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Three distinct morphologies of Bi‐MOFs were innovatively employed as carriers, facilitating the formation of heterojunctions with BiPO4. Among these, the optimal photocatalytic performance was demonstrated by the type II heterojunction BiPO4/CAU‐17. Bi3+ competitively coordinated to crucially aid CAU‐17's transformation into a heterojunction, enhancing interfacial contact in BiPO4/CAU‐17. These photocatalysts effectively degraded dyes (RhB, MO, MB) and tetracycline (TC) under light exposure. RhB degradation was 3.33 times faster with BiPO4/CAU‐17 than BiPO4, 1.45 times faster than FCAU‐17, 1.36 times faster than FRCAU‐17, and 1.32 times faster than CAU‐17. Analyzing carrier density, Fermi level, and band structure through VB‐XPS, UV–VIS, and Mott–Schottky provided insights into enhanced separation of photoexcited electron–hole pairs. This study presents a novel approach to tackle the aggregation challenge of the wide‐bandgap material BiPO4 by using suitable MOFs as carriers. It offers valuable perspectives for the design and application of photocatalysts in environmental remediation. [ABSTRACT FROM AUTHOR]

Keeping in view of the hazardous application of tetracycline hydrochloride antibiotic, an efficient CoFe 2 O 4 /NiFe 2 O 4 heterojunction photocatalyst has been prepared hydrothermally by combining CoFe 2 O 4 and NiFe 2 O 4 nanoplates. The CoFe 2 O 4 /NiFe 2 O 4 composite with the improved photocatalytic activity can be employed for removal of tetracycline hydrochloride antibiotic, comparing to the bare CoFe 2 O 4 and NiFe 2 O 4. The optimized sample 5%-CoFe 2 O 4 /NiFe 2 O 4 shows the high photocatalytic degrading tetracycline with 76.1% removal efficiency in 60 min. These improved photocatalytic activities are attributed to the extended visible light absorption and enhanced charge separation following S-scheme route as confirmed from photoluminescence and electrochemical studies. From the charge trapping experiments, it is confirmed that superoxide radical and holes in the valence band of NiFe 2 O 4 with high thermodynamic energies are responsible for the photodegradation of the target pollutant. This work provides sufficient attention towards the preparation of low cost materials for the removal of highly hazardous pollutants being present in water. [ABSTRACT FROM AUTHOR]

Constructing heterostructures with efficient charge separation is a promising route to improve photocatalytic hydrogen production. In this paper, MoS x /CdS/KTaO 3 ternary heterojunction photocatalysts were successfully prepared by a two-step method (hydrothermal method and photo deposition method), which improved the photocatalytic hydrogen evolution activity. The results show that the rate of hydrogen evolution for the optimized photocatalyst is 2.697 mmol g−1·h−1under visible light, which is 17 times and 2.6 times of the original CdS (0.159 mmol g−1 h−1) and the optimal CdS/KTaO 3 (1.033 mmol g−1 h−1), respectively, and the ternary photocatalyst also shows good stability. The improvement on photocatalytic hydrogen evolution performance can be attributed to the formation of heterojunction between the prepared composite materials, which effectively promotes the separation and migration of photo-generated carriers. Amorphous MoS x acts as an electron trap to capture photogenerated electrons, providing active sites for proton reduction. This provides beneficial enlightenment for hydrogen production by efficiently utilizing sunlight to decompose water. • Successful preparation of a novel MoS x cocatalyst-modified CdS/KTO heterostructure without noble metals. • Composite catalysts exhibit excellent photocatalytic hydrogen evolution performance. • The hydrogen production rate of the composite is 17 times and 2.6 times that of pure CdS and CdS/KTO. • Amorphous MoS x acts as a trap to capture photogenerated electrons, providing active sites for proton reduction. [ABSTRACT FROM AUTHOR]

Construction of semiconducting metal‐organic framework based heterostructures is emerging as a promising strategy for enhancing their photocatalytic performances. Here, tetrapod‐like NH2‐MIL‐125@ZnS heterostructures with tunable heterojunction coverage and well‐matched band structure are synthesized as photocatalysts. When used for photocatalytic O2 reduction reaction, a heterojunction coverage of ≈45.1% leads to the best performance with a hydrogen peroxide production rate of ≈120 mm g−1 h−1, outperforming control samples with either larger or smaller heterojunction coverages and most reported MOF based photocatalysts in similar reaction systems. [ABSTRACT FROM AUTHOR]

• A novel BiOBr/BiOCOOH p-n heterojunction photocatalyst was prepared for the first time. • The composites exhibited significantly enhanced activity for Levofloxacin degradation. • The heterojunctions promote the photo-generated carriers transmission and separation. BiOBr/BiOCOOH p-n heterojunction photocatalysts were fabricated via a two-step solvothermal method. The photocatalytic performance of as-prepared heterojunctions was evaluated under visible light for the degradation of Levofloxacin. The composite samples exhibited significantly accelerative degradation rate compared to both pure catalysts (BiOBr and BiOCOOH). Besides, the apparent rate constant of the optimal sample for Levofloxacin degradation was 1.7 and 144.8 times higher than that of pure BiOBr and BiOCOOH. The improved activity can be attributed to the high charge separation efficiency. Furthermore, quenching experiment was also carried out. The results indicated that the photogenerated hole (h+) and superoxide radical (O 2 −) were the dominant reactive radicals responsible for the degradation of Levofloxacin. Cycling test also reveals that the sample owned good stability. In the end, a possible photocatalytic degradation mechanism was proposed. This work would provide a good example for the design and preparation of bismuth based p-n heterojunction composite photocatalysts with high visible-light-responsive performance for environment purification. [ABSTRACT FROM AUTHOR]

Novel CdS/La 2 Ti 2 O 7 /NiS 2 ternary composite photocatalysts without noble metal were successfully constructed by a simple hydrothermal method. Under visible light irradiation (λ > 400 nm), the optimal CdS/La 2 Ti 2 O 7 /NiS 2 composite produced H 2 at a rate of about 12.77 mmol g−1 h−1, which was 84 times as high as that of pure CdS. This performance enhancement can be attributed to the formation of multiple heterojunctions (including CdS/NiS 2 , CdS/La 2 Ti 2 O 7 and CdS/La 2 Ti 2 O 7 /NiS 2 interface structures) between the three components in the as-prepared CdS/La 2 Ti 2 O 7 /NiS 2 composites. The formed multiple heterojunctions help to separate electron-hole pairs more quickly and efficiently, thus greatly increasing the photocatalytic activity of the CdS/La 2 Ti 2 O 7 /NiS 2 composites. This is very important for the utlization of solar energy for water splitting. • CdS/La 2 Ti 2 O 7 /NiS 2 ternary composite photocatalysts were prepared for the first time. • The composites exhibited greatly enhanced photocatalytic hydrogen evolution rate. • Multiple heterojunctions between NiS 2 , La 2 Ti 2 O 7 and CdS contributed to the high activity. [ABSTRACT FROM AUTHOR]

Highlights • A novel Bi 2 MoO 6 /BiOCOOH heterojunction photocatalyst was prepared for the first time. • The composites exhibited significantly enhanced activity for Ofloxacin degradation. • The heterojunctions promote the photo-generated carriers transmission and separation. Abstract Bi 2 MoO 6 /BiOCOOH heterojunction photocatalysts were successfully fabricated via a facile solvothermal method. The as-fabricated composite photocatalysts displayed greatly accelerated degradation rate toward Levofloxacin under visible-light irradiation. Typically, the incorporation ratio of Bi 2 MoO 6 had apparent effect on the performance of the heterojunction photocatalysts. The apparent rate constant of optimal sample for Levofloxacin degradation was 11.3 and 241.3 times higher than that of pure Bi 2 MoO 6 and BiOCOOH, respectively. The main reason for the improved performance was ascribed to the formation of heterojunctions between the two components. Results of the quenching studies indicated that both photogenerated hole (h+) and superoxide radical (·O 2 −) were main reactive radicals responsible for the degradation of Levofloxacin. Herein, the Bi 2 MoO 6 /BiOCOOH heterojunction could be a favorable material for visible-light-utilized water purification. Graphical abstract Image, graphical abstract Bi 2 MoO 6 /BiOCOOH heterojunction photocatalysts were successfully fabricated via a facile solvothermal method for the first time. The as-obtained photocatalysts showed significantly enhanced activity for Ofloxacin degradation under visible light irradiation. The optimum apparent rate constant reached up to 11.3 and 241.3 times as that of pure Bi 2 MoO 6 and BiOCOOH, respectively. [ABSTRACT FROM AUTHOR]

The establishment of Z-scheme heterojunction with ascendant redox ability presents a potential application prospect in the development of efficient photocatalysts for environmental purification. Herein, the Z-scheme Fe 3 O 4 /BiOCl/BiOBr heterostructure composite with preeminent retrievability was obtained using a facile solvothermal method. The various physicochemical properties of the acquired materials were explored through systematic characterizations. The Fe 3 O 4 /BiOCl/BiOBr ternary photocatalyst possessed excellent photocatalytic degradation efficiency (85%) towards tetracycline (TC) under simulated sunlight irradiation. Given the results of capturing experiments, superoxide radicals (·O 2 −) and holes (h+) made predominant contributions to the photodegradation reaction. The enhanced photocatalytic activity of Fe 3 O 4 /BiOCl/BiOBr was mostly resulted in the framework of Z-scheme heterojunction, which led to the efficient migration of the photoinduced carriers. In addition, Fe 3 O 4 /BiOCl/BiOBr exhibited good recyclability and stability while retaining its high photocatalytic activity. It was expected that this work would create a new opportunity to fabricate magnetically recyclable photocatalysts with Z-scheme heterojunction for efficient removal of antibiotic pollutants. [Display omitted] [ABSTRACT FROM AUTHOR]

A simple solvothermal method was reported to prepare a novel BiOCl/BiOCOOH heterojunction photocatalyst. The as prepared composite photocatalysts exhibited significantly enhanced photocatalytic activity for RhB degradation under simulated sunlight. The composite photocatalysts even exhibited much higher activity than that of P25. The effect of the BiOCl amount on the activity of the composites was also investigated. Results showed that apparent rate constant of the optimal sample was 3, 7.7 and 35.9 times as high as that of P25, BiOCl and BiOCOOH, respectively. The composites would be promising material for the removal of contaminants in water. [ABSTRACT FROM AUTHOR]

The construction of a Z-scheme heterojunction favors the improvement of the photocatalytic activity of photocatalysts. Herein, the LaVO 4 /Bi 3 O 4 Cl Z-scheme heterojunction was designed reasonably by the method of in situ growth. The obtained heterojunction was further used as a photocatalyst for the degradation of ofloxacin (OFX), an antibiotic, in wastewater. The degradation efficiency of OFX by the optimal sample (LBC-2) was 94.3 % and the values of k were about 114.7 and 2.4 times those of LaVO 4 and Bi 3 O 4 Cl, respectively. In addition, LBC-2 maintained high activity after 4 cycles. The significantly reduced recombination rate of carriers in LBC-2 was reflected by the results of the photoluminescence (PL), photocurrent (PC), and electrochemical impedance spectroscopy (EIS) studies. The degradation pathways of OFX were proposed accounting to the intermediates detected by liquid chromatography-mass spectroscopy (LC-MS). Toxicity estimations showed that the toxicity of some intermediates decreased. This work provides new insight into the development of Z-scheme photocatalysts for the removal of antibiotics as pollutants. • Novel Z-scheme LaVO 4 /Bi 3 O 4 Cl composite photocatalysts were synthesized. • LaVO 4 /Bi 3 O 4 Cl composites exhibited excellent activity for ofloxacin degradation. • The apparent rate constant for ofloxacin degradation was about 114.7 and 2.4 times as that of LaVO 4 and Bi 3 O 4 Cl. • Z-scheme heterojunction boosted the fast transfer of charge carriers. • The degradation pathway of ofloxacin was deduced. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rod-like TiO 2 -based composite loaded with g-C 3 N 4 (denoted as RT/CN) is fabricated by alkaline hydrothermal method. • The removal efficiency of high-chroma methylene blue solution by RT/CN is regulated by controlling the amount of g-C 3 N 4. • RT/CN-10 (10 mg g-C 3 N 4 loading) has a significant removal rate upgrade under adsorption-photocatalysis mechanism. • The formation of RT/CN heterojunction with the large specific surface area is the key reason for the improved performance. In this study, a simple alkaline hydrothermal method for synthesizing the rod-like TiO 2 -based composite loaded with g-C 3 N 4 (denoted as RT/CN) to efficiently remove the high-chroma organic pollutants is presented. The removal efficiency of high-chroma methylene blue (MB) solution by RT/CN is regulated by controlling the amount of g-C 3 N 4. The results show that RT/CN-10 (10 mg g-C 3 N 4 loading) has a significant removal rate upgrade, i.e., 22.7 times than that of TiO 2 , and 20.6 times than that of g-C 3 N 4 under adsorption-photocatalysis mechanism. The key reason for the improved performance is related to the large specific surface area, which accounts for the adsorption of pollutants and the utilization of visible light. Moreover, the formation of RT/CN heterojunction contributes to the rapid separation and transfer of photogenerated electron-hole pairs under visible light. In brief, the facile synthesis strategy for heterojunction based on adsorption-photocatalysis mechanism displays high potential of practical application in the removal of high-chroma organic pollutants. [ABSTRACT FROM AUTHOR]

• Novle Z-scheme Bi 4 O 5 I 2 /Bi 3 TaO 7 composite photocatalysts were synthesized. • The photocatalyst exhibited high performance for levofloxacin degradation. • The apparent rate constant for levofloxacin degradation was 4.1 and 14.1 times as that of Bi 4 O 5 I 2 and Bi 3 TaO 7. • The mechanism on the enhanced performance was discussed deeply. Constructing a Z-scheme heterojunction with excellent oxidation–reduction ability is an effective way to develop high-efficiency photocatalysts for environmental pollution control. Herein, the synthesis and characterization of a novel Z-scheme Bi 4 O 5 I 2 /Bi 3 TaO 7 heterojunction photocatalyst are reported, and the photocatalytic performance of samples is evaluated by the degradation of levofloxacin (LVFX) under visible light. The optimal composite photocatalyst (BIT-3) showed the highest photocatalytic activity, and its apparent rate constants were 4.09 and 14.13 times as that of Bi 4 O 5 I 2 and Bi 3 TaO 7 , respectively. The improvement of photocatalytic activity can be attributed to the formation of 2D/0D heterojunction (conformed by TEM) between Bi 4 O 5 I 2 and Bi 3 TaO 7 , which effectively promotes the separation and migration of photogenerated electron-hole pairs (conformed by PL and photocurrent), and retains photogenerated carriers with strong redox ability. According to the results of radical capture and energy band theory, the photocatalytic reaction mechanism of direct Z-scheme Bi 4 O 5 I 2 /Bi 3 TaO 7 was proposed. The intermediate products in the degradation process of LVFX were determined by liquid chromatography-mass spectrometry (LC-MS), and the possible degradation pathway was put forward. [ABSTRACT FROM AUTHOR]

The direct Z-scheme Bi 3 TaO 7 /Mn 0.5 Cd 0.5 S (MCS) composite photocatalyst was successfully constructed by an in-situ growth method. The performance for levofloxacin degradation by the composite catalysts under visible light irradiation was studied. The k value of BMCS-3 is the highest (0.05813 min−1), which is 3.1 times larger than that of BTO (0.01846 min−1) and 7.0 times larger than that of pure MCS (0.00825 min−1). The photocurrent (PC), photoluminescence (PL) spectroscopy and electrochemical impedance spectroscopy (EIS) suggested that the migration rate of photogenerated electrons and holes were greatly improved after the combination of Bi 3 TaO 7 and Mn 0.5 Cd 0.5 S. On one hand, the separation efficiency of photogenerated electron-hole pairs of the composite material was improved due to the formation of Z-scheme heterojunction. On the other hand, the redox ability of photogenerated electron-hole pairs was maintained, which helped the composite material to exhibit enhanced photocatalytic performance. Meanwhile, the possible pathways of levofloxacin degradation and the toxicity of the produced intermediates were investigated. [Display omitted] • Novel Z-scheme Bi 3 TaO 7 /Mn 0.5 Cd 0.5 S composite photocatalysts were synthesized. • The photocatalyst exhibited high performance for the degradation of levofloxacin. • The rate constant improved by a factor of 3.1 and 7.0 compared to Bi 3 TaO 7 and Mn 0.5 Cd 0.5 S. • The mechanism on the enhanced performance was discussed deeply. • The deductive degradation pathway of levofloxacin was also proposed. [ABSTRACT FROM AUTHOR]

• Cu 2 O/Ti 3 C 2 T x heterojunction composites were prepared by in situ hydrothermal growth method. • In situ growth endows the Cu 2 O/Ti 3 C 2 T x heterojunction contact interface. • Cu 2 O/Ti 3 C 2 T x heterojunction composites sharply enhanced the photocatalytic activity. Photocatalytic CO 2 reduction has been viewed as a promising approach to relieve the energy crisis and green-house effect. Cheap and high performance cocatalyst is an effective approach to enhance the photocatalytic activity. Ti 3 C 2 T x (MXene) is a new family of 2D layered materials, which can be served as an electron conductor. In this work, Cu 2 O/Ti 3 C 2 T x heterojunction composites were prepared by in situ hydrothermal growth method. Cu 2 O/Ti 3 C 2 T x with the different percentages of ultrathin Ti 3 C 2 T x (2, 5, 10, 20 and 30 mg) nanosheet in the heterostructured catalysts are noted as CuTi-X (X = 2, 5, 10, 20, 30). As prepared CuTi-10 exhibits the highest photocatalytic CO 2 reaction activity (17.55 μmol·g−1·h−1 for CO and 0.96 μmol·h−1·g−1 for CH 4), which is 3.1 and 4.0 times higher than that of pure Cu 2 O (5.73 μmol·g−1·h−1 for CO and 0.24 μmol·g−1·h−1 for CH 4 , respectively). The advantage of the in situ growth endows the Cu 2 O/Ti 3 C 2 T x heterojunction contact interface, which is conductive to the separation of photogenerated electrons-hole pairs. The main reason is analysed and can be attributed to that Ti 3 C 2 T x can served as an electron acceptor due to its excellent conductive properties, rendering that more photo generated electrons attend the CO 2 reduction reaction. This provides a strategy to construct the Cu 2 O/Ti 3 C 2 T x heterojunction for photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

LaFeO 3 /Bi 3 NbO 7 p-n heterojunction photocatalysts were prepared successfully through an in-situ growth method. The phase structure, optical property, morphology and microstructures of the obtained samples were studied by X-Ray diffractometer (XRD), Ultraviolet–visible absorption spectrum (UV–vis DRS), photoluminescence (PL) spectroscopy, transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM). The visible light responsive photocatalytic activity of as-obtained samples were investigated by the photo-reduction of Cr (Ⅵ). The effects of preparation conditions (proportion of BNO/LFO and temperature) on the activity were studied. Results showed that the as-obtained BNO-LFO-200-5 composite behaved the best photocatalytic activity (with rate constant of 0.0212 min−1) among all the obtained samples. The rate constant was about 42.4-times and 17.7-times as that of pristine BNO (0.0005 min−1) and LFO (0.0012 min−1), respectively. The enhanced photocatalytic property of the as-prepare LaFeO 3 /Bi 3 NbO 7 composites can be ascribed to the formation of p-n junction between BNO and LFO, which significantly increased the separation efficiency of photo-excited electron-holes. • A novel LaFeO 3 –Bi 3 NbO 7 p-n heterojunction photocatalyst was prepared for the first time. • The composites exhibited significantly enhanced activity for Cr (Ⅵ) photocatalytic reduction. • The heterojunctions promote the photo-generated carriers transmission and separation. [ABSTRACT FROM AUTHOR]

In order to have an insight into the internal electric field (IEF) of BiOCl(001), we design a novel wide-spectrum responsive BiOI(010)/BiOCl(001) heterojunction composite by a facile method. The system could shield the photocatalysis of BiOCl(001) under visible light due to its large Eg (3.41 eV), thus specifying role of the BiOCl(001) in BiOI(010)/BiOCl(001). The XRD and TEM results show that the composites exhibit a coexistence of both tetragonal BiOI(010) and BiOCl(001) phases. The as-prepared BiOI(010)/BiOCl(001) samples exhibit higher BET surface area than those of BiOI(010) and BiOCl(001). The UV, visible, and simulated sunlight photocatalytic activities of composites for methyl orange (MO) were greatly enhanced compared to either pure BiOI(010) or BiOCl(001). Especially, under the visible light, an enhancement of photocatalytic activity (MO, acid fuchsin) was found for BiOI(010)/BiOCl(001), suggesting an IEF of BiOCl(001) plays a key role on the photo-generated carrier separation of BiOI(010). Specifying the IEF role of BiOCl(001) in BiOI(010)/BiOCl(001) is expected to inspire the further exploration, developing efficient photocatalysts with potential applications. [ABSTRACT FROM AUTHOR]

One of the current key issues in the photocatalysis is to obtain the band alignment of coupled semiconductor experimentally, which is the most significant aspect for understanding the efficient photocatalytic activity precisely. In this article, a BiVO 4 /BiOI{001} heterojunction was detected by the transmission electron microscopy (TEM). The results of electrochemical impedance spectroscopy (EIS) reveal that a higher efficiency of charge immigration across the electrode/electrolyte interface for the BiVO 4 /BiOI{001}. In addition, the electron lifetime was investigated by the Bode phase plots, which are responsible for the observed photocatalytic behaviors. As a result, the photocatalytic activities for rhodamine B (RhB) degradation and iodine ion oxidation are remarkably increased compared to the individual BiVO 4 and BiOI{001}. In fact, a direct band alignment in the BiVO 4 /BiOI{001} does not give well a logical interpreting on its photocatalytic behavior. However, through the valence-band offset formula, we demonstrated the exact band alignment of corresponding components in the BiVO 4 /BiOI{001}. This band alignment was further confirmed by the PL spectra, which CM2 with photo-oxidation (Mn 2+ ) is red shift and CM2 with photo-reduction (Ag + ) is blue shift compared with CM2. [ABSTRACT FROM AUTHOR]

A 3D hierarchical RP/BP/BiOCOOH double heterostructures with abundant oxygen vacancies (OVs) was obtained by hydrothermal process and its photocatalytic activity was investigated by degradation of TC-HCl with different light sources and various natural water. The physicochemical characteristics of RP/BP/BiOCOOH heterojunctions were systematically characterized via TEM, XPS, EPR, EIS et al. Compared with BiOCOOH, the photocatalytic activity of RP/BP/BiOCOOH was obviously enhanced. Under simulated solar light irradiation, 60.5% of TC-HCl was removed by 3%RP/BP/BiOCOOH. And the rate constant of 3%RP/BP/BiOCOOH was 2.95 times than that of BiOCOOH. Traces of small molecular organics were beneficial to improve photocatalytic efficiency. The process of photocatalytic degradation and the cytotoxicity of intermedia products of TC-HCl were discussed via HPLC-MS, 3D-EEM, and antibacterial properties test. Based on the results of trapping experiments and ESR tests, •OH and •O 2 − were the most significant reactive oxygen species. The enhanced photocatalytic activity was ascribed to two reasons: 1 double heterojunctions structure enhanced the separation efficiency of carriers, 2 the introduction of OVs and BP/RP expanded the response range of light. This work provides a feasible strategy that non-metallic element semiconductor is used to modify the wide band gap semiconductor to enhance the photocatalytic efficiency. [Display omitted] • Abundant oxygen vacancies on BiOCOOH were generated via BP/RP introduction. • The photocatalytic degradation of TC-HCl was implemented with different light sources. • Hole sacrifice agents greatly improved the quantum efficiency, which leading to a high photocatalytic efficiency. • Double heterojunctions between BiOCOOH and BP/RP accelerated the separation efficiency of carriers. [ABSTRACT FROM AUTHOR]

• Layered bismuth-based (LBB) photocatalytic materials are systematically summarized. • Four types of LBB photocatalysts with different crystal structures are introduced. • Various modification strategies for improving photocatalytic activity are discussed. • Diversified photocatalytic applications of LBB materials are systematically summarized. Semiconductor photocatalysis has received considerable interdisciplinary attentions and research interests owing to its versatile applications. Layered bismuth-based (LBB) materials, featured by layered structure built by [Bi 2 O 2 ]2+ slices and interleaved anions or/and anionic groups, show huge potentials in solar energy catalytic conversion due to their unique crystal structure, diverse composition, rich atomic coordination and favorable hybrid electronic band structure. In this review, we provide a comprehensive, systematic and timely summary on the LBB-based materials applied in photocatalysis, which start with the classification, characteristics, and synthesis. Subsequently, LBB photocatalysts are classified into Sillén-structured, Aurivillius-structured, Sillén-Aurivillius-structured and Sillén/Aurivillius-related structured photocatalysts based on the interleaved unit types, and all kinds of strategies for improving their photocatalytic performance are presented in details, including microstructure regulation (morphology control and facet engineering), crystal structure regulation (elements doping, crystal vacancy creation, layered structure regulation and polar enhancement) and heterojunction construction (semiconductor/LBB heterojunctions, carbon/LBB composites, polymer/LBB composites and multicomponent heterojunctions). Comprehensive photocatalytic applications of LBB materials, including pollutants purification, bacterial disinfection, water splitting, CO 2 reduction, N 2 reduction, H 2 O 2 production/decomposition, selective organic synthesis, photoelectrocatalysis, as well as photocatalysis-assisted piezocatalysis and electrochemical energy storage are introduced in the respective type. Finally, concluding perspectives and outlook towards the future development of LBB photocatalysts are provided. This review is expected to furnish a sweeping guideline for the in-depth understanding and rational design of LBB photocatalysts, and inspire new concepts and advancements in other booming fields for energy and environmental applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The photocatalysis performance of g-C 3 N 4 was enhanced by coupling oxidized Ti 2 C 2. • An all-solid-state Z-scheme heterojunction was form in CN/TC composite. • CN/TC composite showed high photocatalytic reactivity for U(VI) reduction. The photocatalytic reduction of U(VI) has been regarded as an efficient method for separating uranium from aqueous solution. This study is devoted to develop a catalyst with high photocatalytic efficiency for the reduction of U(VI). The decoration of Ti 3 C 2 on carbon nitride (CN) remarkably improved the adsorption affinity for U(VI), the optical absorbance, and the separation efficiency of the photo-generated electrons and holes, which subsequently enhanced the photocatalytic performance for U(VI) reduction. Compared to pristine CN, the reaction constant of CN/TC-2 for the reduction of U(VI) improved by 14.05 times fold. Owing to the formation of TiO 2 on Ti 3 C 2 surface, an all-solid-state Z-scheme heterojunction was formed, which was key for the efficient separation of charge carriers and the enhancement of the photocatalytic reactivity of CN/TC composites. During the photocatalytic reactions, U(VI) was reduced to U(IV), forming UO 2+x (x < 0.25) deposits, and •O 2 − acted as the dominant reduction species. [ABSTRACT FROM AUTHOR]

A p-n-type Bi 5 O 7 I-modified porous g-C 3 N 4 nano-heterojunction is synthesized via a simple preparation technique using the template method and annealing-hydrothermal co-deposition method. The results of SEM, EDS, elemental mapping, XRD, TEM, XPS and FT-IR imply that the Bi 5 O 7 I nanoparticles were successfully deposited on the surface of the g-C 3 N 4 nanosheets. The photocatalytic activity of the as-prepared p-n-type nano-heterojunction remarkably exhibits an enhancement of 30 times that of the unmodified samples. Furthermore, the photocatalytic degradation enhancement mechanism has been studied, which could be ascribed to the p-n-type nano-heterojunction and lamellar-porous structure of the g-C 3 N 4 . [ABSTRACT FROM AUTHOR]

In the present work, a series of layered BiOBr/g-C 3 N 4 heterojunction photocatalysts were prepared via a simple reflux process, and their photocatalytic performance was investigated by the degradation of rhodamine B (RhB) and bisphenol A (BPA) under visible light irradiation. It was found that BiOBr nanoplates were deposited on the external surface of g-C 3 N 4 nanosheets (CNNS) and the tightly contacted interface was formed between two components, giving rise to a 2D porous layered heterojunction structure with a high specific area. It was found that BiOBr nanoplates coupled with the proper amount of CNNS exhibited an excellent photocatalytic performance due to the combined effects of layered heterojunction, high specific surface area and porous structure, which lead to the high efficiency of light harvesting and charge separation. The active species of OH is the most crucial one while h + and O 2 − contributed to a lesser extent in RhB and BPA photocatalytic degradation. Based on the direct evidence of the formed OH, O 2 − and h + active species detected by active species capture experiment and ESR spectra, a Z-scheme photocatalytic mechanism was proposed for the charge separation. The present work may provide an insight for designing novel layered Z-scheme heterojunction photocatalysts with a high performance. [ABSTRACT FROM AUTHOR]

Although photocatalytic degradation is an ideal strategy for cleaning environmental pollution, it remains challenging to construct a highly efficient photocatalytic system by steering the charge flow in a precise manner. In this study, a novel atomic scale g-C 3 N 4 /Bi 2 WO 6 heterojunction (UTCB) constructed by ultrathin g-C 3 N 4 nanosheets (ug-CN) and monolayer Bi 2 WO 6 nanosheets (m-BWO) was successfully prepared by hydrothermal reaction. The UTCB heterojunctions were characterized by various techniques including XRD, TEM, AFM, BET measurements, UV–vis spectrometry, and XPS. The results indicated that UTCB heterojunctions were assembly of m-BWO on ug-CN and presented high separation efficiency of photogenerated carriers. Under visible light irradiation, the optimum molar ratio of ug-CN/m-BWO (1:4, UTCB-25) reached almost 96.1% removal efficiency of IBF within 1 h, which was about 2.7 times as that of pure m-BWO. The photocatalytic mechanisms of UTCB-25 were revealed, suggesting that the synergistic effect of UTCB-25 heterojunction with strong interfacial interaction promoted the photoinduced charge separation. According to the LC–MS/MS, five photodegradation pathways of IBF under visible light irradiation were proposed. This study could open new opportunities for the rational design and a better understanding of atomic scale two dimensions/two dimensions (2D/2D) heterojunctions in environmental or other applications. [ABSTRACT FROM AUTHOR]

The x Fe 2 O 3 / y BiOCl ( x/y , molar ratio) composites are prepared via a facile hydrothermal process, in which the uniform Fe 2 O 3 nanocubes are well deposited on the BiOCl nanosheets. The x Fe 2 O 3 / y BiOCl shows much higher activities than BiOCl or Fe 2 O 3 for the degradation of rhodamine B (RhB) and methyl orange (MO). Specifically, the degradation rate of the 5Fe 2 O 3 /100BiOCl catalyst is 7.2 and 3.7 times as high as those of the bare BiOCl for MO and RhB, respectively. This has been mainly attributed to the formation of p/n Fe 2 O 3 /BiOCl heterojunctions. [ABSTRACT FROM AUTHOR]

Reducing carbon dioxide (CO 2) as fuel by photocatalysis is one of the effective methods in addressing the issues of fossil fuel crisis and greenhouse effect. Here, a novel p-n heterojunction made up of NiO nanosheets and g-C 3 N 4 nanowires has been effectively fabricated on a large scale for the photocatalytic conversion of CO 2 to CO and CH 4. The morphologies, structures and composition of the NiO/g-C 3 N 4 were characterized, which confirmed the being of the p-n junction between NiO nanosheets and g-C 3 N 4 nanowires. The improved photocatalytic activities of CO 2 reduction over NiO/g-C 3 N 4 can come from the broadened light response range and the formation of the p-n junction that could deter the rapid recombination of electrons and holes. The possible photocatalytic mechanism of CO 2 reduction reaction has been presented. Moreover, a novel NiO/g-C 3 N 4 photocatalyst exhibits considerable stability for CO 2 reduction. [Display omitted] • The NiO/g-C 3 N 4 heterojunctions were assembled. • NiO/g-C 3 N 4 enhanced activities for CO 2 photoreduction. • The synergistic effect of matching band and heterojuction improved the charge separation efficiency. [ABSTRACT FROM AUTHOR]

• A novel W 18 O 49 @g-C 3 N 4 core-shell heterojunction was fabricated for the first time. • The g-C 3 N 4 shell can effectively inhibit the deactivation of oxygen vacancies in internal W 18 O 49. • The protective mechanism of oxygen vacancies has been studied and proposed. • A novel design strategy for stable nonstoichiometric semiconductor photocatalyst is developed. Nonstoichiometric plasmon semiconductors own excellent NIR absorption due to their unique LSPR effect, which shows great promise in the design and preparation of sunlight driven photocatalysts. The LSPR in such plasmon materials originates from the carrier collective oscillations of the lattice vacancies, so the stability of lattice vacancies determines the persistence of LSPR effect. Take W 18 O 49 for example, the oxygen vacancies that provide LSPR effect will be oxidized and disappear after being used or exposed in the air for a long time, leading to the losing of NIR absorption ability. In order to inhibit the deactivation of oxygen vacancies, in this work, a layer of g-C 3 N 4 shell is wrapped around the surface of W 18 O 49 to isolate oxygen contact. The experiments proved that this strategy can greatly improve the stability of oxygen vacancies in W 18 O 49 , and make it maintain almost the same LSPR intensity after three-day aging experiment. [ABSTRACT FROM AUTHOR]

• Sparse or assembled Au nanocrystals are precisely modulated into COFs matrix. • Light absorption and charge transfer are enhanced in all Au/COFs composites. • Interfacial reaction kinetics are greatly favored in sparsely dispersed Au/COFs. • Boosted activity and selectivity are achieved in photo-oxidation/reduction cases. Plasmonic Au nanocrystals (NCs) are incorporated into covalent organic frameworks (COFs) with precisely modulated distributions to improve the efficiency of electron-hole separation and optimize the charge-carrier utilization. Specifically, through balancing the rate of dynamic covalent reactions and assembly of NCs, sparsely dispersed Au NCs (AuSP/COFs) or the close packed ones (AuCP/COFs) in COFs are fabricated, in which the contributions of electron acceptors/cocatalysts on the catalytic properties of Au/COFs composites are addressed by EPR, PL, and electrochemical measurements. Au3SP/COFs shows the best photocatalytic performances in photodegradation of RhB (remove >95 % in 120 min, k w =1.8 min−1 g−1) and dehalogenation of phenacyl bromide (conversion >99 %, selectivity of acetophenone ∼92.8 %) under visible light irradiation, which are associated with accelerated electron transfer, increased available Au/COFs Schottky junctions and boosted interfacial reaction kinetics. Overall, this work contributes to the fundamental understanding of the how spatial distributions of NCs in COFs affect the photocatalytic performances. [ABSTRACT FROM AUTHOR]