in the ZnO lattice. Notably, the emission intensity of the Cl-doped samples sintered at 600 °C was found to be 6.5 times higher than that of the pristine ones. Moreover, we found that the luminosity of ZnO:Cl nanoparticles was around 68% that of ZnS:Ag nanoparticles, which are typically used for radon detection and have similar efficiency to standard Lucas cells. Our preliminary findings suggest that Cl-doped ZnO nanoparticles sintered at 600 °C for 5 h could effectively develop radiation detectors, particularly for radon monitoring and related applications.

3D porous ZnO microspheres sensitized by Ag quantum dots for highly responsive TEA sensors

The study aims to create a highly responsive gas sensor for TEA. In order to achieve this goal, spherical ZnO with layered structure was synthesized by a simple hydrothermal method. Subsequently, Ag quantum dots (QDs) are precipitated onto the surface of the ZnO microspheres. The ZnO microspheres were analyzed to demonstrate that they are comprised of porous nanosheets measuring roughly 10 μm in diameter. The composite with the optimal mass percentage displayed outstanding sensitivity to triethylamine (TEA), yielding a response of 1223, approximately 90 times higher than that of the pure ZnO sensor. Furthermore, this composite also demonstrated remarkable selectivity towards TEA. The exceptional detection results were achieved due to the catalytic influence of Ag as a precious metal, coupled with the distinctive structure of quantum dots and ZnO materials.

Enhanced ozone gas detection with Sb doped ZnO nanorods synthesized on MEMS microheater

Metal oxide semiconductors infused with noble metals or metalloids are studied and employed in semiconductor sensors applications to a greater extent. In this study, antimony (Sb) is doped with ZnO in 4 different concentrations to compare the optimal parameters in gas sensing properties. Sb/ZnO nanostructure is synthesized by hydrothermal process and deposited on MEMS (Micro electro mechanical system) microheater device. The morphology of the nanostructure is analyzed for planar structure, oxidation states and the presence of Sb/ZnO is successfully verified. Ozone is a powerful oxidizing gas which is a health hazard in public places, so low concentrations of ozone is tested with Sb/ZnO sensor at various parameters. Since Sb acts as catalyst to promote the gas sensing properties, the sensor responses have been enhanced compared to pure ZnO sensor. Sensor performed its best at 200 °C and has the lowest detection gas concentration of 10 ppb. Sb/ZnO showed good selectivity over ozone gas.

Influence of Mg concentration in Zn1-xMgxO buffer layers for enhanced Cu2(Sn,Ge)S3 solar cells performance

This study is focused on the influence of band alignment at the buffer/absorber interface of Cu2(Sn,Ge)S3 (CTGS) thin film solar cells fabricated on soda-lime glass substrates with an Al/Ni/Zn0.92Mg0.08O:Al/Zn1-xMgxO − 2nd buffer/CdS − 1st buffer/CTGS/Mo/glass structure. Here, Zn1-xMgxO 2nd buffers are used to minimize the energy losses and prevent direct contact between the Zn0.92Mg0.08O:Al and CTGS absorber. The study found that the conduction band offset between Zn1-xMgxO and CTGS changed from −0.68 eV (i.e., cliff-like, negative band offset) to +0.60 eV (i.e., spike-like, positive band offset) as the Mg content x increased in Zn1-xMgxO from 0 (i.e., pure ZnO) to 0.52. Optimization of the conduction band offset via tuning the Mg content in Zn1-xMgxO 2nd buffer reduced carrier recombination in the CTGS devices, improving band bending and enhancing the power conversion efficiency up to 3.1%. This was primarily attributed to an increase in short-circuit current density and fill factor.

Visible-light-driven 2D π-conjugated polyimide/ZnO efficiently removes tetracycline

Heterojunction organic-inorganic composites are promising for wastewater treatment due to their excellent physical and chemical properties. ZnO was immobilized on the PI surface using the hydrothermal technique to prepare PI/ZnO n-n heterojunctions with outstanding visible photocatalytic properties. The photocatalytic performance of different ratios of PI/ZnO composites was significantly improved in comparison to pure PI and ZnO, among which 40% PI/ZnO showed the most outstanding results. The 40% PI/ZnO can adsorption remove around 40% of tetracycline (TC) in 20 min in entirely shaded conditions and can attain up to 90% of the TC removal efficiency in 40 min under visible light exposure. The formation of a PI/ZnO heterojunction enhances the efficiency of charge separation and reduces the recombination of photogenerated electron-hole pairs, resulting in improved photocatalytic performance. Meanwhile, the 40% PI/ZnO composites showed a substantial increase in specific surface area (205.22 m2/g) compared to pure PI and ZnO, which was 103 and 25 times that of PI and ZnO, respectively. The increase in surface area provided a larger number of adsorption sites, thereby increasing the contact area between the pollutants and the photocatalysts, which led to a significant improvement of the PI/ZnO composites in the adsorption and photocatalytic properties. In this study, the heterojunction was formed by the composite of conjugated polymer and metal oxide, so that the composites could remove the organic matter more efficiently by adsorption and then photocatalysis, which will provide some ideas for the development of more efficient conjugated polymer materials.

Fabrication and characterization of solar active BN coupled with ZnO composite catalysts for efficient photocatalytic detoxification of methyl orange dye under solar and visible light irradiation

In this paper, pure ZnO and hexagonal boron nitride (BN) loaded ZnO nanorods were synthesized via a simple hydrothermal method. XRD analysis revealed good crystallinity and hexagonal wurtzite structure of the synthesized materials. FE-SEM images showed the nanorod-like structure of the ZnO material. The UV-DRS spectra showed a decrease in the optical bandgap of BN-ZnO due to the loading of BN. The outcomes from the EIS analysis indicated that the 3% BN-ZnO photocatalyst exhibited the most favorable recombination rate for electron-hole pairs and the least resistance to electron transfer. Photocatalytic evaluation for methyl orange (MO) detoxification under sunlight and visible light illumination revealed that 3% BN-ZnO showed the highest activity, and kinetic studies showed pseudo-first-order degradation. Moreover, the sunlight process outperforms than visible light process, which can be attributed to the ≈ 4% UV radiation available in the solar spectrum. TOC studies confirmed the mineralization of the MO dye. Trapping experiments using various quenchers show that superoxide radicals (O2•−) anion play a major role in the degradation process. Finally, we proposed a plausible photocatalytic mechanism based on our findings.

CaFe2O4/Ag/ZnO z-scheme heterojunction material for photocatalytic decomposition of ciprofloxacin

The Z-type heterojunction CaFe2O4/Ag/ZnO composite photocatalyst was successfully synthesized by the microwave-assisted hydrothermal methods. The photocatalytic activity of the CaFe2O4/Ag/ZnO was evaluated by the degradation of ciprofloxacin (CIP). The characterization results indicated that Ag doping can decrease the band gap (Eg) of ZnO and enhance its visible light absorption capacity. Ag/ZnO forms a Z-type heterojunction with CaFe2O4, which can significantly promote effective photogenerated carrier separation and enhance the visible light catalytic activity of the CaFe2O4/Ag/ZnO composite catalyst. It was observed that the degradation effect of the CaFe2O4/Ag/ZnO on CIP was significantly better than pure ZnO and CaFe2O4.