Effective Separation Research Articles

Furrow and tubular channels for continuous diffusion dialysis

Diffusion dialysis (DD) is effective to separate and recover acid component from acid feed, but the performance is restricted by the narrow and short flowing channels due to the conventional flat membranes and plate-and-frame dialyzer. Hence, tubular membranes, as prepared from polyvinyl alcohol (PVA), are serially connected to form a long tubular channel for running acid feed including H2SO4/FeSO4 and HCl/FeCl2. The tubular membranes are installed in 3D-printing dialyzers, which provide a long furrow channel for running water. Hence, furrow and tubular channels are formed for continuous DD process. As the number of tubular membranes in furrow channel increases from 1, 6 to 12, the channel length increases from 80, 300 to 600 cm.The tubular membrane shows tensile strength of 3.0 – 5.2 MPa and elongation at break of 251 – 316% after swelling in water or acid feeds. The membrane packing density in dialyzer reaches up to 425 cm2‧L-1, with the weight percent of 5.2%. Continuous DD process shows water reverse osmosis (from -1.7 to -15.4 mol‧m-2‧h-1) due to the higher pressure in the tubular channel. As the channel length increases from 80 to 600 cm, the ion transport rates increase as reflected by the recovered acid concentration (Cd-H), recovery ratio (RH) and Fe2+ rejection ratio (ηFe). The Cd-H increases from 0.83 to 2.08 mol‧L-1 (M), the RH increases from 29.6% to 70.0%, and the ηFe decreases from 97.9% to 86.5% at the flow rate of 1.49 L m-2 h-1 for the H2SO4/FeSO4 after 8 h. As for the HCl/FeCl2, the RH and ηFe can be balanced at 83.1% and 80.1% correspondingly when the channel length is 600 cm, and the residual acid concentration is only 0.17 – 0.22 M. The DD performances are generally stable after an acid immersion of seven days. Hence, a simple and effective separation can be realized by the long channels.

Cost effective selective separation of indium and germanium from zinc processing waste leach liquor using D2EHPA-YW100 synergistic system and selective stripping with HCl and NH4F

Indium and germanium are rare elements and contribute to supporting materials for contemporary high technology new materials. Research and development of efficient separation and extraction of indium and germanium have important practical significance. A new process of “one step extraction and stepwise stripping” is proposed in this work to coextract indium and germanium with D2EHPA-YW100 synergistic system of Di(2-ethylhexyl) phosphoric acid (D2EHPA) and C7–9 hydroxamic acid (YW100) denoted by D2EHPA-YW100. In the coextraction process, 98.9 % of indium and 99.9 % germanium were extracted utilizing an organic phase consisting of YW100 (1.4 %), D2EHPA (15 %) and sulfonated kerosene (83.6 %). During the two-step stripping process, 99.9 % of indium was selectively stripped from the loaded organic phase in step-1 using 4 M HCl. In step-2, 99.5 % of germanium was stripped using a 1 M NH4F solution. This separation resulted the enrichment of germanium concentration by 6–7 fold and indium concentration by 19 fold. This method has four advantages: (i) simplifies the separation process, (ii) reduces equipment investment by nearly 50 %, (iii) minimizes extraction agent loss, and (iv) reduces management and labor costs.

Magnetic field and photon co-enhanced S-scheme MXene/In2S3/CoFe2O4 heterojunction for high-performance lithium-oxygen batteries

Under the spotlight for their potential to reduce over-potential, photo-assisted Li–O2 batteries still face a key challenge: the rapid recombination of photo-generated electron-hole pairs, which limits their efficiency. In this study, we address this limitation by designing a Li–O2 battery that integrates both photo and magnetic field assistance, using an S-scheme MXene/In2S3/CoFe2O4 heterojunction photocathode. This unique combination enhances visible light absorption and generates a strong built-in electric field, facilitating effective charge separation and boosting photocatalytic activity. During discharge, photo-generated electrons participate in the oxygen reduction reaction, while photo-induced holes contribute to the decomposition of discharge products during charging. Furthermore, the introduction of a magnetic field, confirmed through vibrating sample magnetometer, Mössbauer spectroscopy, X-ray absorption near edge structure, and cyclic voltammetry analyses, enhances electron-hole separation via Lorentz forces and spin–orbit coupling, accelerating the formation and decomposition of Li2O2. With this synergistic approach, the battery achieves a high specific capacity of 26500 mAh g−1, ultra-low oxygen reduction/evolution reaction over-potentials of 0.08 V/0.17 V, and a long cycle life of 2000 cycles with energy efficiency of 98.11 %. This work demonstrates the promising potential of combining photo and magnetic field effects to improve the electrochemical performance of Li–O2 batteries, opening new avenues for high-performance energy storage systems.

Facile Synthesis of Bandgap-Engineered N-Doped MgO/g-C3N4 Nanocomposites for Enhanced Sunlight-Driven Photocatalytic Degradation of Organic Dyes

This study tests the theory of using a p-n junction to inhibit the recombination of photo-generated electrons and holes in N-MgO/g-C3N4 for the photocatalytic degradation of methylene blue (MB) dye. While the use of n-type semiconductor junctions with g-C3N4 for bandgap narrowing is well-studied in dye degradation, this research explores the innovative application of nitrogen (N)-doped MgO to create a p-type junction with n-type g-C3N4. The N-MgO/g-C3N4 nanocomposites were designed and synthesized to leverage both the bandgap narrowing effect and the formation of a p-n junction. The results demonstrate that these nanocomposites can effectively degrade MB dye under sunlight, achieving over 90% degradation efficiency with a bandgap of 2.63 eV. Under high pH conditions, the degradation efficiency further increased to 94%. The enhanced photocatalytic activity of the N-MgO/g-C3N4 composite is attributed to the formation of a heterojunction, which facilitates efficient separation and transmission of photo-induced charge carriers. This study discusses the detailed mechanism of this enhanced activity, emphasizing the role of the p-n junction in promoting effective charge separation and transfer, thereby improving the photocatalytic performance under sunlight.

Conformational changes in polysaccharide-based chiral selectors induced by mobile phase composition: Effects on enantioselective retention and enantiomer elution order reversal.

Despite having identical physicochemical properties, chiral molecules require effective separation techniques due to their distinct pharmacological effects. Polysaccharide-based chiral stationary phases (CSPs) are widely used for chiral separations in liquid chromatography; however, the mechanisms of chiral recognition are not well understood. This research explored the adsorption, retention, and chiral recognition mechanisms of three amylose-based CSPs: Chiralpak ID, IF, and IG. The effect of mobile phase composition on enantioselective retention was examined using four acyloin-type chiral solutes in normal-phase mode. For pantolactone (PL) and methyl mandelate (MM), reversals in enantiomer elution order were observed with ID and IG sorbents, respectively, at 2 vol.% isopropanol (iPrOH). As the iPrOH concentration increased, the adsorption of MM enantiomers reached an energetic barrier at this concentration, causing discontinuities in the enthalpy-entropy compensation. Conversely, while the reversal behavior of PL was also attributed to conformational changes in the ID polymer, it did not encounter an energetic barrier and thus remained in line with the enthalpy-entropy compensation. For the IF sorbent, no significant changes in enantioselective retention or enthalpic curves were noted. Nevertheless, a reversal was observed for benzoin (B) enantiomers on the IF sorbent at 10 vol.% iPrOH. It was postulated that the IF sorbent contains two chiral sites with opposing recognition abilities, and their relative contributions to the apparent enantioselectivity of B are influenced by the iPrOH concentration. These findings highlight the importance of conformational changes in chiral selectors, driven by mobile phase composition, in chiral recognition mechanisms. Understanding these effects is crucial for developing predictive models of chiral retention and enhancing optimization of chiral separation processes.

"Electron trap" modified type-I heterojunction CdS/CoSe/graphdiyne photocatalyst synergistically promotes photocatalytic hydrogen production

Modifying the carrier dynamics in heterojunction photocatalysts is a direct and effective strategy to enhance photocatalytic hydrogen production. Herein, graphdiyne (GDY) is loaded onto CdS/CoSe using a solvothermal method, and the CdS and GDY form a type-I heterojunction. In addition, the highly conductive metal-like material CoSe acts as an "electron trap" to transfer electrons from GDY to CoSe, which promoting the effective separation of photo-generated electrons and holes, further improving the performance of photocatalytic hydrogen production. The hydrogen evolution rate of CdS/CoSe/GDY (0.17mmol·h-1) is 4.25 and 1.88 times for CdS (0.04mmol·h-1) and CdS/CoSe (0.09mmol·h-1). In-situ X-ray photoelectron spectroscopy (XPS), Electron Paramagnetic Resonance (EPR) and Density functional theory (DFT) calculations and other characterizations demonstrate that the significantly improved photocatalytic performance is not only due to the fast electron transfer and separation by close contact, but also to the synergistic effect between the type-I heterojunction and the "electron trap". In conclusion, this work enriches the study of type-I heterojunction photocatalytic systems and provides new research ideas for the design of efficient photocatalysts.

An environmentally effective separation strategy of chitin from shrimp shells based on steam explosion and supercritical carbon dioxide

An environmentally effective separation strategy of chitin from shrimp shells based on steam explosion and supercritical carbon dioxide

Separation of valuable materials from spent lithium-ion battery based on granulation regulation.

Recycling of spent lithium-ion batteries has attracted worldwide attention to ensure sustainability of electric vehicle industry. Pretreatment as an essential step for recycling of spent LIBs is critical to ensure the recovery efficiency and quality of black mass which is used for further materials regeneration. Usually, high temperature pyrolysis, at around 600°C is required during the pretreatment to achieve effective separation of the black mass that is binding on aluminium foils with polyvinylidene fluoride binder. In this research, a low temperature and energy effective method is demonstrated by introducing a controlled frictional granulation in the subsequent step. With heat treatment at below 300 ℃, the oxidation of aluminium foil and generation of fluorine-containing waste gas can be highly supressed. As a consequence, the recovery rate of black mass can be increased to 98.80% with only 0.05% Al loss. Compared with the high-temperature pyrolysis and shear crushing methods, the energy consumption was significantly reduced by 48.74%. Additionally, the proportion of aluminium particles below 75μm was reduced from 12.6% to 1.9% comparing with traditional high temperature pyrolysis, which eliminates the possibility of explosion of aluminium particles. This research provides a low-carbon footprint strategy for treatment of complex electronic waste.

Characterization of solid particles with different particle sizes in high-temperature coal tar pitch

ABSTRACT High-temperature coal tar pitch (HCTP) serves as a crucial precursor for high-quality carbon materials, while solid particle (SP) characteristics significantly influence the properties of the pitch. This study explores the compositional differences of SPs across various sizes to facilitate their effective separation. We employed ultrasonic graded centrifugation to isolate seven SP types of different sizes and analyzed their properties using SEM, SEM-EDS plane scanning, laser particle size analysis (LPSA), organic element analysis (EA), FT-IR, ICP-MS, and XRD. Our results reveal distinct variations in the SP distribution by particle size. As the particle size decreases, the proportion of particles in the 1–100 μm range decreases, while ultrafine particles (0.01–0.1 μm) become more prevalent. The carbon content in SPs initially increases and then decreases with smaller particle sizes, reaching a peak in medium-sized particles. Non-carbon impurities such as Si, S, Zn, Pb, Ca, Fe, and inorganic ash are concentrated in larger particles (SP1–SP2) and smaller particles (SP6–SP7). Notable inorganic compounds like PbS, ZnS, and FeS are found across all sizes, whereas SiO2 and CaCO3 are restricted to larger particles (SP1–SP2). Furthermore, smaller particles exhibit greater specific surface areas and pore volumes.

Empowering wastewater treatment with step scheme heterojunction ternary nanocomposites for photocatalytic degradation of nitrophenol

The ongoing challenge of water pollution necessitates innovative approaches to remove organic contaminants from wastewater. In this work, new two-dimensional S-scheme heterojunction photocatalysts Bi2O3/CdS and MoS2/Bi2O3/CdS that are intended for the effective photocatalytic destruction of 4-nitrophenol, a dangerous organic pollutant, are synthesized and characterized. Utilizing a solvothermal method, successfully generated these ternary nanocomposites, which were characterized through various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), high resolution transmission electronmicroscopy (HRTEM), Brunauer-Emmett-Telle (BET) and diffuse reflectance spectroscopy (DRS). Our results demonstrated that the Bi2O3/CdS heterojunction achieved an 86% degradation rate of 4-nitrophenol, while the MoS2/Bi2O3/CdS composite exhibited exceptional photocatalytic performance, achieving nearly complete degradation (99%) within 120 min under visible light irradiation. Most importantly the improved photocatalytic activity of MoS2/Bi2O3/CdS heterojunction originated from the release of internal electric field in S-scheme heterojunction. This enhanced activity is attributable to the synergistic effects of the heterojunctions that facilitate more effective charge separation and generation with more OP and RP confirmed the composite synthesis using S-scheme. The S-scheme is further confirmed by XPS, DRS, XPS-VB and photocurrent response. These findings highlight the promising application of these advanced photocatalysts in real-world wastewater treatment processes, offering a sustainable solution to combat water pollution.

Process upgradation and kinetic modeling of high-ash non-coking coal flotation using bio-based collector for enhanced clean coal recovery

ABSTRACT The reduction of ash content, contributed by inorganic mineral matter, and recovery of carbon values in a high ash non-coking coal was studied in a laboratory-scale mechanical flotation cell using a bio-collector (PSO) derived from the pumpkin seeds for clean coal recovery. Surface characterization of PSO (GCMS, FTIR) and untreated/PSO-treated coal (contact angle, FTIR) indicated potential interaction between PSO and the coal surface, enhancing its hydrophobicity, while XRD analysis confirmed successful rejection of ash-forming inorganic gangue minerals into tailings, signifying effective clean coal separation from the gangue. The input parameters, such as PSO dosage, frother MIBC dosage, and airflow rate (AFR), were enhanced to attain best process responses, i.e. yield, ash, and fixed carbon of the final clean coal. The use of PSO significantly reduced the ash content of feed coal from 32% to as low as 9.86% in the final clean coal while simultaneously increasing the fixed carbon content from 35% to 61.15% and the gross calorific value from 4966 Kcal/Kg to 6318 Kcal/kg. A clean coal product having high fixed carbon of 61.15% with 11.29% ash content and 70.14% yield was obtained at PSO dosage of 10.73 Kg/t, MIBC dosage of 0.93 Kg/t and at AFR of 2.5lpm. The kinetic study revealed a high recovery of combustible materials (~88%) and low ash recovery (~46%) at a flotation time of 480 seconds. Based on the kinetic model discrimination analysis, it was found that the first-order fits well with the experimental data for combustible and ash recovery. This study illustrates the efficacy of pumpkin seed oil (PSO) as a potential bio-collector for the flotation of non-coking coal, enhancing the coal quality by selectively reducing mineral matter content and leading to substantial economic and environmental advantages.

Theoretical Design for Thorium-Containing Two-Dimensional Materials.

Actinide elements are characterized by their unique electronic correlations, variable valence states, and localized 5f electrons, leading to unconventional electronic and topological properties in their compounds. The distinctive physical properties of actinide materials are maintained in low-dimensional forms, yet two-dimensional (2D) actinide materials remain largely unexplored due to their scarcity and the experimental challenges posed by their radioactivity. To fill the knowledge gap in 2D actinide materials, we theoretically designed a series of stable thorium-containing 2D materials, including MXenes, chalcogenides, halides, and other compounds with unique structures. These novel thorium-containing 2D materials show excellent thermodynamic, mechanical, and dynamical stability. Their electronic structures and potential applications were investigated. Considering the proper band edge positions, strong visible light absorption, and effective separation of photogenerated electron-hole pairs, ThPSe3 is proposed as a promising photocatalyst for water splitting. Our work significantly expands the 2D actinide materials family, and further opens new avenues for their experimental realization and applications.

Treatment and Valorization of Waste Wind Turbines: Component Identification and Analysis.

Recycling end-of-life wind turbines poses a significant challenge due to the increasing number of turbines going out of use. After many years of operation, turbines lose their functional properties, generating a substantial amount of composite waste that requires efficient and environmentally friendly processing methods. Wind turbine blades, in particular, are a problematic component in the recycling process due to their complex material composition. They are primarily made of composites containing glass and carbon fibers embedded in polymer matrices such as epoxies and polyester resins. This study presents an innovative approach to analyzing and valorizing these composite wastes. The research methodology incorporates integrated processing and analysis techniques, including mechanical waste treatment using a novel compression milling process, instead of traditional knife mills, which reduces wear on the milling tools. Based on the differences in the structure and colors of the materials, 15 different kinds of samples named WT1-WT15 were distinguished from crushed wind turbines, enabling a detailed analysis of their physicochemical properties and the identification of the constituent components. Fourier transform infrared spectroscopy (FTIR) identified key functional groups, confirming the presence of thermoplastic polymers (PET, PE, and PP), epoxy and polyester resins, wood, and fillers such as glass fibers. Thermogravimetric analysis (TGA) provided insights into thermal stability, degradation behavior, and the heterogeneity of the samples, indicating a mix of organic and inorganic constituents. Differential scanning calorimetry (DSC) further characterized phase transitions in polymers, revealing variations in thermal properties among samples. The fractionation process was carried out using both wet and dry methods, allowing for a more effective separation of components. Based on the wet separation process, three fractions-GF1, GF2, and GF3-along with other components were obtained. For instance, in the case of the GF1 < 40 µm fraction, thermogravimetric analysis (TGA) revealed that the residual mass is as high as 89.7%, indicating a predominance of glass fibers. This result highlights the effectiveness of the proposed methods in facilitating the efficient recovery of high-value materials.

Multiple Exciton Generation on Doped Wide-Band Semiconductor Photoanode with Hierarchical Quantum Structure.

The multiple exciton generation (MEG) effect, which produces multiple photo-generated charge carriers from a single high-energy photon absorption by a semiconductor with a narrow bandgap, has the potential to revolutionize photovoltaic, photoelectric detection, and other technologies. Here, this work finds that the surface carbon-modified wide-bandgap photoanode with hierarchical quantum structure can drive a photoelectrochemical reaction with a quantum efficiency exceeding 145% by the first time. More studies reveal that the presence of the MEG effect in the MEG-CdS photoanode is attributed to the formation of high-quality surface C-modified CdS quantum nanosheets on CdS bulk film by in situ, this hierarchical quantum structure leads to quantum confinement effects that increase effective Coulomb interaction for driving MEG and decrease competition for thermal exciton cooling. The acceptor level introduced by carbon reduces the MEG threshold (approximately twice the energy level difference) and collaborates with the built-in electric field of the C-CdS/bulk-CdS homojunction to enable the effective generation and separation of photo-generated charge carriers. The internal quantum efficiency of the MEG-CdS photoanode reaches up to a recording value of 145%, providing a novel perspective on the contribution of surface-modified wide-band semiconductors and their quantum effects in the application of MEG.

Strong Interfacial Interaction in Polarized Ferroelectric Heterostructured Nanosheets for Highly Efficient and Selective Photocatalytic CO2 Reduction.

Heterojunctions are sustainable solutions for the photocatalytic CO2 reduction reaction (CO2RR) by regulating charge separation behavior at the interface. However, their efficiency and product selectivity are severely hindered by the inflexible and weak built-in electric field and the electronic structure of the two phases. Herein, ferroelectric-based heterojunctions between polarized bismuth ferrite (BFO(P)) and CdS are constructed to enhance the interfacial interactions and catalytic activity. The intrinsic polarization field depending on the ferroelectric state causes significant electrostatic potential difference and energy-band bending. This helps overcome the unsatisfactory redox potential that differs from the classical catalytic mechanism, and synergy from the heterostructure facilitates effective separation and transfer of photogenerated charges with an extended lifetime (>20ns) and significantly enhanced photovoltage (1002 times that of BFO). The optimized charge carrier dynamics allow the heterojunction to achieve a much higher CO yield compared to state-of-the-art ferroelectric-based photocatalysts, and 85.46 and 23.47 times higher than those of pristine CdS and BFO, respectively. Moreover, it maintains an impressive 100% product selectivity together with excellent repeatability and cycling. This work not only sheds light on how a strong inherent polarity promotes the performance of heterojunction photocatalysts but also provides new insights for designing efficient photocatalytic CO2RR.

Towards an Automated Design Evaluation Method for Wire Arc Additive Manufacturing

Freedom of design and the cost-effective production of structural parts have led to much research interest in Wire Arc Additive Manufacturing (WAAM). Nevertheless, WAAM is subject to design constraints and fundamentally differs from other additive manufacturing processes. Consequently, design guidelines and supporting design evaluation tools adapted to WAAM are needed. One geometric approach to design evaluation is the use of a three-dimensional medial axis transformation (3D-MAT) to derive local geometry indicators. Previous works define the thickness and radius indicators. In this work, the angle between opposing faces and a mass gradient indicator are added. To apply the literature design rules regarding wall thickness, clearance, bead angle, and edge radius to specific geometry regions, features are classified by the indicators. Following a literature suggestion, wall and corner regions are differentiated by the angle indicator. An angle of 65° is identified as an effective separation limit. Additionally, the analogy of Heuvers’ spheres to the MAT helps estimate a limit of kH−1kH+1 for the mass gradient (kH: Heuvers’ factor). Finally, tests on example parts demonstrate the method’s effectiveness in verifying compliance to the specified rules. With a numerical complexity of O(n2), this method is more efficient than finite element analyses, providing early feedback in the design process.

Weakly Supervised Nuclei Segmentation with Point-Guided Attention and Self-Supervised Pseudo-Labeling.

Due to the labor-intensive manual annotations for nuclei segmentation, point-supervised segmentation based on nuclei coordinate supervision has gained recognition in recent years. Despite great progress, two challenges hinder the performance of weakly supervised nuclei segmentation methods: (1) The stable and effective segmentation of adjacent cell nuclei remains an unresolved challenge. (2) Existing approaches rely solely on initial pseudo-labels generated from point annotations for training, and inaccurate labels may lead the model to assimilate a considerable amount of noise information, thereby diminishing performance. To address these issues, we propose a method based on center-point prediction and pseudo-label updating for precise nuclei segmentation. First, we devise a Gaussian kernel mechanism that employs multi-scale Gaussian masks for multi-branch center-point prediction. The generated center points are utilized by the segmentation module to facilitate the effective separation of adjacent nuclei. Next, we introduce a point-guided attention mechanism that concentrates the segmentation module's attention around authentic point labels, reducing the noise impact caused by pseudo-labels. Finally, a label updating mechanism based on the exponential moving average (EMA) and k-means clustering is introduced to enhance the quality of pseudo-labels. The experimental results on three public datasets demonstrate that our approach has achieved state-of-the-art performance across multiple metrics. This method can significantly reduce annotation costs and reliance on clinical experts, facilitating large-scale dataset training and promoting the adoption of automated analysis in clinical applications.

Construction of Cu2MoS4/ZnO Heterostructures and Mechanism of Photocatalytic Hydrogen Production.

Constructing wide and narrow band gap heterogeneous semiconductors is a method to improve the activity of photocatalysts. In this paper, CMS/ZnO heterojunctions were prepared by solvothermal loading of ZnO particles on the surface of Cu2MoS4 nanosheets. The photocatalytic H2 precipitation rate is about 545 μmol·g-1·h-1, which is 6.8 times that of Cu2MoS4 and 3 times that of ZnO without any cocatalyst. After etching modification of CMS, the photocatalytic hydrogen production efficiency of the ECMS/ZnO heterojunction is further improved. Its hydrogen production efficiency reaches about 1115 μmol·g-1·h-1, which is 9 times that of ECMS and 6 times that of ZnO. The reasons are mainly attributed to the following two factors: (1) the formation of the ECMS/ZnO type-II-type heterojunction facilitates the effective separation of photogenerated electrons and holes; (2) the band structure of Cu2MoS4 was optimized by etching modification, which made the ECMS/ZnO heterojunction have lower interfacial charge transfer resistance and improved the photocatalytic hydrogen production activity of the heterojunction.

Photocatalytic NO Removal by Ternary Composites Bi12GeO20/BiOCl/W18O49 Using a Waste Reutilization Strategy

Heterojunction creation is demonstrated as an effective strategy to enhance the transfer and separation of charge carriers, which is beneficial for subsequent photocatalytic reactions. In this study, “sea urchin-like” W18O49 was in situ-grown on the surface of Bi12GeO20 through a hydrothermal process, and the released Cl− anions tended to produce BiOCl simultaneously. Systematical characterizations confirmed the construction of ternary composites Bi12GeO20/BiOCl/W18O49 (GBW), in which Type I and Z-scheme models were integrated to promote charge carrier migration and separation by combining the structural merits of both models. Under UV–visible light, the catalytic performance of the as-synthesized samples was tested in terms of NO oxidation removal. Compared to pure Bi12GeO20, the composite GBW5 showed the highest NO photocatalytic removal efficiency of 42%, which was nearly four times that of pure Bi12GeO20. These improvements were mainly due to enhanced light absorption, suitable morphological features, effective separation of charge carriers, and the boosted generation of reactive species in the GBW series. This study paves the way for the construction of Bi12GeO20-based ternary composites using a comprehensive utilization of waste method and the employment of the composites for the photocatalytic removal of low concentrations of NO at the ppb level.

High-performance broadband photodetectors based on MnSe/SnS2 heterojunction

Abstract Two-dimensional (2D) materials have emerged as promising candidates for broadband photodetectors due to their unique optoelectronic properties. However, intrinsic defects and limited spectral response hinder their practical applications. In this study, we developed a novel 2D heterojunction photodetector by combining non-layered p-type MnSe nanosheets with layered n-type SnS2 flakes. The MnSe nanosheets were synthesized using chemical vapor deposition, while the SnS2 flakes were obtained through mechanical exfoliation. The fabricated MnSe/SnS2 heterojunction device exhibited rectifying behavior with an impressive on/off current ratio over 5000. Remarkably, the photodetector demonstrated a broad spectral response ranging from ultraviolet to near-infrared (405–1060 nm), achieving an exceptionally high responsivity of 10 A W−1, a detectivity of 3.06 × 1010 Jones, and an external quantum efficiency of 3068%. The enhanced performance was attributed to the type-II band alignment and built-in potential of the heterojunction, which facilitated effective separation of photogenerated carriers. Furthermore, the device exhibited significant photovoltaic characteristics, enabling self-powered imaging in visible range. This study highlights the potential of 2D non-layered materials in combination with traditional 2D layered materials for the development of high-performance, broadband photodetectors with improved efficiency and self-powered capabilities.