Efficient Heterojunction Photocatalysts Research Articles

Interfacial engineering of Ti3C2 MXene/CdIn2S4 Schottky heterojunctions for boosting visible-light H2 evolution and Cr(VI) reduction

Developing efficient heterojunction photocatalysts that have a high charge carrier separation rate and improved light-harvesting capacity is a crucial step in solving energy crisis and reducing environmental pollution. Herein, we synthesized few-layered Ti3C2 MXene sheets (MXs) by a manual shaking process, and combined with CdIn2S4 (CIS) to construct novel Ti3C2 MXene/CdIn2S4 (MXCIS) Schottky heterojunction through a solvothermal method. The strong interface between two-dimensional (2D) Ti3C2 MXene and 2D CIS nanoplates led to enhanced light-harvesting capacity and promoted charge separation rate. Additionally, the presence of S vacancies on the MXCIS surface helped to trap free electrons. The optimal sample, 5-MXCIS (with 5 wt% MXs loading), exhibited outstanding performance for photocatalytic hydrogen (H2) evolution and Cr(VI) reduction under visible light due to the synergistic effect of enhanced light-harvesting capacity and charge separation rate. The charge transfer kinetics was thoroughly studied using multiple techniques. The reactive species of •O2−, •OH and h+ were generated in 5-MXCIS system, and e− and •O2− radicals were found to be the main contributors to Cr(VI) photoreduction. Based on the characterization results, a possible photocatalytic mechanism for H2 evolution and Cr(VI) reduction was proposed. On the whole, this work provides new insights into the design of 2D/2D MXene-based Schottky heterojunction photocatalysts for boosting photocatalytic efficiency.

Construction of hierarchical core-shell Z-scheme heterojunction FeVO4@ZnIn2S4 for boosted photocatalytic degradation of tetracycline

Constructing core-shell heterojunction and designing hierarchical structures have been considered as efficient strategies for enhancing the activity and stability of photocatalysts. Herein, a novel hierarchical core-shell Z-scheme heterojunction FeOV4@ZnIn2S4 was prepared via the in-situ growth of ZnIn2S4 on the surface of FeVO4 submicron bar with a facile solvothermal method. The formation of the hierarchical core-shell heterostructure between FeVO4 and ZnIn2S4 improved light-harvesting ability and promoted the separation of photoinduced electron-hole pairs. The prepared FeOV4@ZnIn2S4 exhibited superior photocatalytic activity toward tetracycline. The removal efficiency of tetracycline reached up to 90.8% within 120 min. The degradation rate were 5.75 and 2.06 times that of FeVO4 and ZnIn2S4, respectively. Furthermore, Z-Scheme charge transfer mechanism at the interface between FeVO4 and ZnIn2S4 was proposed based on the results obtained from radical trapping test and electron spin resonance (ESR), which revealed that •O2−, •OH and h+ all act as active species in photocatalytic reaction. This work can bring a strategy for the preparing highly efficient heterojunction photocatalysts.

Enhanced interfacial charge transfer and photothermal effect via in-situ construction of atom co-sharing Bi plasmonic/Bi4O5Br2 nanosheet heterojunction towards improved full-spectrum photocatalysis

Constructing a plasmonic heterojunction photocatalyst is a prospective approach to improve full-spectrum photocatalytic performance. However, low interfacial charge transfer efficiency due to lattice mismatch severely limits its photocatalytic performance. Herein, a Bi atom co-sharing Bi/Bi4O5Br2 plasmonic heterojunctions were fabricated via in-situ reduction. Experimental characterizations and theoretical calculations demonstrate that the co-sharing Bi atom enables intimate contact in the heterointerface, significantly promoting interfacial charge transfer and separation. In addition, Bi metal's surface plasmon resonance effect extends the photoresponse to the near-infrared region and enhances the photothermal performances, significantly improving solar energy's utilization efficiency. By these prominent features, the optimized Bi/Bi4O5Br2 heterojunctions show that the photocatalytic degradation ratio of BPA reaches 100 % within 40 min under full-spectrum irradiation, which is about three times higher than that of Bi4O5Br2. Moreover, the photocatalytic efficiency was significantly increased by 7.5 times with the increase in temperature under NIR light irradiation due to the photothermal effect. This work offers new insights into the rational design of low-cost, highly efficient, and stable Bi-based plasmonic heterojunction photocatalysts for full solar spectrum utilization by integrating plasmonic nanostructures and photothermal effect.

Guest Editorial: Solar Energy Utilization

Guest Editorial: Solar Energy Utilization

SnO2 and CuO anchored on zeolite as an efficient heterojunction photocatalyst for sunlight-assisted degradation of cefixime.

The fabrication of heterojunction nanocomposites has been proven as a highly efficient strategy to achieve promising photocatalysts. In this study, tin oxide (SnO2) and copper oxide (CuO) nanoparticles (NPs) were synthesized in situ using Rosmarinus officinalis and simultaneously anchored on zeolite for the fabrication of zeolite/SnO2/CuO as a novel heterojunction photocatalyst. The performance of zeolite/SnO2/CuO was assessed against photodegradation of cefixime as a model pharmaceutical contaminant. A good catalytic potential and synergistic effect was obtained for zeolite/SnO2/CuO compared to pure SnO2 and CuO NPs. Under optimum conditions, 89.65% of cefixime was degraded after 2.5 h under natural sunlight. Based on radical quenching experiments, the importance of involved oxidizing species in the photodegradation of cefixime using zeolite/SnO2/CuO was in order of h+ > •OH > [Formula: see text]. Among studied anions, the highest inhibitory effect was observed for nitrate ion. Also, the main intermediates of the photodegradation process of cefixime in zeolite/SnO2/CuO system were determined by HPLC-MS and the possible pathways were suggested. More than 83% cefixime was removed after three catalyst reuse cycles, indicating a cost-effectiveness potential in the reusability of zeolite/SnO2/CuO. Also, the toxicity and plant growth tests revealed the feasibility of discharging the treated cefixime solutions to irrigate agricultural crops. Overall, the obtained results provide a promising technique with a synergistic feature for the efficient removal of organic pollutants.

An efficient and multifunctional S-scheme heterojunction photocatalyst constructed by tungsten oxide and graphitic carbon nitride: Design and mechanism study

The design of multifunctional photocatalyst with strong redox performance is the key to achieve sustainable utilization of solar energy. In this study, an elegant S-scheme heterojunction photocatalyst was constructed between metal-free graphitic carbon nitride (g-C3N4) and noble-metal-free tungsten oxide (W18O49). As-established S-scheme heterojunction photocatalyst enabled multifunctional photocatalysis behavior, including hydrogen production, degradation (Rhodamine B) and bactericidal (Escherichia coli) properties, which represented extraordinary sustainability. Finite-difference time-domain (FDTD) simulations manifested that the integration of double-layer hollow g-C3N4 nanotubes with W18O49 nanowires could expand the light harvesting ability. Demonstrated by density functional theory (DFT) calculations and electron spin resonance (ESR) measurements, the S-scheme heterojunction not only promoted the separation of carriers, but also improved the redox ability of the catalyst. This work provides a theoretical basis for enhancing the photocatalytic performances and broadening the application field of photocatalysis.

Cu2(OH)2CO3 clusters modified MoS2@Ag2S heterojunctions for efficient photocatalytic pollutant degradation and hydrogen evolution

• Cu 2 (OH) 2 CO 3 clusters modified MoS 2 /Ag 2 S heterojunctions were constructed firstly. • Efficient methyl orange photodegradation and hydrogen evolution activity was achieved. • Reaction mechanism regarding to the high activity was proposed. In this report, Cu 2 (OH) 2 CO 3 -MoS 2 @Ag 2 S composites were constructed by combining with ions exchange reaction and precipitation method. The results showed that the MoS 2 microflowers were coated by the Ag 2 S nanoparticles. The as-prepared Cu 2 (OH) 2 CO 3 -MoS 2 @Ag 2 S composites exhibited the highest rate constant for Methyl Orange(MO) degradation (14.17x10 -3 min -1 ) and H 2 evolution (1.488mmol/g/h) under visible light irradiation, respectively, which is 20.5 and 4.7 times higher than that of MoS 2 . The enhanced MO degradation and H 2 evolution performance of Cu 2 (OH) 2 CO 3 -MoS 2 @Ag 2 S system is attributed to: 1) The intimate contact between Ag 2 S and MoS 2 is beneficial to charge transfer; 2) Efficient solar light harvesting of Ag 2 S on the surface of MoS 2 microflowers; 3) Cu 2 (OH) 2 CO 3 clusters served as photogenerated electrons traps further promote the separation of photogenerated charge carriers. The results of trapping experiment revealed that e - and h + acted as key roles in the process of photocatalytic MO degradation and water splitting. Our research provides great potential in constructing highly efficient heterojunction photocatalysts in environment and energy issues.

Efficient Visible-Light Driven Photocatalytic Hydrogen Production by Z-Scheme ZnWO4/Mn0.5Cd0.5S Nanocomposite without Precious Metal Cocatalyst

How to restrain the recombination of photogenerated electrons and holes is still very important for photocatalytic hydrogen production. Herein, Z-scheme ZnWO4/Mn0.5Cd0.5S (ZWMCS) nanocomposites are prepared and are applied as visible-light driven precious metal cocatalyst free photocatalyst for hydrogen generation. The ZnWO4/Mn0.5Cd0.5S nanocomposites with 30 wt% ZnWO4 (ZWMCS-2) can reach a photocatalytic hydrogen evolution rate of 3.36 mmol g−1 h−1, which is much higher than that of single ZnWO4 (trace) and Mn0.5Cd0.5S (1.96 mmol g−1 h−1). Cycling test reveals that the ZMWCS-2 nanocomposite can maintain stable photocatalytic hydrogen evolution for seven cycles (21 h). The type of heterojunction in the ZWMCS-2 nanocomposite can be identified as Z-scheme heterojunction. The Z-scheme heterojunction can effectively separate the electrons and holes, so that the hydrogen generation activity and stability of the ZWMCS-2 nanocomposite can be enhanced. This work provides a highly efficient and stable Z-scheme heterojunction photocatalyst for hydrogen generation.

Rationally designed Ta3N5/ZnO Core-shell nanofibers for significantly boosts photocatalytic hydrogen production

The rational design of novel and efficient heterojunction photocatalysts is recognized as one of the significant challenges for achieving highly efficient solar-to-chemical energy conversion. Herein, we report a novel Ta3N5/ZnO core–shell nanofibers heterojunction photocatalyst for boosting photocatalytic H2 evolution activity through the combining of electrospinning and ALD process. Based on the combined strategies of nanostructure engineering and heterojunction, the enhanced photocatalytic activity of Ta3N5/ZnO hybrid sample is attributed to the synergistic effects of increased reaction sites and improved charge transfer. The optimized Ta3N5/ZnO-150 core–shell nanofibers heterojunction photocatalyst exhibited the highest photocatalytic hydrogen production activity of 1193.75 μmol g−1 h−1, which is about 7 times higher than the bare Ta3N5 nanofibers, and also superior to the most of Ta3N5-based photocatalysts ever reported.

Confinement effects of carbonized polymer dots and directional migration of ZnIn2S4 photogenerated charge carriers for enhanced water purification

Efficient heterojunction photocatalysts with spatial separation of photogenerated carriers are crucial to photocatalysis. Herein, the unique carbonized polymer dots/ZnIn2S4 (CPDs/ZIS) Z-scheme heterojunction is designed to realize efficient spatial directional separation of photogenerated carriers. The CPDs broaden the light absorption range of ZIS and lengthen the lifetime of photogenerated charges. As the enrichment center of photogenerated electrons and active site of activated oxygen, CPDs generate more superoxide radicals to facilitate mineralization of organic pollutants by means of confined catalysis. The Z-scheme migration mechanism of photogenerated carriers in the CPDs/ZIS composite preserves the original valence band potential of ZIS and retains more holes for oxidation. Compared to the pristine ZIS, the CPDs/ZIS composite delivers enhanced photocatalytic performance in pollutant degradation. Electron spin resonance spectroscopy, free radical capture experiments, and liquid chromatography/mass spectrometry are performed to elucidate the photocatalytic mechanism of CPDs/ZIS.

A compact Z-scheme heterojunction of BiOCl/Bi2WO6 for efficiently photocatalytic degradation of gaseous toluene

Construction of Z-scheme heterojunction photocatalysts with efficient electron-hole pairs separation and robust oxidation abilities is a promising strategy to decompose volatile organic compounds (VOCs). Herein, UV-light-driven BiOCl and visible-light-driven Bi2WO6 were successfully combined via a one-pot hydrothermal method and compact Z-scheme heterojunction photocatalyst BiOCl/Bi2WO6 was obtained. Owing to the similar precursors and synthesis conditions, the integrated BiOCl/Bi2WO6 heterojunction was intimate and homogenous, which resulted in the efficient separation of photogenerated carriers, and generated abundant holes (h+), hydroxyl radicals (·OH) and superoxide radicals (·O2–). The optimal BiOCl/Bi2WO6 photocatalyst (BWOCl-2), achieved by tailoring the amount of hydrochloric acid, exhibited almost 100 % of toluene degradation and excellent durability. Electron spin resonance (ESR) results revealed that h+, ·O2– and ·OH were dominant active species in the BiOCl/Bi2WO6 photocatalytic system. The degradation intermediate products were monitored by in situ Diffuse Reflection Infrared Fourier Transform spectroscopy (DRIFTS) and the possible photocatalytic mechanism was also revealed according to the band structure of BiOCl/Bi2WO6 heterojunction. This work provided a novel avenue to design an efficient homogenous heterojunction photocatalyst for the efficient degradation of VOCs under sunlight.

Chemical bonding interface in Bi2Sn2O7/BiOBr S-scheme heterojunction triggering efficient N2 photofixation

Rapid recombination of interfacial charges is considered to be the main obstacle limiting N2 photofixation. It is urgent but challenging to develop a precise and stable strategy to steer charge transfer. Herein, oxygen-vacancy-rich Bi2Sn2O7 (BSO) are designed to be mounted on ultrathin BiOBr (BOB) with Bi-O vacancy pairs to construct the chemical bonding interface. The Bi and O atoms exposed by defects form the new Bi-O bonds to strengthen the built-in electric field, thus constructing the Bi2Sn2O7/BiOBr (BSOB) S-scheme heterojunction. During irradiation, electrons in CB of BOB rapidly recombine with holes in VB of BSO, and the electrons enriched in CB of BSO endow the strong reduction power for BSOB to trigger efficient photocatalytic nitrogen reduction. The ammonia yield of BSOB can reach 459.04 μmol g−1 h−1 in pure water. This work provides atomic-scale insights for the construction of efficient S-scheme heterojunction photocatalyst based on chemical bonding interface.

Ce3+ self-doping CeO2-x@CuO nanowires arrays on copper mesh at the gas-liquid interface: Enhanced performance of reducing CO2 to methanol under visible light

S-scheme heterojunction can accelerate the separation of photogenerated electron-hole pairs and retain strong redox ability, so it has outstanding advantages and application prospects in the field of photocatalysis. The Ce3+ self-doping CeO2-x@CuO nanowires arrays on copper mesh were synthesized with the strategy of surface hydrogenation and hydrothermal calcination method. The morphology, composition and properties of the catalysts were determined by SEM, TEM, EDS, UV-VIS, PL, CO2-TPD and other characterization methods. Ce3+ self-doping introduces O vacancies on the surface of CeO2 without introducing heteroatoms. The O vacancies of CeO2-x could enhance the adsorption, activation and reduction of CO2. The existence of coaxial S-scheme heterojunctions could effectively enhance the light absorption range and the separation of photo-generated charges. The photocatalytic activity of the composite catalyst was much higher than that of pure CuO/copper mesh (CM) and CeO2, and the difference in activity of catalysts composed of different proportions was studied. When the Ce3+ self-doping CeO2-x loading was moderate, the methanol yield reached 6.73 μmol·gcat−1 after 4 h reaction under visible light, which is 5.26 times of CuO/CM and 9.35 times of CeO2. The reduction mechanism of the composite catalyst at the gas-liquid interface was studied. This work demonstrates a feasible strategy to create efficient S-scheme heterojunction photocatalysts with rich active surface O vacancies for photocatalytic CO2 reduction.

Rationally designed Ta3N5/BiOCl S-scheme heterojunction with oxygen vacancies for elimination of tetracycline antibiotic and Cr(VI): Performance, toxicity evaluation and mechanism insight

S-scheme heterojunction photocatalysts have been the “stars” in the field of photocatalysis. Herein, a novel S-scheme heterojunction of Ta3N5/BiOCl with oxygen vacancies (OVs) was fabricated via a facile method. The charge separation and transport mechanism of this Ta3N5/BiOCl S-scheme heterojunction was verified by the analyses of band energy structures, active species, photoelectric behaviors and DFT theoretical calculation. Compared with Ta3N5 and BiOCl, the Ta3N5/BiOCl unveils substantially upgraded photocatalytic property under visible light, and the photocatalytic efficiency for removal of tetracycline (TC) and hexavalent chromium (Cr(VI)) reaches 89.6% and 91.6%, respectively. The substantial enhancement of the photocatalytic activity is attributed to the synergistic effect of the S-scheme hetero-structure and oxygen vacancies, which improves the visible-light absorption, while promoting the spatial separation of charge carriers with the optimum redox capacity, thereby boosting the production of active species for catalytic reactions. The TC degradation pathway is deduced and the toxicity evolution of TC is appraised using the QSAR method. In a nutshell, this work gives a deep understanding of the photocatalytic mechanism based on Ta3N5/BiOCl as well as presents a newfangled thought for developing highly efficient S-scheme heterojunction photocatalysts for water decontamination.

A magnetically separable α-NiMoO4/ZnFe2O4/coffee biochar heterojunction photocatalyst for efficient ketoprofen degradation

In this study, a novel heterostructure i.e., ZnFe2O4 nanosphere-decorated α-NiMoO4 nanorods on coffee biochar (BC), was fabricated via a hydrothermal method. The magnetically separable α-NiMoO4/ZnFe2O4/BC composite demonstrated 98.65 % degradation of ketoprofen (KP) in 180 min under visible light irradiation. Analysis of cyclic tests, total organic carbon, and fluorescence excitation-emission matrices revealed the excellent stability and mineralization abilities of photocatalysts, respectively. The effects of influencing factors (pH, anions, and different concentrations of KP/photocatalysts) on degradation of KP by the photocatalysts were suggested as promising prospects in water/wastewater treatment. BC acts as a conductor and an electron mediator in heterostructure. The enhanced photocatalytic performance of the heterostructure was ascribed to increased visible light absorption and efficient photoinduced charge carrier separation. Furthermore, photoluminescence spectral and electrochemical investigations indicated the efficient separation of photoinduced charge carriers. Electron spin resonance spectroscopy and scavenger experiments demonstrated that •OH played a major role in KP degradation. According to the liquid chromatography-tandem mass spectroscopy analysis, KP was degraded via three degradation pathways by 24 degraded intermediates. This study provides a new perspective on fabrication of efficient heterojunction photocatalysts exhibiting good recovery and insight on mechanisms and pathways underlying KP degradation.

Construction of Zn0.2Cd0.8S/g-C3N4 nanosheet array heterojunctions toward enhanced photocatalytic reduction of CO2 in visible light

The efficiency of photocatalytic CO2 reduction is severely limited by slow surface reaction kinetics and poor structural stability. In this study, a three-dimensional Zn0.2Cd0.8S/g-C3N4 (ZnCdS/CN) nanosheet array with type Ⅱ-scheme heterojunction structures was prepared using a mild in situ method. This heterojunction structure exhibited greatly improved carrier separation and specific surface area (45 m2 g−1), excellent stability, and broad-spectrum visible-light sensitivity. Without the use of any sacrificial agent, ZnCdS/CN20% demonstrated the highest photocatalytic efficiency of all the samples, with a CH3OH yield of 700.5 μmol·g−1·h−1. The type-Ⅱ-scheme heterojunction structure was responsible for the remarkable activity and stability because the photogenerated holes were transmitted to g-C3N4 across the heterojunction interface for the oxidation reaction, while the photogenerated electrons accumulated on Zn0.2Cd0.8S for the reduction reaction. This structure prevented oxidative corrosion on Zn0.2Cd0.8S and significantly improved the photogenerated electron–hole separation. This synthetic strategy provides new perspectives on the design and construction of efficient heterojunction photocatalysts for the solar-driven catalytic conversion of CO2.

Flower-like microspheres Z-scheme Bi2Sn2O7/NiAl-LDH heterojunction for boosting photocatalytic CO2 reduction under visible light

Fabrication of efficient photocatalysts with great visible light utilization ability, rapid carriers’ separation, and suitable redox potential is essential for improving photocatalytic CO2 reduction. Herein, flower-like microspheres Bi2Sn2O7/NiAl-layered double hydroxide (BSO/LDH) heterojunctions were prepared by hydrothermal process for CO2 reduction. The Bi2Sn2O7 nanoparticles were dispersed on NiAl-LDH nanosheets, with tight contact interface, which facilitated charges transfer and exposing more catalytic active sites. Results of photochemical deposition of metal/metal oxide demonstrated that interfacial charges transfer of the BSO/LDH followed Z-scheme mechanism, endowing more desired redox potential and more efficient carriers separation. The 30%-BSO/LDH showed the highest CO and CH4 yields of 37.91 and 1.18 μmol g−1 h−1 under visible light irradiation, 3.4 and 2.0 times higher than those from the NiAl-LDH, respectively. The main intermediates during CO2 reduction were carboxylate (COOH*) and aldehyde group (CHO*), and CO2 reduction pathways and mechanism were proposed accordingly. This study provided referential strategy for designing efficient heterojunction photocatalysts for CO2 conversion.

Facile in-situ construction of Z-scheme Bi6O5(OH)3(NO3)5·3H2O/Bi5O7I binary heterojunction composites for superior photocatalytic degradation of diverse persistent organic pollutants in water

Constructing efficient heterojunction photocatalysts via facile synthetic strategies is attractive from the viewpoints of improving photocatalytic efficiency and energy saving. Herein, a series of novel Bi6O5(OH)3(NO3)5·3H2O/Bi5O7I (BBN/BOI) Z-scheme binary heterojunction composites were successfully prepared by a facile in-situ growth of Bi6O5(OH)3(NO3)5·3H2O nanoplates on the surface of Bi5O7I as substrate material. The structural features, morphology and optical properties of the fabricated samples were investigated by various physicochemical methods. The BBN/BOI composites exhibited enhanced photocatalytic superiority in comparison with Bi6O5(OH)3(NO3)5·3H2O and Bi5O7I. The sample BBN/BOI-1 prepared with a Bi(NO3)3·5H2O/Bi5O7I feeding molar ratio of 1:1 displayed the best photocatalytic performance for 2-sec-butyl-4,6-dinitrophenol (DNBP) and Rhodamine B (RhB) degradation under simulated solar light illumination with good recycling characteristics. The Z-scheme charge transfer mechanism in BBN/BOI composites can not only facilitate the separation and migration of photoinduced electron-hole pairs but also retain strong redox reaction capacity, which contributes to promote the generation of h+ and •O2− as major active species responsible for the photocatalytic degradation of organic pollutants. The structural stability and photocatalytic activity of BBN/BOI system verifies its great potential for applicability in wastewater treatment.

Fabrication of novel Mn0.43Cd0.57S/ZnCo2O4 p-n heterojunction photocatalyst with efficient charge separation for highly enhanced visible-light-driven hydrogen evolution

The construction of efficient and low-cost photocatalytic systems is a major challenge in the field of photocatalysis. An efficient heterojunction photocatalyst designed for water splitting is also an interesting prospect in energy conversion. In this study, a novel Mn0.43Cd0.57S/ZnCo2O4 p-n heterojunction photocatalyst was prepared via a simple solvothermal method. Mn0.43Cd0.57S was loaded on the surface the of noble metal-free transition metal oxide ZnCo2O4 to prevent the agglomeration of particles, resulting in efficiently improving the photocatalytic performance of the material. Due to the Fermi level balance, the band bending of the two materials constructs a p-n heterojunction, which stimulates the transfer of photogenerated electrons from the CB of Mn0.43Cd0.57S to the CB of ZnCo2O4. The uniformly dispersed p-n heterojunction structure effectively suppresses the recombination of photoinduced charges and preserves stronger redox charges. As a result, the established Mn0.43Cd0.57S/ZnCo2O4 heterojunction showed the best photocatalytic hydrogen production concentration (92.1 mmol g−1 h−1), which was 4.7 times that of the original Mn0.43Cd0.57S (19.4 mmol g−1 h−1) and 54.2 times that of ZnCo2O4 (1.7 mmol g−1 h−1). This strategy will provide new insights into the development of new photocatalysts.

Fabrication of a Z-scheme CeO2/Bi2O4 heterojunction photocatalyst with superior visible-light responsive photocatalytic performance

In this study, a CeO 2 /Bi 2 O 4 Z-scheme heterojunction was prepared by using a facile hydrothermal method. After 40 min of visible-light irradiation, this composite photocatalyst displayed superior photocatalytic activity for removing levofloxacin and methyl orange than pure CeO 2 and Bi 2 O 4 , achieving the degradation efficiencies of 88.75% and 90.3%, respectively. According to the results of transient photocurrent response, electrochemical impedance spectroscopy, and photoluminescence, CeO 2 /Bi 2 O 4 heterojunction photocatalyst exhibited efficient photoinduced charges separation. The enhanced photocatalytic performance was due to synergy between efficient separation of photogenerated carriers and increased solar absorption. A Z-scheme heterojunction between CeO 2 and Bi 2 O 4 was formed, which was contributed by the well-matched band structure, facilitating the fast transfer and separation of carriers. The active species, including h + , O 2 · – , and ·OH, play key roles in the photodegradation reactions, demonstrated by electron spin resonance spectroscopy. High-performance liquid chromatography-mass spectrometry was used to identify the probable degradation path of levofloxacin. This work will benefit the design of efficient Z-scheme heterojunction photocatalysts for environmental remediation. • MO and LVF were used to evaluate the photocatalytic activities. • HAADF-STEM, ESR and HPLC-MS analysis were used to analyze the mechanism. • The separation of photoinduced carriers was testified by photocurrent, PL and SPV. • A possible mechanism of CeO 2 /Bi 2 O 4 Z-scheme heterojunction is proposed.