Full Spectrum Response Research Articles

Efficient photocatalytic degradation of microplastics by constructing a novel Z-scheme Fe-doped BiO2−x/BiOI heterojunction with full-spectrum response: Mechanistic insights and theory calculations

Recently, microplastics (MPs) have garnered significant attention as a challenging emerging pollutant to address. Here, a full-spectrum light-driven Fe-doping BiO2−x/BiOI (FBI) Z-scheme heterojunction was constructed for efficiently degrading MPs in waters. Compared with BiO2−x, Fe doping BiO2−x, and BiOI, the optimal photocatalyst (40-FBI) can cause deep cracks in the polyethylene terephthalate (PET) within 10 h under the irradiation of full-spectrum light. Meanwhile, FT-IR characterization revealed that the absorption peak intensities of the C-O group, CO group, -CH stretching vibration, and -OH group on the MPs surface gradually increased with degradation time. A series of experiments and theory calculations revealed that the introduction of Fe creates impurity levels, accelerating the separation of photo-generated carriers and reducing the work function of BiO2−x, thereby enhancing the transport of photo-generated carriers between Z-scheme heterojunctions. This study offers a valuable idea for designing an efficient photocatalyst by simultaneously introducing ion doping and constructing heterojunctions for enhancing MPs degradation.

Z-scheme ZnIn2S4/CuxO heterostructure on flexible substrate for efficient photothermal catalytic CO2 reduction

The ZnIn2S4 nanosheets were successfully synthesized on the surface of compacted stainless steel mesh using a simple solvothermal method, and further modified with CuxO nanoparticles to form ZnIn2S4/CuxO heterojunction photocatalyst via a wet chemistry approach. These photocatalysts were then utilized for photothermal catalytic CO2 reduction under full spectrum solar light. The experimental results demonstrated that the deposition of the photocatalyst on the flexible substrate effectively prevented the aggregation of ZnIn2S4 nanosheets. The incorporation of CuxO nanoparticles enhanced the specific surface area of the photocatalyst, and created a Z-scheme heterojunction with ZnIn2S4 to improve the utilization efficiency of photogenerated electrons. It was noteworthy that the dark red CuxO exhibited a full spectrum response and excellent photothermal effect, thereby facilitating carrier migration and reducing CO2 catalytic reaction barriers. Consequently, the optimized ZnIn2S4/CuxO exhibited significantly enhanced CO2 to CO yield of 1515.8 μmol m-2h−1 and CH4 yield of 1579.4 μmol m-2h−1, which was about 7.5 and 7.6 times higher than those achieved by pure ZnIn2S4, respectively. Furthermore, this study provided detailed insights into the mechanism of photocatalytic CO2 reduction over composite material as well as valuable guidance for designing immobilized photocatalysts with high activity for CO2 reduction.

Identification of the Asymmetric Transmission Error and Gear Mesh Dynamic Parameters using Full-Spectrum Responses in a Geared-Rotor System

A dominant source of vibration in geared-rotor systems are the gear mesh fault parameters. They include the asymmetric transmission error, phases of transmission error, the gear mesh stiffness, the gear mesh damping and the gear runouts. The present work deals with the experimental identification of aforementioned parameters. A mathematical model of geared-rotor system has been developed using Lagrangian dynamics. Equations of motion are transformed into frequency domain using the full-spectrum response analysis. These transformed equations are used to develop an identification algorithm based on least-squares fit to estimate the transmission error and gear mesh dynamic parameters. The system identification algorithm is initially verified using numerical simulations. The robustness of the algorithm is checked by introducing white Gaussian noise in the simulated responses. A geared-rotor experimental rig was developed and used to measure responses at gear locations in two orthogonal directions. Measured responses are transformed in frequency domain using the full-spectrum analysis and used in the present novel identification algorithm to identify the gear parameters. The identified parameters are validated by comparing the numerically generated full-spectrum response using experimentally estimated parameters and that from the experimental rig. Conflict of Interest Statement The authors declare no conflicts of interest.

Enhanced photocatalytic degradation of organic pollutants in actual sewage water with a full-spectrum-responsive NaYF4:Yb,Tm@NaYF4:Yb,Nd@TiO2@g-C3N4 nanoheterojunction photocatalyst

Full spectrum-excitation photocatalysis is promising for the environmentally friendly treatment of actual sewage with sunlight. High-efficiency, stable NaYF4:Yb,Tm@NaYF4:Yb,Nd@TiO2@g-C3N4 (UPTC) nanoheterojunction photocatalysts were fabricated via facile chemical synthesis. Nanophotocatalyst characterization revealed good crystallinity, strong composite formation, and a high separation rate of photoexcited charges. The synthesized UPTC was excited by ultraviolet, visible light and infrared light, exhibiting excellent full spectrum-response. Under near-infrared irradiation at 808 nm and 980 nm, UPTC effectively degraded rhodamine B (RhB). Under simulated sunlight, UPTC decomposed 88.6% malachite green, 92.2% rose bengal, and 90.8% RhB in 90 min. In photocatalysis, ·O2- played a dominant role. Moreover, the nanoheterojunction structure greatly improved photoexcited carrier separation. UPTC nanoheterojunction had excellent recycling capability. In actual sewage treatment, UPTC degraded 36.5% ammonia-nitrogen under simulated sunlight. In addition, UPTC exhibited sufficient biosafety. This study offers a fresh potential approach for producing highly efficient, stable, and biosafe nanoheterojunction photocatalysts for sewage treatment.

0D/2D Bi2WO6:Yb3+,Tm3+/Bi12O17Cl2 S-scheme heterojunction photocatalyst with enhanced full spectrum light activity by upconversion luminescence

To effectively utilize near-infrared light in the solar spectrum, expanding the spectral response range of photocatalysts is one of the main issues at present. Herein, a novel 0D/2D Bi2WO6:Yb3+, Tm3+/Bi12O17Cl2 S-scheme heterostructure with full spectral response is successfully synthesized through a hydrothermal method. The optimized Bi2WO6:Yb3+,Tm3+/Bi12O17Cl2 (1:1) photocatalyst degraded 68.2% and 59.1% of methylene blue (MB) and Rhodamine B (RhB) at 980 nm NIR light irradiation for 240 min, and the degradation of MB and RhB was 96.1% and 92.3% under visible light irradiation for 40 min, respectively. The enhanced photocatalytic activity could be attributed to these synergistic effects including the unique 0D/2D contact interface, the expanded photoresponse range, enhanced upconversion luminescence, as well as efficient energy transfer process between Yb3+/Tm3+ and Bi2WO6. Based on characterization and photocatalytic experiments, the introduction of Bi2WO6:Yb3+, Tm3+ can construct S-scheme heterojunctions with Bi12O17Cl2 and produce a full-spectrum response to sunlight. The result, the Bi2WO6:Yb3+, Tm3+/Bi12O17Cl2 photocatalysts possessed effective charge distribution and migration and maintained the excellent redox capacity of semiconductor materials. The hydroxyl radicals (·OH), superoxide radicals (·O2), and holes (h+) as active species played crucial roles in the degradation process. This work describes a potential method to construct S-scheme photocatalyst with great upconversion activity that possesses full spectral response for water pollution control.

Efficient photothermal catalytic CO2 reduction over in situ construction ZnIn2S4@Ni(OH)2/NiO Z-scheme heterojunction

Photocatalytic reduction of CO2 into valuable chemicals has been considered as a sustainable and environmentally friendly technology, which can simultaneously alleviate the energy crisis and environmental problems that have puzzled people for a long time. Herein, we successfully synthesize defective ZnIn2S4@Ni(OH)2/NiO (ZIS@NOH/NiO) Z-scheme heterojunction photocatalysts through solvothermal and low-temperature calcination strategies. The loading of Ni(OH)2 nanosheets can increase the specific surface area of photocatalyst, and form Z-scheme heterojunction with ZIS to improve the utilization of photogenerated electrons. It is worth noting that during the low-temperature calcination process, Ni(OH)2 is partially converted into NiO, and a large number of metal defects are formed, which reduces the bandgap of Ni(OH)2 and shows visible light response. In addition, the generated black defective NiO with full spectrum response and good photothermal effects can accelerate the migration of photogenerated carriers and reduce the catalytic reaction barrier of CO2. Consequently, the prepared ZIS@NOH/NiO exhibits a high yield (133.74 μmol g−1) and selectivity (86.2 %) for CO2 to CH4, which almost is 3.2 and 11.1 times than those of ZnIn2S4@Ni(OH)2 and ZnIn2S4, respectively. Furthermore, in-situ Fourier transform infrared spectroscopy (FTIR) analysis reveal the effective adsorption of CO2 on the ZnIn2S4@Ni(OH)2/NiO surface and the high selectivity of CH4. This work will provide meaningful prospects for designing a carbon dioxide reduction photocatalyst with high conversion and selective.

Photothermal catalytic oxidation of toluene by perovskite oxide/biochar nanocomposite: Effect of biomass incorporation

The utilization of waste biomass for the development of full-spectrum response photothermal catalysts shows significant potential in catalytic oxidation of volatile organic compounds (VOCs). Herein, perovskite oxide LaCoO3/biomass-derived biochar nanocomposite was synthesized by the sol–gel method using wasted pomegranate peel as complex agent. The introduction of biomass resulted in improved dispersion of LaCoO3 particles and enhanced the adsorption of toluene attributed to the large specific surface area and rich functional groups of biochar. Furthermore, the biochar exhibited strong broadband absorption and efficient photo-thermal conversion under light illumination, which not only activated the lattice oxygen on the surface to react with toluene, but also increased the transmission rate of photogenerated charge carriers. The defects of LaCoO3 caused by carbon doping facilitated the circulation of oxygen species, leading to the generation of more reactive oxygen species. When the mass ratio of LaCoO3 to biomass was 1:0.6, the LaCoO3/biochar composite exhibited excellent photothermal catalytic performance with a T90 value of 270 °C (temperature at 90 % degradation) and displaying high stability. Moreover, In-situ DRIFTS analysis revealed that both adsorbed oxygen and lattice oxygen participated in the reaction with toluene, promoting the ring-opening reaction of toluene and subsequent conversion of intermediates.

Earth-abundant insulator hydroxyapatite-based composite for full-spectrum photocatalytic degradation of 2, 4- dichlorophenol

Insulator hydroxyapatite (HAp) was chosen as a candidate to construct full-spectrum photocatalyst. Glucose as a functional precursor was incorporated into HAp by coprecipitated method, and the glucose-modified HAp was then calcined under nitrogen atmosphere. With the loss of OH- group in HAp and the decomposition of glucose during the calcination, oxygen vacancies (OVs) for regulating the band gap, graphitic carbon (GC) as a good electron acceptor, and a channel for rapid carrier separation via the C-O-Ca forming between OV-HAp and GC can be simultaneously achieved. The as-prepared OV-HAp/GC displayed full-spectrum response and rapid separation of carriers. Moreover, it showed high degradation performance for 2, 4-dichlorophenol (2, 4-DCP), phenol, and tetracycline under visible, NIR, and full-spectrum. This strategy is not only facile, but also exhibits a certain universality. This work opens a new window for full-spectrum photocatalysts construction based on insulators, and large-scale production for practical use can be expected.

Ti3C2-modified g-C3N4/MoSe2 S-scheme heterojunction with full-spectrum response effectively applied in photoreduction of CO2 to CO and CH4.

The energy shortages and global warming caused by the extensive use of fossil fuels are urgent problems to be solved at present. Photoreduction of CO2 is considered to be a feasible solution to two major global problems. The ternary composite catalyst g-C3N4/Ti3C2/MoSe2 was synthesized by hydrothermal method, and its physical and chemical properties were studied by an array of characterization and tests. In addition, the photocatalytic performance of this series of catalysts under full spectrum irradiation was also tested. It is found that the CTM-5 sample has the best photocatalytic activity, and the yields of CO and CH4 are 29.87 and 17.94 μmol g-1h-1, respectively. This can be ascribed to the favorable optical absorption performance of the composite catalyst in the full spectrum and the establishment of S-scheme charge transfer channel. The formation of heterojunctions can effectively promote charge transfer. The addition of Ti3C2 materials provides plentiful active sites for CO2 reaction, and its superior electrical conductivity is also conducive to the migration of photogenerated electrons.

ZnS/Ag2S decorated PES membrane with efficient near-infrared response and enhanced photocatalysis for pollutants photodegradation on high-turbidity water

By the combination of photocatalysis with membrane separation technology, a concurrent strategy of near-infrared (NIR) photocatalytic degradation and flow-through filtration for the treatment of antibiotics and dye effluent are proposed. After the deposition of homogeneous polyether sulfone (PES) layer with zinc acetate seeds as zinc oxide (ZnO) precursor on PES substrate membrane fabricated by non-solvent induced phase separation (NIPs), a photocatalytic membrane comprising of zinc sulfide (ZnS), silver sulfide (Ag2S), and PES substrate (ZnS/Ag2S@PES) was fabricated using successive ion layer adsorption and reaction (SILAR) and ion exchange method based on the conversion of ZnO into ZnS. ZnS/Ag2S@PES photocatalytic membrane with UV–vis-NIR full-spectrum response ability due to the construction of p-Ag2S/n-ZnS heterojunction can fulfil high pollutant photodegradation efficiency (methylene blue (MB) ∼ 70 % & tetracycline (TC) ∼ 58 %) in dead-end filtration by single pass. By simply two successive repeating units in flow-through filtration, more than 95 % of photodegradation efficiency for MB and TC can be achieved. More importantly, under NIR irradiation by the penetration of high-turbidity media and real turbidity wastewater, 68 % and 72 % of MB photodegradation efficiency can be respectively reached by only one unit within 1 h, which is expected to achieve the catalytic degradation to high-turbidity real industrial wastewater.

Molecular engineering of biomimetic donor-acceptor conjugated microporous polymers with full-spectrum response and an unusual electronic shuttle for enhanced uranium(VI) photoreduction

Realizing an efficient photochemical uranium reduction process using metal-free conjugated polymers is highly desirable, but is extremely challenging, as it requires a broad photo-response range and efficient electron transmission channels. Herein, three novel full-spectrum (200 ≤ λ ≤ 800 nm) responsive biomimetic donor–acceptor conjugated microporous polymers (CMPs) were successfully constructed to photoreduce uranium through a molecular engineering strategy. The optical band gap and built-in electric field of the CMPs were conveniently optimized via various quinone-containing acceptors. Furthermore, the quinone-containing block exhibited outstanding redox activity, which could serve as an unique electron shuttle to rapidly transfer electrons. Consequently, ECUT-TQ with 2,6-dibromobenzo[1,2-b:4,5-b']dithiophene-4,8-dione block exhibits a narrow band gap as low as 1.70 eV, a stronger built-in electric field and more efficient charge separation, achieving 97.4% photocatalytic U(VI) reduction efficiency with a photoreaction rate constant of 0.057 min−1. The exhaustive mechanism analysis illustrates that the dominant active species in the photocatalytic process where U(VI) is reduced to UO2 are photoelectrons and •O2– radicals. This work provides a novel approach for designing high-performance green biomimetic photocatalysts for removing radioactive pollution.

NIR-response amorphous FeOOH anchored BiO2-x for chlorophenols photodegradation via molecular oxygen activation

Chlorophenols (CPs) are universal and toxic pollutants in nature, as they have been widely detected in surface water, groundwater, sediment, ambient air, soil, and the human body. In this work, novel FeOOH/BiO2-x binary heterostructure composites with UV-Vis-NIR full-spectrum response were successfully constructed by anchoring highly dispersed amorphous FeOOH on BiO2-x nanosheets. A series characterization indicated the binary components were successfully obtained. The FeOOH/BiO2-x photocatalysts exhibited highly enhanced photocatalytic activity for the degradation of chlorophenols under UV-Vis-NIR full-spectrum irradiation. The amorphous FeOOH could effectively broaden the light response range, modulate the energy band structure and promote the separation and transfer of photogenerated electron-holes pairs, thus boosting the activation of molecular oxygen to generate •O2–. Furthermore, FeOOH/BiO2-x maintained excellent photocatalytic performance upon real solar light of varied irradiance for consecutive 7 days, indicative of great potential towards phenolic pollutants degradation in water. The redox couples of Fe3+/Fe2+ and Bi(3+x)+/Bi3+ also accelerate the efficient generation of reactive oxygen species over FeOOH/BiO2-x with improved durability. This work not only contributes to the design of full-spectrum responsive photocatalysts, but also provides a rational strategy for molecular oxygen activation towards the elimination of emerging contaminants.

Electron-buffer-mediated dual Z-scheme ZnSe/Ag2Se/AgBr heterojunction for efficient CO2 photocatalytic reduction

Design of photocatalysts with high-efficiency for sunlight utilization is one of the prerequisites for CO2 photoreduction. Besides, modulating a stable electron-donating environment to meet the energy barrier for CO2 reduction to CO is crucial. In this work, the ZnSe/Ag2Se/AgBr (ZAA) heterojunction was fabricated by growing the ZnSe on the AgBr surface accompanied by in-situ generation of Ag2Se between the two components by hydrothermal process. Results showed that the ZAA exhibited excellent light response ability over the full wavelength range. X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) demonstrated that the charge transfer of the ZAA conformed to dual Z-scheme mechanism, with the Ag2Se acting as an electron transfer bridge, which in turn acted as an electron reservoir to accelerate electron transfer, facilitating carriers’ separation. The highest CO yield of 54.14 µmol/g/h was obtained from the optimal ZAA-2, which was 11.76 and 10.44 times of pure ZnSe and Ag2Se, respectively. This work demonstrated the feasibility of a dual Z-scheme heterostructure with full spectrum response for offering stable electron-donating environment and improving electron transfer for enhanced photocatalytic activity.

Efficient photothermal catalytic oxidation of toluene by La1-xFexMnO3 with full spectrum response: The effects of Fe doping and photoactivation

Developing efficient photothermal catalysts with full spectrum response is one of the frontier topics in photothermal catalytic of VOCs. In this work, La1-xFexMnO3 (0 ≤ x ≤ 0.2) was synthesized via citrate sol-gel method. Under full spectrum illumination of 1.3 × 104 W/m2, La0.9Fe0.1MnO3 exhibited a more superior activity (86.7% toluene conversion and 84.6% CO2 yield). Through controlled experiments, not only the origin of photothermal activity, but the possible intrinsic drivers (Fe doping and photoactivation) of the enhanced activity were also revealed. Particularly, the mechanistic details of their facilitating reactions were thoroughly studied, where the improved mobility and activation of lattice oxygen played the primary role. Moreover, the co-effect of Fe doping and photoactivation on the resistance to complex gas components (SO2, H2O) and durability was systematically investigated. Eventually, the plausible pathways and mechanisms of toluene oxidation were proposed. This study provides a new insight into photothermal catalysts with full spectrum response for environmental remediation.

Bandgap-tuned barium bismuth niobate double perovskite for self-powered photodetectors with a full-spectrum response

Bandgap-tuned barium bismuth niobate double perovskite is achieved for self-powered broadband photodetectors with excellent photosensing performance.

Sensitive Chirality Measurements with Electrical Readout Utilizing the CISS Effect

AbstractChirality is a fundamental chemical property that can be found in almost all aspects of life. Generally, in nature chirality exists in only one of the possible enantiomeric forms. Bitter experience showed that chiral drugs having the same chemical composition but opposite chirality may have extremely different biological effects. It is therefore that detecting and quantifying chirality is important in multiple fields ranging from analytical and biological chemistry to pharmacology, biotechnology, and fundamental physics. To date, the most widely used analytical methods for chiral detection, remain the traditional approaches of measuring circular dichroism and optical rotation. However, these methods suffer from low signal‐to‐noise due to large time‐dependent backgrounds and require complicated optical setups. Recent works associate circular dichroism measurements with the Chiral Induced Spin Selectivity (CISS) spin current measurements. The CISS effect relates the probability of electron spin transmission through chiral molecules to chirality. Depending on the handedness of the molecule, electrons of a certain spin can traverse the molecule more easily in one direction than in the other. It is therefore that the CISS effect could be utilized to electronically measure chirality using spin currents and spin induced dipoles. The review summarizes the different approaches for utilizing the CISS effect for electrical measurements of chirality. Starting with a Hall device that can measure the chirality of the lowest energetic CD band of a monolayer in dry or wet systems. Presenting an enhancement of the effect as well as achieving a wider CD spectrum using electrical gating. Going down to 100 molecules limit with full spectrum response utilizing electro‐optical nano floret devices.

Enhanced photocatalytic degradation of organic pollutants and pathogens in wastewater using a full-spectrum response NaYF4:Yb,Tm@TiO2/Ag3PO4 nanoheterojunction

Organic and microbial pollution in water bodies is becoming increasingly problematic. However, only a few technologies can be used to simultaneously treat these pollutants in wastewater. In this study, nanosized NaYF 4 :Yb,Tm@TiO 2 /Ag 3 PO 4 heterojunctions with core–shell structures were fabricated via hydrothermal synthesis and an in situ deposition method. The synthesized ternary nanocomposites exhibited crystalline structures and the diameter of the nanoheterojunctions were ∼ 35 nm. Under light irradiation, fluorescence resonance energy transfer can be optimally performed among several constituting nanomaterials. The nanoheterojunctions exhibited wide spectral response capability. Under simulated sunlight irradiation, the nanoheterojunction degraded 91% Rhodamine B within 60 min. The minimum bactericidal concentrations of Staphylococcus aureus were 50 and 100 μ g mL − 1 under irradiation by a 980 nm laser and a xenon lamp, respectively, while that of Escherichia coli was 50 μ g mL − 1 under all irradiation conditions. These results are closely related to the manufactured core–shell heterojunction structure. In addition, the nanoheterojunction exhibited relatively low toxicity in the dark. Under near-infrared or simulated sunlight irradiation, the nanoheterojunction exhibited low cytotoxicity. Therefore, the nanoheterojunction broadens the spectral response range, increases the separation of photogenerated carriers, and enhances photocatalytic activity. To the best of our knowledge, this is the first time that a core–shell structured NaYF 4 :Yb,Tm@TiO 2 /Ag 3 PO 4 nanoheterojunction was fabricated and applied to treat organic pollutants and pathogenic bacteria. This research offers a powerful platform for the further development and application of NaYF 4 :Yb,Tm@TiO 2 /Ag 3 PO 4 nanoheterojunctions in the mitigation of organic and biological pollutants in wastewater. • The NaYF 4 :Yb,Tm@TiO 2 /Ag 3 PO 4 nanoheterojunctions exhibited wide spectral response capability. • Fluorescence resonance energy transfer among several constituting nanomaterials. • Under simulated sunlight irradiation, 91% Rhodamine B degraded within 60 min. • Excellent bactericidal activity with low cytotoxicity. • Application prospects include mitigation of organic and biological pollutants in wastewater.

Cathodoluminescence Spectroscopy in Graded InxGa1-xN.

InGaN materials are widely used in optoelectronic devices due to their excellent optical properties. Since the emission wavelength of the full-composition-graded InxGa1-xN films perfectly matches the solar spectrum, providing a full-spectrum response, this makes them suitable for the manufacturing of high-efficiency optoelectronic devices. It is extremely important to study the optical properties of materials, but there are very few studies of the luminescence of full-composition-graded InxGa1-xN ternary alloy. In this work, the optical properties of full-composition-graded InxGa1-xN films are studied by cathodoluminescence (CL). The CL spectra with multiple luminescence peaks in the range of 365-1000 nm were acquired in the cross-sectional and plan-view directions. The CL spectroscopy studies were carried out inside and outside of microplates formed under the indium droplets on the InGaN surface, which found that the intensity of the light emission peaks inside and outside of microplates differed significantly. Additionally, the paired defects structure is studied by using the spectroscopic method. A detailed CL spectroscopy study paves the way for the growth and device optimization of high-quality, full-composition-graded InxGa1-xN ternary alloy materials.

A novel double S-scheme photocatalyst Bi7O9I3/Cd0.5Zn0.5S QDs/WO3−x with efficient full-spectrum-induced phenol photodegradation

In this work, Bi7O9I3/Cd0.5Zn0.5S QDs/WO3−x ternary heterojunction with full spectrum response was prepared and applied in the photodegradation of phenol. The results of photocatalytic experiments showed that the prepared Bi7O9I3/Cd0.5Zn0.5S QDs/WO3−x heterojunction had the highest performance under full spectrum, visible and near-infrared light irradiation, and the reaction rates were 4.02, 3.75 and 5.71 times that of pure Bi7O9I3, respectively. This performance improvement results from the construction of double S-scheme heterojunction and the full-spectrum response, which had effective charge distribution and migration as well as an excellent response to sunlight. In addition,·OH and·O2- took the lead role in the process of photodegradation. Combined with the free radical-trapping experiment, ESR experiment and DFT theoretical calculation, the photocatalytic mechanism of double S-scheme system was proposed. This work is contributory to designing novel photocatalytic materials with dual S-scheme heterojunction and the efficient purification of wastewater in environmental remediation.

Phase engineering-defective 1 T @ 2 H MoS2 nanoflowers as excellent full spectrum photocatalyst

The photocatalytic efficiency is greatly limited due to the narrow light response range and the low charge separation of MoS2. The 1 T @ 2 H phase MoS2 nanoflowers with controllable fabrication of defect levels were successfully prepared with excellent full-spectrum response by controlling various amounts of excesses thiourea as a sulfur source. Meanwhile, the 1 T @ 2 H MoS2-S4 sample with the optimal S defect level showed excellent photocatalytic degradation activity under UV-Vis and NIR light, with a degradation rate of 95.0% and 99.1% respectively. The EDS, EPR and UV-Vis-NIR absorption results show that the S defects has a significant effect on expanding the light absorption response range and enhancing the light absorption capacity. Compared with 1 T @ 2 H MoS2, the light absorption capacity of 1 T @ 2 H MoS2-S4 increased by 2.2 times due to the introduction of S vacancy. Ulteriorly, the introduction of 1 T phase has an excellent optimization effect on the photogenerated charge transmission path due to its own higher electron concentration and conductivity. Therefore, defect engineering and phase engineering are of great significance to the investigate of full-spectrum photocatalytic materials.