Transfer Of Photoinduced Carriers Research Articles

A novel photocatalytic platform based on the newly-constructed ternary composites with a double p-n heterojunction for contaminants degradation and bacteria inactivation

Visible-light-induced photocatalytic technique is regarded as the most promising approach to tackle environmental pollution. Herein, a novel ternary MIL-88B@COF-200@10%PANI composite with a double p-n heterojunction was firstly synthesized through a step-by-step self-assembly strategy. Current results suggested that bimetallic Fe.Co-MIL-88B displayed excellent photocatalytic activity, and its combination with spherical COF-TPA/TPB effectively promoted separation and transfer of photoinduced carriers. Meanwhile, introducing PANI with π-π conjugated structure acted as a “bridge” of the charge transport could further boost carrier mobility and enhance absorption in visible light region. Benefiting from the formation of double p-n heterojunction, the recombination of photogenerated electron-hole pairs was inhibited effectively, thereby improving the photocatalytic activity. More significantly, in comparison with pristine COF-TPA/TPB, Fe.Co-MIL-88B and PANI, the MIL-88B@COF-200@10%PANI composite not only presented excellent degradation ability for various contaminants, but also exhibited superb sterilization effect for E. coli and S. aureus. The OH, O2−, h+ and e− were main active species in the photocatalytic reaction system, which were responsible for pollutant degradation and bacteria inactivation. Furthermore, it was proved by our experiment results that the separation and transfer routes of photogenerated charge carriers followed a traditional type-II heterojunction mechanism. All in all, this study could provide novel insights for preparation and application of highly efficient photocatalyst in future research.

Giant responsivity of a new InGaZnO ultraviolet thin-film phototransistor based on combined dual gate engineering and surface decorated Ag nanoparticles aspects

In this paper, a new InGaZnO (IGZO) thin-film UV Phototransistor (Photo-TFT) based on both dual material gate (DM) and plasmonic Ag nanoparticles (NPs) is proposed, in hope of combining the beauties of both aspects to achieve enhanced photogeneration/collection efficiency. An accurate drain-current model for the investigated device is developed, where a good agreement with the experimental data is achieved. The optical behavior of IGZO thin-film decorated with Ag NPs is analyzed using 3-D FDTD method. Interestingly, a strategic combination between the developed model and Particle Swarm Optimization (PSO) technique is conducted to find out the appropriate DM gate configuration and the best Ag NPs spatial arrangement offering the highest device Figure of Merits (FoMs). It is revealed that the optimized design showcases giant responsivity exceeding 103 A/W and superb detectivity of 6.8 × 1014 Jones, which are far beyond conventional IGZO Photo-TFTs. These improvements are attributed to localized surface plasmon resonance effects (LSPR), leading to enhance the UV-absorbance capability. Moreover, the optimized DM gate generates intense electric-field in the IGZO channel, allowing the efficient separation and transfer of photo-induced carriers. Therefore, promoting enhanced photogeneration/collection efficiency, this innovative strategy based on decorated Ag NPs combined with DM gate engineering provide a sound pathway for designing potential alternative IGZO Photo-TFT for the future optoelectronic technology.

Design of BiOBr nanosheets decorated SiC whisker hybrid structure with enhanced photocatalytic performance

Although BiOBr exhibits unique layer structures and good visible light response features as photocatalysts, it has been limited by low surface area and poor carries separation. Herein, a simple hydrothermal approach is reported for planting 2D BiOBr nanosheets on 1D SiC whiskers to obtain the binary hybrid structure. By further controlling the hydrothermal temperature, the loading content of BiOBr on SiC whiskers surface, the band structure of BiOBr/SiCw hybrids could be finely tuned to optimize photodegradation activity. Results demonstrate that the construction of BiOBr/SiC hybrid structure not only increases surface area to provide more activity sites, but also improves photo-induced carriers transfer for strengthening the separation of the photo-induced carrier, which favors photodegradation activity. More importantly, the electron spin resonance and capture experiment reveals that holes are the main species responsible for the oxidation of contaminants. Benefited from the above characteristics, the optimized BS160 exhibits efficient photodegradation ability, where 97% Rhodamine B (RhB) is eliminated after 15 min and 60% tetracycline hydrochloride is degraded after 60 min under visible light irradiation, respectively. Moreover, the optimized BS160 also displays excellent photocatalytic stability after 5 reusability cycles. This work paves a new route for the development of photocatalysts based on BiOBr.

CQDs decorated oxygen vacancy-rich CeO2/BiOCl heterojunctions for promoted visible light photoactivity towards chromium (Ⅵ) reduction and rhodamine B degradation

Engineering a heterojunction with high photoactivity and better exciton separation in photocatalyst is a promising target for environmental purification. In this context, we fabricated CQDs decorated double-shell CeO2 hollow spheres(D-CeO2)/BiOCl heterojunction (D-CeO2: CQDs/BiOCl) composite by a simple method and scrutinized it photocatalytic performance toward chromium (Ⅵ) reduction and rhodamine B degradation. The resultant D-CeO2: CQDs/BiOCl composite is validated much more active under visible light irradiation with the high rhodamine B degradation rate of 0.12min−1 which is about 3 and 255 times, meanwhile, chromium (Ⅵ) reduction rate of 0.015 min−1 which is about 6 and 32 times higher than the neat BiOCl and D-CeO2, respectively. The interfacial domain of D-CeO2/BiOCl decorated with CQDs for efficient photoinduced charge carriers transfer and separation are the point to attractive photocatalytic performance which combines the double-shell hollow sphere morphology with highly efficient light harvesting, rich OVs for the charge carriers fast separation and accelerated charge transfer after the CQDs participating.

W18O49 Frameworks Decorated with Graphitic Carbon Nitride Quantum Dots for Photocatalytic Hydrogen Production

Quantum dots (QDs) have exhibited remarkable advantages for photocatalytic H2 evolution. Unfortunately, despite their unique quantum size effects and abundant catalytic active sites, many applications of QDs have been hindered in that they are prone to aggregation and easy to leach off from the substrate. Therefore, it is highly desirable to fabricate a special nanostructure with confinement effects to conquer their intrinsic drawbacks. Herein, we present a direct g-C3N4–x/W18O49 Z-scheme nanocomposite for enhanced photocatalytic H2 production. This system is composed of a W18O49 framework with several microporous slits and g-C3N4 QDs with a rich nitrogen vacancy. These several microporous slits can fix QDs and avoid their aggregation. Besides, the microporous slit surface can be functionalized by adjusting the pH value, thus ensuring intimate contact between W18O49 framework and g-C3N4–x QDs. The unique Z-scheme confinement structure facilitates photoinduced carrier transfer and improves the photocatalytic H2 production performance. The g-C3N4–x/W18O49 nanocomposite exhibits an exceedingly high H2 evolution rate and super stability because of the confinement structure and effective charge channel. This study provides a strategy to design the high-efficiency catalysts for solar H2 production.

Biomimetic synthesis of 2D/2D mixed graphitic carbon nitride /carbonized polydopamine nanosheets with excellent photocatalytic performance

In recent years, exploring efficacious visible-light photocatalysis has been one of core concerns owing to potential applications for energy utilization and environmental remediation. Among all nanostructured photocatalysts, the nano-hierarchical material composed of two-dimensional (2D) nanosheets is terrific owing to abundant 2D coupling interfaces that can decrease the diffusion distance of photogenerated carriers and facilitate the interfacial electronic transfer. Herein, utilizing the biomimetic adhesion, 2D/2D graphitic carbon nitride nanosheet/carbonized polydopamine (CNNS/CPDA) nanocomposites were fabricated via the dopamine (DA) self-polymerization on the surface of graphitic carbon nitride (GCN) followed by carbonization and delamination. Wherein CPDA acts a crucial role for the reinforcement of photocatalytic degradation activity in CNNS/CPDA nanocomposites. On the one hand, CPDA has strong adsorption capacity that can accelerate the adsorption and degradation of rhodamine B (RhB) molecules. On the other hand, as one of carbon materials, CPDA has high conductivity and contacts with CNNS tightly, which is conducive to the transfer of photo-induced carriers. Hence, for the optimal CNNS/CPDA nanocomposite (CNNS/CPDA-2), the RhB degradation rate (0.0466 min−1) is 5.1 times as high as that of pure GCN. This kind of 2D/2D nanocomposites based on one-pot biomimetic strategy may hold significant promise in practical applications of water treatment.

Metal-free plasmonic boron phosphide/graphitic carbon nitride with core-shell structure photocatalysts for overall water splitting

In this work, we report a novel metal-free plasmonic boron phosphide/graphitic carbon nitride (BP@g-C3N4) catalyst for photocatalytic overall water splitting. The BP@C3N4 catalyst exhibits broadened spectral adsorption in UV–vis to NIR region and shows the activity for hydrogen evolution even under 730 nm illumination, which is close to NIR region of solar irradiation. The highest H2 production rate reaches 31.5 μmol g−1 h−1 under visible light irradiation, which is 34.3 and 112.6 times higher than corresponding data of Pt/g-C3N4 and g-C3N4 catalysts respectively without noble metal loading. The finite element frequency-domain simulations indicate that the significantly improved photocatalytic water splitting performance is due to the BP plasmon resonance leading to effectively photo-induced carrier separation and transfer, which is crucially for solar energy harvesting and utilization. The metal-free earth-abundant plasmonic BP@g-C3N4 can catalyze photocatalytic overall water splitting by the plasmonic effect under visible light and near infrared irradiation efficiently.

Ni(OH)2 modified Mn0.5Cd0.5S with efficient photocatalytic H2 evolution activity under visible-light

Developing high-efficiency photocatalysts for water decomposition is one of the major challenges in converting solar energy to chemical energy. In this paper, Ni(OH)2 modified Mn0.5Cd0.5S solid solution without the use of precious metals is successfully synthesized via hydrothermal method followed by precipitation, the photocatalytic activity for hydrogen evolution and stability of composite samples present significant improvement with respect to the pristine Mn0.5Cd0.5S. These improvements are attributed to that Mn0.5Cd0.5S CB potential (−0.7 V vs. NHE) is more negative than the potential of Ni2+/Ni (−0.23 V vs. NHE), which promotes the transfer of photo-generated electrons from Mn0.5Cd0.5S CB to Ni(OH)2 for H2 production as well as partial reduction of Ni2+ to Ni0, leaving VB holes to oxidize the sacrificial reagents. The metal Ni atoms with conductivity and Ni(OH)2 nanoparticles not only boost the segregation and transfer of photo-induced carriers but also act as water-reduction promoter, thereby promoting the photocatalytic activity for hydrogen release. A novel visible light responsive MnxCd1-xS-based photocatalytic material promising for practical applications is provided in this subject.

Boosting Visible‐Light Photocatalytic Performance for CO2 Reduction via Hydroxylated Graphene Quantum Dots Sensitized MIL‐101(Fe)

AbstractHerein, a one‐step solvothermal method that shows incorporation of the graphene quantum dots (GQDs) on Fe‐based metal organic frameworks (MOFs) [MIL‐101(Fe)] to form GQD/MIL‐101(Fe) (G/M101) composites is reported. MIL‐101(Fe) with the sensitization of GQDs could significantly improve the photocatalytic reduction efficiency of CO2 to generate CO. The prepared composites exhibit excellent optical properties and the photocatalytic activity of G/M101 composites is relevant to GQDs ratio. The CO production rate over G/M101‐5% (224.71 µmol h−1 g−1) is 5 times higher than that of MIL‐101(Fe) (46.20 µmol h−1 g−1). The promising photocatalytic activity of G/M101‐5% strongly depends on the beneficial separation and transfer of photoinduced carriers via a charge migration between GQDs and MIL‐101(Fe). The microstructures and interfacial structures of the G/M101‐5% composite demonstrate that GQDs are closely loaded on the surface of MIL‐101 (Fe), and thus favors to the photoreduction according to their sp2 bonding. This work may figure a new way for the synthesis of photocatalysts for the application on carbon stabilization.

Piezo-enhanced photodegradation of organic pollutants on Ag3PO4/ZnO nanowires using visible light and ultrasonic

An imperative challenge emerged in the area of photocatalysis is the recombination of photoinduced electron–hole, which severely restricts the photodegradation efficiency of organic pollutants. This study proposes a piezoelectric Ag3PO4/ZnO nanowire with enhanced degradation performance of organic pollutants. The proposed nanowire can generate a piezoelectric effect under ultrasonic vibration to promote the separation and transfer of photoinduced carriers. The Ag3PO4/ZnO nanowires are fabricated by a simple two-step approach, and its structure and properties are tested by various methods. Results show that the Ag3PO4 nanoparticles are attached on the surface of the ZnO nanowires, which endow the photocatalyst with enhanced absorption in the visible-light region. Photochemical and photoluminescence studies show that Ag3PO4/ZnO nanowires have good electron–hole pairs separation. Under light and ultrasonic radiation, Ag3PO4/ZnO nanowires (APZ-3) on a stainless steel mesh (3.0 × 3.0 cm, ~30 mg) show an optimum piezo-photocatalytic performance for MB with 98.16% degradation rate in 30 min. The reaction rate constants of piezo-photocatalytic Ag3PO4/ZnO nanowires (APZ-3) are 4.13 times of those conventional photocatalytic ZnO nanowires. In addition, the as-prepared sample is applied to the treatment of antibiotics in aqueous solutions, such as ciprofloxacin, norfloxacin, and ofloxacin, and achieves good degradation efficiency. The enhanced photocatalytic performance can be owed to the formation of the p–n heterojunction at the Ag3PO4/ZnO interface and the generation of the piezoelectric effect of ZnO nanowires in the degradation process. The results also demonstrate an economical way for practical applications in the degradation of organic pollutants at the industrial level.

Extensive solar light harvesting by integrating UPCL C-dots with Sn2Ta2O7/SnO2: Highly efficient photocatalytic degradation toward amoxicillin

The carbon dots (C-dots) mediated Sn2Ta2O7/SnO2 heterostructures with spongy structure were successfully assembled by simple hydrothermal route. The photocatalytic removal efficiency of amoxicillin (AMX, 20 mg L−1) over C-dots/Sn2Ta2O7/SnO2 was estimated to reach up 88.3% within 120 min simulated solar light irradiating. Meanwhile, the HPLC-MS/MS analysis and density functional theory (DFT) computation were examined to clarify the photo-degradation pathway of AMX. The mechanism investigation proposed that with the modification of C-dots, the photocatalysts improves the utilization of solar energy by harvesting the long wavelength solar light due to their unique up-converted photoluminescence (UCPL). In addition, the porous spongy structure and plenty of tiny C-dots promote the ability of adsorption by enlarged specific surface area. Furthermore, the C-dots mediated Z-type heterojunction of Sn2Ta2O7/SnO2 facilitates the efficient separation and transfer of photo-induced carriers. Our work affords a promising approach for the design of the high-efficient photocatalysts to remedy poisonous antibiotics in aqueous environment.

Ag as Cocatalyst and Electron-Hole Medium in CeO2 QDs/Ag/Ag2Se Z-scheme Heterojunction Enhanced the Photo-Electrocatalytic Properties of the Photoelectrode.

A recyclable photoelectrode with high degradation capability for organic pollutants is crucial for environmental protection and, in this work, a novel CeO2 quantum dot (QDs)/Ag2Se Z-scheme photoelectrode boasting increased visible light absorption and fast separation and transfer of photo-induced carriers is prepared and demonstrated. A higher voltage increases the photocurrent and 95.8% of tetracycline (TC) is degraded by 10% CeO2 QDs/Ag2Se in 75 minutes. The degradation rate is superior to that achieved by photocatalysis (92.3% of TC in 90 min) or electrocatalysis (27.7% of TC in 90 min). Oxygen vacancies on the CeO2 QDs advance the separation and transfer of photogenerated carriers at the interfacial region. Free radical capture tests demonstrate that •O2−, •OH, and h+ are the principal active substances and, by also considering the bandgaps of CeO2 QDs and Ag2Se, the photocatalytic mechanism of CeO2 QDs/Ag2Se abides by the Z-scheme rather than the traditional heterojunction scheme. A small amount of metallic Ag formed in the photocatalysis process can form a high-speed charge transfer nano channel, which can greatly inhibit the photogenerated carrier recombination, improve the photocatalytic performance, and help form a steady Z-scheme photocatalysis system. This study would lay a foundation for the design of a Z-scheme solar photocatalytic system.

Well-organized assembly of ZnO hollow cages and their derived Ag/ZnO composites with enhanced photocatalytic property

Unique and controllable well-organized ZnO hollow cages were formed for the first time by smart assembly using novel combination of L-TA and EA, which can produce a strong synergistic effect in hydrothermal process. Meanwhile, the conformation of L-TA and D-TA shows that these ZnO cages have special spatial assembly order. The photocatalytic activity of Ag/ZnO is remarkably larger than that of pristine ZnO (S2) under UV or simulated sunlight irradiation. The MB rate constant k values of Ag/ZnO composites are larger than those of P25 under UV light illumination. Under simulated sunlight irradiation, S2-10% Ag/ZnO degrades 80% of RhB in 135 min. The PL, photocurrent and EIS results indicate enhanced photocatalytic performance due to the interfacial formation between Ag and ZnO, which facilitates the separation and transfer of photoinduced carriers and enhances the photocatalytic activity of Ag/ZnO composites. This work provided a new way to design and construct well-organized ZnO hollow cages and their derived Ag/ZnO photocatalysts.

Room temperature synthesis of BiOBr1-x I x thin films with tunable structure and conductivity type for enhanced photoelectric performance.

The surface states of semiconductors determine the semiconductor type. Although BiOCI, BiOBr and BiOI all belong to the bismuth oxyhalide semiconductor family and have similar crystal structures and electronic structures, they exhibit different conductivity types due to their respective surface states. In this paper, a modified successive ionic layer adsorption and reaction (SILAR) method was developed to fabricate I-doped BiOBr1−xIx nanosheet array films on FTO substrates at room temperature for the first time. Interestingly, the properties of p-type BiOBr were changed by doping an appropriate amount of iodine into a BiOBr film to form an n-type BiOBr1−xIx thin film. The I-doped BiOBr1−xIx (x = 0.2, 0.4, 0.5) nanosheet arrays had a perfect single-crystal structure, and the dominant growth plane was (110). A higher doping amount of I led to a darker colour of the BiOBr1−xIx film and a redshift of the absorption wavelength; consequently, the bandgap value changed from 2.80 eV to 1.85 eV. The highest short-circuit current and open-circuit voltage of the solar cell based on BiOBr0.5I0.5 film could reach 1.73 mA cm−2 and 0.55 V, which was considered to be attributed to the effective light absorbance, long photogenerated charge lifetime and sufficient charge separation in the BiOBr0.5I0.5 film.

Highly transparent phototransistor based on quantum-dots and ZnO bilayers for optical logic gate operation in visible-light.

Highly transparent optical logic circuits operated with visible light signals are fabricated using phototransistors with a heterostructure comprised of an oxide semiconductor (ZnO) with a wide bandgap and quantum dots (CdSe/ZnS QDs) with a small bandgap. ZnO serves as a highly transparent active channel, while the QDs absorb visible light and generate photoexcited charge carriers. The induced charge carriers can then be injected into the ZnO conduction band from the QD conduction band, which enables current to flow to activate the phototransistor. The photoexcited charge transfer mechanism is investigated using time-resolved photoluminescence spectroscopy, scanning Kelvin probe microscopy, and ultraviolet photoelectron spectroscopy. Measurements show that carriers in the QD conduction band can transfer to the ZnO conduction band under visible light illumination due to a change in the Fermi energy level. Moreover, the barrier for electron injection into the ZnO conduction band from the QD conduction band is low enough to allow photocurrent generation in the QDs/ZnO phototransistor. Highly transparent NOT, NOR, and NAND optical logic circuits are fabricated using the QDs/ZnO heterostructure and transparent indium tin oxide electrodes. This work provides a means of developing highly transparent optical logic circuits that can operate under illumination with low-energy photons such as those found in visible light.

A Highly Efficient Composite Catalyst Constructed From NH2-MIL-125(Ti) and Reduced Graphene Oxide for CO2 Photoreduction.

Substantial consumption of fossil fuels causes an increase in CO2 emissions and intensifies global pollution problems, such as the greenhouse effect. Recently, a new type of ultra-low-density porous material, metal-organic frameworks (MOFs), has been developed for the photocatalytic conversion of CO2. Herein, a composite photocatalytic catalyst based on NH2-MIL-125(Ti) and reduced graphene oxide (rGO@NH2-MIL-125) was fabricated through a facile “one-pot” process. The acquired materials were characterized to obtain their structures, morphologies, and optical information. The experimental results showed that methyl formate (MF) was the predominant reaction product, and rGO@NH2-MIL-125 exhibited the highest yield of 1,116 μmol·g−1·h−1, more than twice that of pure MIL-125. The high photoactivity of rGO@NH2-MIL-125 can be ascribed to the effective spatial separation and transfer of photoinduced carriers, largely due to the synergistic effect of amino functionality and rGO incorporation. rGO@NH2-MIL-125 also displayed acceptable repeatability in cyclic runs for CO2 reduction.

Highly efficient Zr-MOF@WO3/graphene oxide photocatalyst: Synthesis, characterization and photodegradation of tetracycline and malathion

In this study, for the first time, a novel MOF based nanocomposite, UiO-66@ WO3/graphene oxide (UiO-66@WG) was synthesized by a solvothermal method and its ability was evaluated for photodegradation of two pollutant models containing aromatic (tetracycline (TC)) and nonaromatic (malathion (MA)). The characterization of nanocomposite was performed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and N2 adsorption–desorption technique. The best efficiencies (84% and 100% for TC and MA respectively) obtained using UiO-66@35WG under 70 min visible light irradiation which is noticeably more efficient when compared with pure UiO-66. This enhancement arises from several aspects containing increase in visible light response, proper matching of conductive and valence bands belong to UiO-66 and WO3 that led to improved separation of electron-hole pair and faster transfer of photoinduced carriers on layers of graphene oxide. The reduced band gap, various functional groups and good availability of active sites also are other positive factors in this design. The total oxygen carbon (TOC) analysis indicated 75%, 83% mineralization efficiency for TC and MA respectively, indicating acceptable decomposition of these pollutants under optimum condition. Furthermore, this nanocomposite shown good reusability after 4 consecutive runs.

Carbon nitride nanoplatelet photocatalysts heterostructured with B-doped carbon nanodots for enhanced photodegradation of organic pollutants

Decorating electron-accepting materials on carbon nitride (C3N4) is a promising strategy to construct heterostructure catalysts for improved photocatalytic abilities. In this study, B-doped carbon-dots (B-C-dots) decorated C3N4 (C3N4/B-C-dots) catalysts were fabricated through the surface deposition. The benefits from integration of B-C-dots and C3N4 are four folds: (i) increasing surface area; (ii) improving visible light absorption; (iii) promoting the transfer of photoinduced carriers; and (iv) reducing the recombination of photoinduced carriers. The optimum photocatalytic activity of B-C-dots/C3N4 for Rhodamine B (Rh B) (or tetracycline hydrochloride (TC)) degradation was about 7.21 (6.56) and 4.80 (4.35) times higher than that of C3N4 and C-dots/C3N4, respectively, exhibiting both remarkable stability and repeatability. Moreover, enhanced photocatalytic activity of C3N4/B-C-dots could also be attributed to the type-II heterojunction formed between C3N4 and B-C-dots caused by B doping.

The BiOCl/diatomite composites for rapid photocatalytic degradation of ciprofloxacin: Efficiency, toxicity evaluation, mechanisms and pathways

The activity and separation performance of nano-structure photocatalyst have always been the focus in the field of environmental pollutant removal. In this work, BiOCl/diatomite composites were successfully fabricated via a simple hydrolysis method, which could meet the above two requirements. The superior performance of composites was explained by using X-ray diffractometer (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results revealed that the tetragonal phase BiOCl and diatomite coexisted in the composites, producing the synergistic effect. The diatomite had the high adsorption and silicon hydroxyl groups while the BiOCl had the exposed (001) facets. Diatomite as a carrier was actually equivalent to a solid dispersant, which could immobilize BiOCl microspheres evenly on its surface and prevent their aggregation, guaranteeing more active sites of BiOCl be exposed and promoting the transfer and separation of photo-induced carriers. The prepared BiOCl/60%D presented 94% removal efficiency for ciprofloxacin (CIP) under simulated solar light within 10 min irradiation, and also presented a 42.9% of total organic carbon (TOC) removal after 240 min. Despite the mineralization of CIP was incomplete, toxicity assessment indicated effective elimination of CIP antibacterial property by BiOCl/60%D in a short time. Moreover, the BiOCl/60%D exhibited good stability and reusability. The formation mechanism of BiOCl/diatomite composites was speculated, meanwhile, the photocatalytic degradation mechanism and pathways of CIP were also deduced by using radicals trapping experiments, electron spin resonance (ESR), high performance liquid chromatography (HPLC) and mass spectrometry (MS). This study provided a simple method of building efficient BiOCl/diatomite composites for fast degradation of CIP in water, which had substantial attraction for application.

Covalently integrated core-shell MOF@COF hybrids as efficient visible-light-driven photocatalysts for selective oxidation of alcohols

Abstract Building a covalently connected structure with accelerated photo-induced electrons and charge-carrier separation between semiconductors could enhance the photocatalytic performance. In this work, we report a facile and novel seed growth method to coat NH2-MIL-125 MOFs with crystalline and porous covalent organic frameworks (COFs) materials and form a range of NH2-MIL-125@TAPB-PDA nanocomposites with different thicknesses of COF shell. The introduction of appropriate content of COF could not only modify the intrinsic electronic and optical properties, but also enhance the photocatalytic activity distinctly. Especially, NH2-MIL-125@TAPB-PDA-3 with COF shell thickness of around 20 nm exhibited the highest yield (94.7%) of benzaldehyde which is approximately 2.5 and 15.5 times as that of parental NH2-MIL-125 and COF, respectively. The promoted photocatalytic performance of hybrid materials was mainly owing to the enhanced photo-induced charge carriers transfer between the MOF and COF through the covalent bond. In addition, a possible mechanism to elucidate the process of photocatalysis was explored. Therefore, this kind of MOF-based photocatalysts possesses great potentials in future green organic synthesis.