Efficient Heterojunction Photocatalysts Research Articles

Porous hollow Ag/Ag2S/Ag3PO4 nanocomposites as highly efficient heterojunction photocatalysts for the removal of antibiotics under simulated sunlight irradiation

Antibiotic pollutants are a serious and growing threat to human health and the environment that efficient measures must be taken to eliminate them. Here, we report the facile fabrication of porous hollow Ag/Ag2S/Ag3PO4 heterostrucutres for efficient photocatalytic degradation of tetracycline under simulated sunlight irradiation. The morphology manipulation and hetero-nanocomposites construction through a coprecipitation-refluxing approach were applied to enhance the photocatalytic performance of the Ag/Ag2S/Ag3PO4 products. The photodegradation outcomes indicated that the heterojunction Ag/Ag2S/Ag3PO4 photocatalyst with a suitable band gap energy of 2.17 eV, has better degradation performance (∼95%) than individual Ag2S and Ag3PO4 structures after 120 min of simulated sunlight irradiation, even after five recycles. The good photocatalytic activity of Ag/Ag2S/Ag3PO4 nanocomposites could be mainly attributed to the unique hierarchical architectures, promoted visible-light harvesting, reduced a recombination and boosted separation of electron-hole pairs originated from the as-formed heterojunctions. Moreover, we proposed a photocatalytic degradation mechanism based on the radical scavenging results, which disclosed that the •O2− and •OH species perform essential tasks for the photodegradation of antibiotics by Ag/Ag2S/Ag3PO4 nanocomposites.

A novel AgCl-based visible-light photocatalyst through in-situ assembly of carbon dots for efficient dye degradation and hydrogen evolution

A novel efficient AgCl-based heterojunction photocatalyst was synthesized by in-situ electrostatic-assembly of carbon dots (CDs) for the first time. Distinct from the physical blending between CDs and AgCl (CDs + AgCl), CDsAg was heterojuncted into AgCl in this work. The resulting CDsAg-AgCl photocatalyst was endowed with significantly enhanced visible-light photocatalytic performances in both dye degradation and hydrogen evolution With a Cl−/Ag+ molar percentage of 90% and visible light irradiation, methyl orange (MO) was degraded within 30 min with a degradation efficiency of 0.069 min−1, which was about 42.3, 8.9 and 10.6 times higher than those of CDs, AgCl and CDsAg+AgCl, respectively. It also yielded an excellent hydrogen evolution efficiency of 617.4 μmolg−1 h−1, exhibiting a high potential in the field of energy regeneration. Moreover, it showed a good reusability and stability after 5 recycles for both degradation and hydrogen evolution. In addition, a possible photocatalytic mechanism was proposed, where CDsAg-AgCl heterojunction structure facilitated the transfer-separation of photo-generated electron-hole pairs to promote the photocatalytic performance. This work could provide a new route to prepare novel high-efficient photocatalysts for the energy and environmental application.

Boosting the photocatalytic hydrogen evolution performance of monolayer C2N coupled with MoSi2N4: density-functional theory calculations.

Very recently, an important two-dimensional material, MoSi2N4, was successfully synthesized. However, pure MoSi2N4 has some inherent shortcomings when used in photocatalytic water splitting to produce hydrogen, especially a low separation rate of photogenerated electron-hole pairs and a poor visible light response. Interestingly, we find that the MoSi2N4 can be used as a good modification material, and it can be coupled with C2N to form an efficient heterojunction photocatalyst. Here, using density functional theory, a type-II heterojunction, C2N/MoSi2N4, is designed and systematically studied. Based on AIMD simulations and phonon dispersion verification, C2N/MoSi2N4 shows sufficient thermodynamic stability. As well as its perfect interface electronic properties, its large interlayer charge transfer and good visible light response lay the foundation for its excellent photocatalytic performance. In addition, the oxidation and reduction potentials of the C2N/MoSi2N4 heterojunction not only can meet the requirements of water splitting well but can also maintain a delicate balance between oxidation and reduction reactions. More importantly, the |ΔGH*| value of the C2N/MoSi2N4 heterojunction is very close to zero, indicating great application potential in the field of photocatalytic water splitting. In brief, our research paves the way for the design of future MoSi2N4-based efficient heterojunction photocatalysts.

A novel design of SiH/CeO2(111) van der Waals type-II heterojunction for water splitting.

Searching for economical low-dimensional materials to construct the highly efficient type-II heterojunction photocatalysts for splitting water into hydrogen is very strategic. In this study, using the first-principles calculations, we construct a novel SiH/CeO2(111) type-II heterojunction with a very small lattice mismatch of less than 1%. Based on AIMD simulation and phonon dispersion calculations, the SiH/CeO2(111) heterojunction reveals sufficient stability, and is easy to synthesize. Due to the vdW interaction between SiH and CeO2(111) components, electron and hole accumulation regions form at the heterojunction interface, which is very conducive to the separation of photoexcited electron-hole pairs. Besides, the SiH/CeO2(111) heterojunction has good visible light response, and even a strong absorption peak of up to 8.7 × 105 cm-1 in the high-energy visible region. More importantly, the SiH/CeO2(111) heterojunction exhibits good OER and HER performance because its oxidation and reduction potentials well meet the requirements of water splitting. Consequently, SiH/CeO2(111) is a potential photocatalyst for splitting water to hydrogen.

Facile solvothermal synthesis of a Z-Scheme 0D/3D CeO2/ZnIn2S4 heterojunction with enhanced photocatalytic performance under visible light irradiation

Reasonable designing heterojunction photocatalysts is an effective way to improve the photocatalytic activity of semiconductor. Herein, the efficient binary heterojunction photocatalyst formed between zero-dimensional (0D) CeO2 nanoparticles and three-dimensional (3D) floriated shaped ZnIn2S4 microspheres was synthesized by a simple solvothermal method. A series of analytical methods were used to characterize the optical properties and morphology of CeO2/ZnIn2S4 composite photocatalysts. Photodegradation experimental results showed that CeO2/ZnIn2S4 composites displayed strong photocatalytic activity for the degradation of tetracycline (TC) with heavy concentrations (30 mg/L). The as-obtained optimum 10 wt% CeO2/ZnIn2S4 sample displays high degradation efficiency of 91% within 120 min, which is about 12.9 and 3.03 times higher than that of pure CeO2 and ZnIn2S4, respectively. The enhanced photocatalytic activity is ascribed to the formation of Z-scheme heterojunction between CeO2 and ZnIn2S4, which contributes to the increased surface area, enhanced redox ability and high separation efficiency of photogenerated charge carriers. The degradation pathways and intermediate products of TC over CeO2/ZnIn2S4 composite were analyzed by liquid chromatography-mass spectrometry (LC/MS) measurement. This study provides a new approach to prepare of efficient 0D/3D-based Z-scheme heterojunction photocatalysts.

BiOI/Bi2O2[BO2(OH)] heterojunction with boosted photocatalytic degradation performance for diverse pollutants under visible light irradiation

Construction of heterojunction photocatalyst is a very useful approach to enhance photocatalytic activity. In particular, the coupling of narrow-band-gap semiconductor and wide-band-gap semiconductor can solve their inherent drawbacks, simultaneously optimizing the photoabsorption and redox capabilities. In this work, a series of BiOI/Bi2O2[BO2(OH)] heterojunction photocatalysts were synthesized by an in-situ precipitation method. The crystal structure, morphology and surface chemical composition were analyzed to confirm the heterojunction formation. BiOI/Bi2O2[BO2(OH)] heterojunctions show increased specific surface area, which can provide more absorptive and catalytic sites for pollutants. Particularly, the recombination of photogenerated electrons and holes in BiOI/Bi2O2[BO2(OH)] was severely inhibited. Compared to the pristine BiOI and Bi2O2[BO2(OH)], the BiOI/Bi2O2[BO2(OH)] heterojunctions demonstrated substantially enhanced visible-light driven photocatalytic activity for degradation of various contaminants, including methyl orange, methylene blue and tetracycline hydrochloride. The superoxide radicals (O2−) and holes (h+) were determined as the main active species and played crucial role in the photodegradation process, which also verified the formation of type II heterojunction between BiOI and Bi2O2[BO2(OH)]. This work provides an efficient heterojunction photocatalyst for environmental remediation.

A dual strategy to construct flowerlike S-scheme BiOBr/BiOAc1−xBrx heterojunction with enhanced visible-light photocatalytic activity

For broad-band-gap semiconductors like BiO(CH3COO) (denoted as BiOAc), constructing heterojunctions with a narrow-band-gap semiconductor or forming solid solution is an effective strategy to improve visible-light-driven photocatalytic activity. Herein, by combining two strategies, a novel step-scheme (S-scheme) heterojunction BiOBr/BiO(CH3COO)1−xBrx (denoted as BiOBr/BiOAc1−xBrx) was synthesized via a facile co-precipitation method at room temperature. The as-prepared BiOBr/BiOAc1−xBrx with feeding molar ratio of Br/Bi at 0.8 exhibited outstanding visible-light photocatalytic activity for tetracycline (TC) and rhodamine B (RhB) degradation, with degradation efficiency of 99.2% and 99.4%, respectively, which was higher than those of BiOAc (17.3% and 34.8%), BiOBr (57.2% and 62.7%), solid solution BiOAc1−xBrx(x = 0.4) (68.6% and 68.2%) and heterojunction BiOBr/BiOAc (69.9% and 88.1%). The enhanced photocatalytic activity could be attributed to two main aspects. Firstly, the formation of the solid solution BiOAc1−xBrx could not only enlarge visible light response of BiOAc, but also successfully transform type-I heterojunction of BiOBr/BiOAc to typical S-scheme heterojunction of BiOBr/BiOAc1−xBrx, which thus prolong the lifetime of charge carriers with stronger redox ability. Secondly, by adding urea to the reaction system as a morphology modifier, uniform ultrathin nanosheet-based flowerlike BiOAc was obtained, and more importantly, the heterojunction BiOBr/BiOAc1−xBrx inherited the flowerlike contour of BiOAc and thus improved the dispersion, which benefit to the transfer of carriers at the interfaces and onto the surface of nanoparticles. In addition, the as-prepared S-scheme heterojunction also possessed desirable photodegradation efficiency for TC and RhB in real wastewater or in the presence of some electrolytes. This study provides a simply and energy-saving strategy for simultaneously optimizing energy band structures and microstructure to highly efficient heterojunction photocatalysts.

Fabrication of Bi2WO6/In2O3 photocatalysts with efficient photocatalytic performance for the degradation of organic pollutants: Insight into the role of oxygen vacancy and heterojunction

Photocatalysis is an attractive and green strategy for organic pollutant removal. The development of alternative and effective photocatalysts has attracted great attention. Herein, we rationally engineer an alternative rich-oxygen vacancies (OVs) Bi2WO6/In2O3 composite photocatalyst via integrating the calcination and hydrothermal method for removing organic dyes (rhodamine B). Thanks to the synergistic effect of OVs and heterojunction structure, the 80 wt% Bi2WO6/In2O3 (BiIn80) displays enhanced photocatalytic degradation effect. The degradation rate of BiIn80 is up to 97.3% under light irradiation within 120 min and the reaction rate constant k value (0.03221 min−1) is about 15-fold and 4.17-fold as high as those of In2O3 (0.00203 min−1) and Bi2WO6 (0.00772 min−1), respectively. The heterostructure of Bi2WO6/In2O3 can extend the lifespan of the photogenerated charge carriers. Moreover, the density functional theory (DFT) calculations reveal that the OVs in Bi2WO6/In2O3 can boost visible light absorbability by decreasing band gap value and serve as the extra electron transfer channels to enhance the separation efficiency of photogenerated electron-hole pairs. This study not only provides an alternative route for fabricating highly efficient heterojunction photocatalysts, but also obtains better understanding of the synergistic effect of OVs and heterojunction on enhancing the photocatalytic performance.

Plasmon Ag nanoparticle/Bi2S3 ultrathin nanobelt/oxygen-doped flower-like MoS2 nanosphere ternary heterojunctions for promoting charge separation and enhancing solar-driven photothermal and photocatalytic performances

Plasmon Ag nanoparticle/Bi2S3 ultrathin nanobelt/oxygen-doped flower-like MoS2 nanosphere ternary heterojunction photocatalysts are fabricated via hydrothermal and photoreduction strategies. The introduction of Ag nanoparticles and defective MoS2 and the formation of heterojunctions can induce localized surface plasmon resonance and promote charge separation, respectively, which can extend the photoresponse to the visible light and near-infrared regions and obviously enhance the photothermal and photocatalytic performances. The ternary heterojunction photocatalysts show that the photocatalytic degradation ratio of 2,4-dichlorophenol reaches 99.2% under visible light irradiation. In addition, the photocatalytic hydrogen evolution rate reaches 526.3 μmol h−1 g−1, which is several times higher than that of pristine MoS2 and Bi2S3. This study offers a new strategy for designing other highly efficient heterojunction photocatalysts. In addition, these ternary heterojunctions show high stability, which is favorable for practical applications in the environmental and energy fields.

In-situ growing Bi/BiOCl microspheres on Ti3C2 nanosheets for upgrading visible-light-driven photocatalytic activity

Here, we are reporting a new visible-light-driven composite photocatalyst Ti3C2-Bi/BiOCl which builts from Ti3C2 nanosheets and Bi/BiOCl microspheres. It exhibits a higher photocatalytic performance than BiOCl and Bi/BiOCl in degrading antibiotic ciprofloxacin (CIP) under visible light illumination. Such an improved activity for Ti3C2-Bi/BiOCl can be attributed to the introduction of Ti3C2 and Bi. The Bi and Ti3C2 not only significantly broaden the light adsorption of Bi/BiOCl in visible-light region, but also can be served as an excellent “electron trap” for boosting the separation and transfer of photogenerated electrons/holes in Ti3C2-Bi/BiOCl because of its favorable electrical conductivity. Moreover, Ti3C2-Bi/BiOCl shows an well reusability in the five cycles of CIP degradation. This work not only provides a new efficient heterojunction photocatalyst for pollutant abatement in water, but also gives some further insights in constructing multi-component photocatalysts that can work under visible light.

Gas exfoliation of graphitic carbon nitride to improve the photocatalytic hydrogen evolution of metal-free 2D/2D g-C3N4/graphdiyne heterojunction

Abstract Metal-free photocatalysts have received increasing attention as nonmetal elements are abundant in the earth and friendly to the environment. Graphitic carbon nitride (g-C3N4) as a typical two-dimensional (2D) metal-free photocatalysts for water splitting has attracted increasing interest due to its economic production and environmentally friend features. However, the high photocarriers recombination rate constraint its catalytic activity. Combining the single- or few-layered g-C3N4 nanosheets with other 2D functional materials to form efficient metal-free heterojunction photocatalysts is one of the effective strategies to improve the photocarriers separation. Herein, we introduce a simple and efficient method to scalable preparation few-layered g-C3N4 nanosheets using gas exfoliation of bulk g-C3N4 in liquid nitrogen. Then we introduce the g-C3N4 nanosheets into construct a 2D/2D heterojunction of g-C3N4/graphdiyne by π-π interaction, where graphdiyne (GDY) as a new 2D carbon allotrope, has excellent holes transfer nature. We find that the 2D/2D g-C3N4/GDY photocatalyst with 1% GDY is the optimum condition, with the highest H2 evolution rate of 454.28 μmol h−1. The superior photocatalytic performance may be attributed to the excellent photocarriers separation in g-C3N4 under the built-in field, where GDY can rapid transport holes from g-C3N4 to the sacrificial agents.

Hematite microcube decorated TiO2 nanorods as heterojunction photocatalyst with in-situ carbon doping derived from polysaccharides bio-templates hydrothermal carbonization

The novel in-situ formation of a heterojunction photocatalyst consisting of C-doped TiO2 nanorods decorated on the surface of C-doped α-Fe2O3 microcubes was successfully achieved using a one-pot hydrothermal carbonization synthesis. In this work, the treated kapok fibers (t-KF) used as a polysaccharide bio-template provided a dual function for crystal growth control and in-situ carbon doping of the heterojunction photocatalyst. It was found that the α-Fe2O3 precursor concentration plays an essential role in the unique and well-developed C-doped TiO2/α-Fe2O3 heterojunction formation. Assessment of photocatalytic activity of all samples indicated that the sample prepared with 0.25 M of α-Fe2O3 precursor concentration (BT-TF-0.25) exhibited the most efficient bisphenol A photodegradation in aqueous solution. The highest photocatalytic activity of BT-TF-0.25 under simulated solar irradiation was mainly associated with C-doping and favorable heterojunction formation between C-doped TiO2 and C-doped α-Fe2O3. Excellent charge carrier and separation were confirmed from the photocurrent response and photoluminescence spectroscopy analysis. Overall, this study is expected to contribute to the development of more efficient visible light active heterojunction photocatalyst systems, as well as demonstrating the versatility of polysaccharide materials as a green and low-cost bio-templates.

Zn defect-mediated Z-scheme electron-hole separation in AgIn5S8/ZnS heterojunction for enhanced visible-light photocatalytic hydrogen evolution

Exploring high-efficiency Z-scheme heterojunction photocatalyst has been regarded as an effective approach for promoting photocatalytic hydrogen production efficiency. In this study, a novel direct Z-scheme heterojunction composed of AgIn5S8 (denoted as AIS) and Zn-defective ZnS (denoted as D-ZnS) was fabricated via two-step hydrothermal method. The AIS/D-ZnS heterojunction exhibited improved visible light harvesting capability, prolonged charge lifetime and promoted charge separation efficiency, thus contributing to the remarkably enhanced photocatalytic activity as well as stability. The photocatalytic H2 evolution rate of the optimized (0.10:1)AIS/D-ZnS reached 932.76 μmol·h−1 g−1, which was 12 times higher than that of bare D-ZnS (75.13 μmol·h−1 g−1) under visible light irradiation, and an optimal apparent quantum yield of 3.7% was achieved at λ = 420 nm. TEM, XPS, EPR and PL results confirmed the appropriate concentration of Zn defects is conducive to the separation of photogenerated carriers. DMPO-EPR and PL probe experiments for determining O2− and OH active radicals further proved that the transfer and separation of electrons and holes followed Z-scheme mechanism. This work not only presents an alternative strategy for the construction of highly efficient Z-scheme heterojunction photocatalysts, but also provides new insights into the role of defects in mediating the separation and migration of charge carriers.

Well-organized CN-M/CN-U/Pt-TiO2 ternary heterojunction design for boosting photocatalytic H2 production via electronic continuous and directional transmission

Developing highly efficient heterojunction photocatalysts, especially ternary heterojunctions, is a promising strategy to enhance hydrogen (H2) production activity in the photocatalytic process. The compatibility of components and the matching of electronic structure are main challenges in constructing novel photocatalytic activity ternary heterojunctions which include sufficient light absorption, controlled electronic transmission, and high electron utilization efficiency. In this research, the electronic structure of carbon nitride (CN) was regulated continuously by selecting different nitrogen-rich precursors and changing calcination methods, and then CN/CN isotype heterojunctions were constructed to improve the compatibility of components. Next the CN/CN isotype heterojunctions were composited with Pt–TiO2 to design and construct different models of ternary heterojunctions successfully. The different effects of components alignment, band structure and light absorption on photoelectrical and photocatalytic activities were studied systematically in ternary heterojunctions. Among them, the efficient melamine-derived carbon nitride (CN-M)/urea-derived carbon nitride (CN-U)/Pt-TiO2 (CN-M/CN-U/Pt-TiO2) ternary heterojunction has outstanding photocatalytic activity in which the H2 production rate reaches a maximum of approximately 1735 μmol h−1 g−1 using triethanolamine (TEOA) as the sacrificial reagent under visible light irradiation. The H2 production rate is about 4.9 times that of the pure CN-U component, 2.2 times that of the CN-M/CN-U isotype heterojunction and 3.5 times that of the CN-U/Pt-TiO2 binary heterojunction. By means of high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), fluorescence emission spectra, photoelectrochemical and other measurements, the outstanding performance attributed to the well compatible and composited sequence of components, rational energy level alignment and favorable band offset. It is confirmed to result in sufficient light absorption, high efficiency of photo-induced charge separation, and efficient electronic continuous and directional transmission (prolonging the electron lifetime).The study took advantage of the controllability of the electron structure in CN photocatalyst, and provides a facile approach to designing highly efficient visible light responding CN-based ternary heterojunctions for multi-functional applications in the photocatalytic research field.

Hierarchical ZnIn2S4: A promising cocatalyst to boost visible-light-driven photocatalytic hydrogen evolution of In(OH)3

Efficient separation of electrons and holes, associated with the reduction and oxidation, is of great importance in a photocatalytic reaction. 3D hierarchical core-shell-like ZnIn2S4@In(OH)3 microspheres have been fabricated by a facile hydrothermal method via controlling the sulfur source. The marigold-like spherical ZnIn2S4 induced the in situ growth of cubic In(OH)3 nanosheets as the outer shell, which efficiently transferred the photogenerated electrons and achieved efficient charge separation efficiency for highly photocatalytic H2 production. Moreover, the intimate interfacial contact between ZnIn2S4 core and In(OH)3 shell offered rectified charge transfer directions, which further boosted the charge separation. In consequence, the photocatalytic H2 evolution under visible light irradiation was achieved on wide-gap In(OH)3 owing to ZnIn2S4 as a cocatalyst, and a prominent photocatalytic H2 production of 2088 μmol g−1 was obtained on core-shell-like ZnIn2S4@In(OH)3 structure with an apparent quantum efficiency of 1.45% (400 nm), which was nearly 2-folds higher of H2 production rate than the pristine ZnIn2S4. This work provides a prototype material for high efficiency of hydrogen evolution, and gives a new insight for the development of efficient heterojunction photocatalysts.

Synthesis and enhanced visible light-induced photocatalytic activity of a hierarchical porous biomorphic N/Zn–TiO2@NH2-MIL-125 photocatalyst

Heterojunction is considered as very promising material for various applications in photocatalysis. Herein, an efficient heterojunction photocatalyst N/Zn–TiO2@NH2-MIL-125 was successfully synthesized for photo-degradation organic oxidation by biological-templated method. The electron–hole pairs can be separated in space more efficiently because of heterojunction structure. Systematical analyses of spectroscopy and microscopy measurements revealed that N/Zn–TiO2@NH2-MIL-125 heterojunction materials exhibited hierarchical porous structure with high surface area of 366.02 m2 g−1 and outstanding optical properties. Photocatalytic activity was investigated by degradating of rhodamine B (1000 µM) under visible-light irradiation. The N/Zn–TiO2@NH2-MIL-125 showed enhanced photocatalytic activity for RhB degradation, which is respectively about 1.81 and 1.97 times higher than that of the pristine N/Zn–TiO2 and NH2-MIL-125. Various advanced spectroscopic characterizations were applied including photoluminescence, Mott–Schottky curves and electrochemical impedance spectroscopy. A possible mechanism of enhanced photocatalytic oxidation activity for N/Zn–TiO2@NH2-MIL-125 composite under visible light irradiation was discussed.

The effect of halogen on BiOX (X = Cl, Br, I)/Bi2WO6 heterojunction for visible-light-driven photocatalytic benzyl alcohol selective oxidation

We developed a simple X−-assisted (X = Cl, Br, I) one-pot hydrothermal reaction to successfully synthesize a series of BiOX/Bi2WO6 heterojunction. The effect of different halogens and their addition amount on the photocatalytic performance of BiOX/Bi2WO6 composites was investigated using benzyl alcohol selective oxidation under visible-light irradiation. All BiOX could enhance the photocatalytic activity of Bi2WO6, but the BiOBr was the optimum for the maximum improvement of Bi2WO6. The match of energy band structure between BiOX and Bi2WO6 resulted in the highly efficient separation of photogenerated charges, which was mainly attributed to their fundamental distinction of the photocatalytic activity. This work clarified the essential distinction in photocatalytic performance of the different halogen of BiOX/Bi2WO6 heterojunction, and also provided guidance for the construction of efficient heterojunction photocatalysts.

Facile Synthesis of Ag/AgCl Grafted AgBi(MoO4)2 with Enhanced Photocatalytic Performance Under Visible Light

Silver nanoparticles (NPs) and related semiconductors are a family of very important and widely applied photocatalysts. However, the preparation of high stability and activity of this photocatalyst is still a challenge. In this work, we report a stable Ag/AgCl/AgBi(MoO[Formula: see text] heterojunction photocatalyst fabricated via a simple in situ anion-exchange reaction followed by the photoreduction treatment. In the treatment of tetracycline (TC) wastewater under visible light, the AC-0.4 sample (prepared with 0.4[Formula: see text]mmol KCl) exhibits the significantly improved activity (degradation ratio, DR of 71.3%) compared with the pristine AgBi(MoO[Formula: see text] (30% DR) and Ag/AgCl sample (synthesized by the photoreduction of AgCl) (37% DR) under identical experimental conditions. This activity promotion is from the fast interfacial electron transfer between the heterojunction phases of AgCl/AgBi(MoO[Formula: see text] and the SPR effect of Ag NPs. After five successive recycles, the AC-0.4 sample still maintains good stability and activity for TC degradation, which shows a great potential to be used in practical application. Through the ESR and controlled scavenged experiments, we found the [Formula: see text]OH and [Formula: see text]O[Formula: see text] are the major reactive intermediate species in the TC photodegradation reaction. Our work provides a new insight into the synthesis of stable and high efficient Ag-based heterojunction photocatalysts for the application of wastewater treatment.

Facile synthesis of cerium oxide nanoparticles decorated flower-like bismuth molybdate for enhanced photocatalytic activity toward organic pollutant degradation

One of the great challenges in the field of photocatalysis is to develop novel photocatalysts with excellent solar-light-harvesting capacity and separation efficiency of photo-induced charge. Herein, novel CeO2/Bi2MoO6 heterojunctions were fabricated through in-situ precipitation of CeO2 nanoparticles (size: ∼26 nm) on the surface of flower-like Bi2MoO6 superstructures (diameter: 2.1–3.5 μm) by a simple method. The as-prepared photocatalysts were systematically characterized by a range of techniques. The photocatalytic degradation of rhodamine B (RhB) dye, methyl orange (MO) dye and tetracycline (TC) antibiotic by this novel photocatalyst was investigated under visible-light irradiation. The CeO2/Bi2MoO6 heterojunction with a CeO2/Bi2MoO6 weight ratio of 0.05 (0.05Ce-Bi) exhibited the highest photocatalytic activity with the RhB degradation efficiency of 100% in 75 min, which was considerably higher than those of pristine CeO2 (26.8%) and Bi2MoO6 (80.3%) as well as their physical mixtures (74.8%). The more efficient separation of electron-hole pairs was identified as the primary reason of the enhanced photocatalytic activity. Moreover, the synthesized material maintained satisfactory activity even after 6 recycling runs, indicating its high photocatalytic stability. Therefore, our finding offers a new avenue for development of stable and efficient heterojunction photocatalysts for environmental purification.

Degradation and removal of Ceftriaxone sodium in aquatic environment with Bi2WO6/g-C3N4 photocatalyst

Modern chemistry aims to identify outstanding photocatalytic materials for antibiotic degradation given the overuse and misuse of antibiotics. Herein, highly efficient heterojunction photocatalysts composed of Bi2WO6 nanoflowers (BW) and g-C3N4 nanosheets (CNNs) were successfully synthesized. The Bi2WO6/g-C3N4 (BW/CNNs) were presented for Ceftriaxone sodium degradation in the aquatic environment at low concentrations under visible light irradiation. The 40%-BW/CNNs showed excellent photocatalytic activity, and approximately 94.50% Ceftriaxone sodium was degraded under visible lightirradiation for 120 min. h+ and O2− played major roles compared with ·OH in the photocatalytic process. The degradation mechanism and the intermediate products were proposed to better understand the reaction process. Moreover, the as-prepared photocatalysts were highly stable in recycling photocatalytic experiments. Therefore, the photocatalysts prepared in the study showed outstanding photocatalytic activity and potential applications in inhibiting environmental pollution. In addition, this work provides a new insight for constructing other high-performance, low-cost photocatalysts for wastewater treatment.