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Precursor-reforming strategy induced g-C3N4 microtubes with spatial anisotropic charge separation established by conquering hydrogen bond for enhanced photocatalytic H2-production performance
摘要： Precursor-reforming strategy induced graphitic carbon nitride (g-C3N4) with different morphologies for enhanced photocatalytic hydrogen (H2) evolution activity is highly desirable. Herein, g-C3N4 microtubes (mg-C3N4) with adjustable closure degree of microtube orifice and spatial anisotropic charge separation are established by conquering hydrogen bond during thermally exfoliate precursor. Compared to the bulk g-C3N4 (bg-C3N4) and ultrathin g-C3N4 (ug-C3N4), the tubular structure endows mg-C3N4 with spatial anisotropic charge separation that accelerates transfer of charge carriers. As expected, the photocatalytic H2 evolution (PHE) activity of mg-C3N4 has been obviously enhanced. Particularly, the mg-C3N4-24 shows the best PHE activity (957.9 μmol h-1g-1), which is over 18.72 and 3.77 times higher than the bg-C3N4 and ug-C3N4, respectively. In addition, selective photo-deposition experiment results reveal a charge carriers migration behavior that photoproduction electrons migrate to the outer shell and holes prefer to move onto the inner shell of mg-C3N4, thus achieving efficient spatial anisotropic charge separation. We firmly believe that the work presents significant advancement for the design of other materials by precursor-reforming strategy.
关键词： Charge carriers,Precursor-reforming,mg-C3N4,Spatial anisotropic,PHE
更新于2025-11-14 15:23:50
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Photocatalytic removal of phenanthrene and algae by a novel Ca-Ag3PO4 composite under visible light: Reactivity and coexisting effect
摘要： In this study, the feasibility of a novel Ca-Ag3PO4 composite with visible light irradiation for the phenanthrene (PHE) degradation and algae inactivation in artificial seawater was firstly investigated. The experimental findings revealed that Ag3PO4 phase was sucessfully formed on the Ca-based material, and the presence of Ca-based material could effectively keep Ag3PO4 particles stable. An excellent performance on PHE degradation or algae inactivation was observed from Ca-Ag3PO4 composite under visible light irradiation. The degradation of PHE or inactivation of algae not only could be efficiently achieved in the single mode, but also could be successfully achieved in the coexisting mode. Above 96 % of PHE and algae were simultaneously removed within 12 h in the Ca-Ag3PO4/visible light system. It was further observed that the degradation of PHE and/or inactivation of algae increased with the increase of Ca-Ag3PO4 dosage. HO? was the primary radical responsible for PHE degradation, whereas HO? and Ag+ released from Ca-Ag3PO4 mainly contributed to the algae inactivation. A possible mechanism involving the catalytic removal of PHE and algae by Ca-Ag3PO4 under visible light irradiation was proposed. This study provides helpful guide for the simultaneous removal of various pollutants in real seawater.
关键词： Ag3PO4,Algae,Photocatalytic,Advanced oxidation processes (AOPs),Visible light,Phenanthrene (PHE)
更新于2025-09-23 15:23:52
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Pinpointing the l-phenylalanine binding sites of TyrR using biosensors and computer-aided simulation
摘要： Objectives To determine the binding sites for L-phenylalanine in TyrR protein via a rational mutation analysis combining biosensors and computer-aided simulation. Results TyrR protein of Escherichia coli is the chief transcriptional regulator of several genes essential for the biosynthesis and transport of aromatic amino acids. The identification of ligand-binding sites is often the starting point for protein function annotation and structure-based protein design. Here we combined computer-aided prediction methods and biosensors to identify the ligand-binding sites for L-Phe in TyrR protein. Conclusions Residues at positions 160, 173 and 184 of TyrR protein are important for transcriptional activation of target genes tyrP induced by L-Phe, which indicates that they are the bona fide L-Phe binding sites of TyrR protein.
关键词： L-Phe binding site,Computer-aided simulation,TyrR protein,Biosensor
更新于2025-09-19 17:15:36
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Photodetectors with 384 × 288 Matrix Elements for the Infrared Range of 8–10 Microns
摘要： Design and fabrication of photosensitive array elements in the 384 × 288 element format with a step of 25 μ m with a long wavelength limit of sensitivity at 0.5 to approximately 9.5 μ m were performed. The circuit and topology were developed, according to which matrix high-speed multiplexers are manufactured in the form of 384 × 288 elements with a step of 25 microns, which provide operating modes at a clock frequency of up to 20 MHz. The 384 × 288 element hybrid photodetector (PD) format in 25 μ m increments has an average Noise Equivalent Temperature Difference (NETD) of less than 30 mK, while the number of working elements was more than 97%. Examples are given of using the microscanning system to reduce defective pixels in an image frame and/or increase the frame format to 768 × 576. It is shown that as a result of the use of microscans in a thermal imaging channel based on the developed PD during the transition to the 768 × 576 format, an improvement in spatial resolution of 1.4 times was obtained for the same minimum resolved temperature difference (MRTD), while the MRTD at a frequency of 0.44 mrad-1 decreased from 1.6 to 0.9 K compared to the original 384 × 288 format.
关键词： MRTD,topology,microscanning,CMT,frame rate,spatial resolution,molecular beam epitaxy,format,PD,NETD,PHE
更新于2025-09-19 17:13:59
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Application of derivative emission fluorescence spectroscopy for determination of ibuprofen and phenylephrine simultaneously in tablets and biological fluids
摘要： Two sensitive, rapid, and accurate derivative emission spectrofluorimetric methods applying zero crossing techniques were developed for simultaneous determination of binary mixtures of ibuprofen (IBU) and phenylephrine hydrochloride (PHE) in pure powder, synthetic mixture and combined tablets. The proposed methods were performed via measuring the intersected drug derivative amplitude of one drug at the zero crossing points for the other one and vice versa. The two methods rely on the measurement of the combined drugs native fluorescence after excitation at 270 nm in methanol directly, followed by differentiation using first (D1) and second derivative (D2) techniques. Applying the D1, IBU was measured quantitatively at 293.1 nm at zero crossing of PHE, on the other side; PHE was measured quantitatively at 300.7 nm at zero crossing of IBU. By the same way, applying the D2, the wavelengths selected were 303.5 nm for IBU and 312.9 nm for PHE. The concentration plots of derivative fluorescence intensity were rectilinear over the range of 0.5- 10 μg/mL and 0.025- 0.5 μg/mL for IBU and PHE, respectively. The results obtained with average % recoveries ± RSD are 99.73 ± 0.72 (IBU, D1), 99.49 ± 0.95 (PHE, D1), 99.79 ± 0.47 (IBU, D2), and 99.88 ± 0.34 (PHE, D2) were in good agreement with the comparison method. The proposed methods offer high sensitivity that enable direct analysis of IBU and PHE in spiked human plasma. The proposed methods were entirely validated in terms of ICH guidelines.
关键词： phenylephrine (PHE),ibuprofen (IBU),spiked plasma,derivative emission,Spectrofluorimetry,tablets
更新于2025-09-11 14:15:04