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Pt single-atom materials possess an ideal atom economy but suffer from limited intrinsic activity and side reaction of producing H

Developing interfacial connections is one of the breakthrough strategies to improve the photocatalytic activity. Herein, ZnBi2O4 nanoparticles-ZnO nanorods heterojunction was successfully synthesized and used, as a dual-function photocatalyst, for photocatalytic degradation of Bisphenol A and hydrogen production with improved photocatalytic activity under simulated sunlight irradiation. The highest H2 production (3.44 mmol g−1 h−1) was obtained for ZnO-20 wt% ZnBi2O4 sample, which is around 12.7 times higher than pure ZnO. According to the HRTEM result, the intimate interfacial connections are formed between ZnO and ZnBi2O4 which could act as trapping centers for charge carriers and results in the boosted photocatalytic activity. Further, a high aspect ratio of 1D ZnO nanorods and small size of 0D ZnBi2O4 nanoparticles (~10 nm) increases the number of interfacial contacts and thus the charge carriers’ recombination was suppressed more efficiently. Based on the trapping experiments, ESR and Mott-Schottky analysis, ZnBi2O4–ZnO hybrid photocatalyst followed the S-scheme charge transfer mechanism.

Ag doped Sn

Surface modification for templated synthesis is crucial to achieving three-dimensional (3D) architectured materials for catalysis, photonics, energy storage, etc. However, the existing facile and versatile modification methods (e.g. with dopamine and catechol) generate modification layers that are unstable in harsh environments. These methods are thus unsuitable for electrical applications. Here we report that Ce4+ can act as an effective surface modification reagent for a broad range of substrates (chitinous butterfly wings, carbon paper, nickel foam, and polyethylene terephthalate planks) with various structural features owing to its strong oxidizing ability and Lewis acid nature. The modification yields discrete CeO2 seed layers on substrate surfaces in ca. 0.25-2 h, important for the subsequent conformal growth of CeO2 nanoparticles, Ni(OH)2 nanowires, FeOOH nanosheets, and WO3 nanosheets into 3D architectured materials. The conformally synthesized FeOOH on nickel foam (NF) yields an overpotential of 241 mV at 10 mA cm-1 for an oxygen evolution reaction. This value is comparable to a typical catalyst Ni(Fe)OOH-NF for which the Ni/Fe ratio must be well-optimized. This facile and versatile strategy might have broad applications in the conformal fabrication and application of 3D architectured materials, especially when applied in electrical applications of architectured materials (e.g. Li-ion battery).

In this project, poly (citric acid) (PCA) functionalized on nano Ag/Cu was synthesized by chemical analysis method. The nano probe was applied to detection of cysteine by using the magnesium (II) ions as a cross linker. The characterization of Ag/Cu/PCA nano probe was studied by using the UV–visible, morphological microscopy, dynamic light scattering, and zeta potential analyzer. The zeta potential and size of Ag/Cu/PCA were -38.0 mV and 18.0 nm, respectively. The prepared nano probe shows rapid response for detection of cysteine. The detection limit of Ag/Cu/PCA nano probe was 0.07 nM. Additional, the Ag/Cu/PCA nanoparticles was applied to cysteine detection from real samples in the presence of amino acids compounds. Rapidly and sensitive determination of Streptococcus pneumoniae is substantial for food safety and human health. The DNA-Ag/Cu/PCA were prepared as a template in chemical method and experimented as a bio-receptor for the cell bacteria detection as peroxidase-like catalytic process. The DNA-Ag/Cu/PCA nano probe shows a linear dynamic concertation range of Streptococcus pneumoniae via detection limit about 65 CFU/mL. The project presents that the DNA-Ag/Cu/PCA could detect the biological and bacterial samples via high accuracy.

Ti-XAl-2Fe-3Cu (X = 2.7, 4 wt%) alloys with a high tensile yield strength of up to 1150 MPa were synthesized using powder compact extrusion from blended TiH2 and elemental powders. The microstructures and mechanical properties of the extruded rods without and with a homogenization heat treatment at 1000 °C for 1 h followed by furnace cooling were investigated. It was found that the Al content and heat treatment had significant effects on the microstructures and mechanical properties. With increasing the Al content from 2.7 to 4 wt%, the average lamellar colony size and lamellar thickness of the as-extruded Ti-XAl-2Fe-3Cu alloy decreased from 442.4 to 224.1 µm and 6.7–5.2 µm respectively. The heat treatment increased the lamellar thickness as well as the level of partitioning of Fe and Cu between α and β phases. As a result of the microstructural changes, increasing Al from 2.7 to 4 wt% caused a slight increase in the strength of Ti-XAl-2Fe-3Cu alloys without changing the ductility, while the heat treatment slightly reduced the strength of the alloys, but clearly increased their tensile ductility. The correlation between microstructures and mechanical properties is discussed.

Ti-XAl-2Fe-3Cu (wt%) (X = 2.7,4) alloys were fabricated by extrusion of compacts of TiH2/Al/Fe/Cu powder blends. The microstructure and compressive and biocorrosion properties of the as-extruded rods were studied and compared to those of commercial pure (CP) Ti fabricated by extrusion of a TiH2 powder compact under the same condition. The results show that the Ti-XAl-2Fe-3Cu alloy samples exhibit a significantly higher hardness and compressive yield strength than the CP Ti sample, and with increasing the Al content from 2.7 to 4 wt%, the compressive yield strength of the alloy increases from 1315 to 1422 MPa. The Ti-XAl-2Fe-3Cu alloy samples possess a better biocorrosion resistance than CP Ti, and the polarization resistance of the alloy increases with increasing Al content due to the reduced diffusion rate of corrosive ions through the surface oxide layers. Furthermore, with increasing the immersion time, the polarization resistance increases, and the double layer capacitance decreases. Overall the alloys show significantly better compressive strength and biocorrosion resistance than CP Ti, suggesting that they are more favorable than CP Ti for biomedical applications.

In this work, hierarchical WO3-CeO2 hollow sphere heterojunctions were fabricated via a two-step hydrothermal method and applied for degradation of sulfamerazine antibiotic under visible light irradiation. The incorporation of CeO2 into the WO3 microspheres was confirmed by XRD, BET, HRTEM, and XPS analysis. The results revealed that the photocatalytic activity of WO3-CeO2 heterojunction was greatly enhanced compared to pure CeO2 and WO3 samples, and the highest degradation percentage of sulfamerazine was achieved on the WO3-CeO2 heterojunction with 30 mol. % CeO2 content. This could be ascribed to the efficient separation of charge carriers which was facilitated by oxygen vacancies formed at the interfaces of two coupled semiconductors. EIS analysis verified that the charge transfer resistance of WO3-30CeO2 heterojunction was decreased, which is due to the heterojunction effect. Moreover, based on the Mott-Schottky calculations, radical trapping experiments and ESR analysis, hydroxide radicals were identified as the main active species, and an S-scheme charge transfer mechanism was suggested to explain the enhanced photocatalytic activity. The possible degradation pathway of sulfamerazine was suggested through the detection of degradation intermediates by mass spectroscopy.

In this work, novel Bi2WO6-ZnBi2O4 p-n heterojunction was successfully synthesized through combination of sonochemical and hydrothermal procedures. The results revealed that the sonochemically prepared nanocomposites had spherical shape with amorphous structure which became crystalline particles with flak-like morphology after hydrothermal treatment. Bi2WO6-ZnBi2O4 nanocomposite with 20 wt% ZnBi2O4 content demonstrated the highest photocatalytic performance compared to the pure Bi2WO6 and ZnBi2O4 samples toward the degradation of Malachite Green (MG). This finding is associated with the efficient separation of photo-generated electron/hole pairs due to the formation of interfacial charge transfer between Bi2WO6 and ZnBi2O4. However, further ZnBi2O4 loading had no significant effect on the enhancement of photocatalytic activity of nanocomposite samples owing to the shielding effect of ZnBi2O4 against incident light. The obtained results were further verified by optical and photocurrent density measurements. Based on the obtained results from active species trapping experiments, electron spin resonance and Mott-Schottky calculations, the Z-scheme charge transfer pathway was proposed as the predominant mechanism for the photocatalytic reactions. Also, the photocatalytic degradation of 2,4-dichlorophenol, as a colorless model pollutant, was conducted on optimal composite sample to study the possible contribution of MG dye sensitization mechanism in the enhancement of photocatalytic efficiency.

Sulfide ions are the main toxic material, and can be polluted the environment by different industrial activity wastes. The detection of S2- ions was conducted by a sensitive and selective method in trace levels from aquatic solution. In this study, the silver/iron on graphitic carbon nitride-carrageenan (Ag/Fe/g-C3N4-Carr) nanocomposites was prepared by chemical synthesis method. The Ag/Fe/g-C3N4-Carr sensor was characterized as structural and optical properties via different analysis devices. The main zeta potential and average particle size of Ag/Fe/g-C3N4-Carr was -30.0 mV and 22 nm, respectively. The interaction time of S2- ions detection with the prepared probe is 1.5 min. The limit of detection of S2- ions was 0.6 nM by Ag/Fe/g-C3N4-Carr with good linearity in 20–60 nM of S2- concentration. The degradation of penicillin G (PENG) was conducted by Ag/Fe/g-C3N4-Carr catalyst under UV light irradiation. The degradation amount of PENG was 99.42% under UV light irradiation in 25 min. The Ag/Fe/g-C3N4-Carr particles depicted the best bactericidal activities.

The Ag doped CoTiO3 (Ag-CTO) and Ag doped CoTiO3/Chitosan–amylopectin (Ag-CTO/CSAP) were prepared using hydrothermal method for photocatalysis under sunlight irradiation. The optical and morphological properties were studied by different analysis devices. Optical analysis shows a reduction in the band-gap energy of Ag-CTO/CSAP nanocomposites. Photocatalytic activity of the Ag-CTO and Ag-CTO/CSAP was studied. The Ag-CTO/CSAP nanocomposites gained the highest catalytic activity (96.74%) for degradation of Crystal-Violet (CV) dye as an organic dye pollutant under sunlight irradiation in 40 min. This improvement could be due to high surface area, the hybrid effect of the adsorption-degradation process, and decreasing the band-gap energy. Therewith, the Ag-CTO/CSAP nanocomposites have substantial bactericidal and fungicidal properties against P. aeruginosa, S. pneumoniae, A. niger, and C. albicans.

In this project, the Au and Ce co-doped SnS2 decoration on hyperbranched polyethyleneimine (Au/Ce/SnS2/HPEI) nanocomposites were prepared via wet/hydrothermal chemical method. Compared with pure SnS2 and co doped SnS2, Au/Ce/SnS2/HPEI nanocomposite indicated higher photo-degradation performance for the reduction of chromium (VI) under visible light irradiation. Therewith, Au/Ce/SnS2/HPEI nanocomposites was applied for photo-degradation of drug. The possible mechanism shows the superoxide anion radical ( O2−) plays important role in in the removal of Cr(VI). The Au/Ce/SnS2/HPEI nanocomposites shows the best photocatalysis activity for water reduction. The prepared Au/Ce/SnS2/HPEI displayed excellent antifungal activity against Aspergillus niger and Candida albicans fungi.

Surface modification for templated synthesis is crucial to achieving three-dimensional (3D) architectured materials for catalysis, photonics, energy storage, etc. However, the existing facile and versatile modification methods (e.g. with dopamine and catechol) generate modification layers that are unstable in harsh environments. These methods are thus unsuitable for electrical applications. Here we report that Ce4+ can act as an effective surface modification reagent for a broad range of substrates (chitinous butterfly wings, carbon paper, nickel foam, and polyethylene terephthalate planks) with various structural features owing to its strong oxidizing ability and Lewis acid nature. The modification yields discrete CeO2 seed layers on substrate surfaces in ca. 0.25-2 h, important for the subsequent conformal growth of CeO2 nanoparticles, Ni(OH)2 nanowires, FeOOH nanosheets, and WO3 nanosheets into 3D architectured materials. The conformally synthesized FeOOH on nickel foam (NF) yields an overpotential of 241 mV at 10 mA cm-1 for an oxygen evolution reaction. This value is comparable to a typical catalyst Ni(Fe)OOH-NF for which the Ni/Fe ratio must be well-optimized. This facile and versatile strategy might have broad applications in the conformal fabrication and application of 3D architectured materials, especially when applied in electrical applications of architectured materials (e.g. Li-ion battery).

In this project, Sn-Fe bimetallic nanoparticles were prepared by a facile method. The bimetallic nanoparticles of it could be well established by a field emission scanning electron microscope micrographs. Due to the excellent synergistic influence between Sn-Fe nanoparticles and leucine indicated a great performance for determination of Cr3+. The material was characterized using the XRD, DLS, and zetasizer for the evaluation of crystal structure and morphology information. The potential and effective size of Sn-Fe NPs was −29.10 mV and 30 nm, respectively. Cr3+ ions interaction with the Sn-Fe NPs-leucine probe was carried out in 1 min as response time. The limit of detection of Sn-Fe NPs for Cr(III) colorimetric method was 0.25 nM. The prepared nanoparticles showed impressive photocatalysis efficiency for degradation of MO was about 95.1% in 35 min, thus the prepared nanoparticles may be developed for the detoxification of pollution. The prepared nanoparticles depicted effective antibacterial activity against C. botulinum and, H. pylori bacteria.

The catalysis of hydrogen oxidation reaction (HOR) at the anode is one of the most important topics in achieving high-performance proton exchange membrane fuel cells, especially in the presence of hydrogen fuel impurities and during the start-up/shutdown cycling and cell reversal. To improve catalytic HOR performance, Iridium-Ruthenium alloy (IrRu) catalysts have been explored to address the issues. For fundamental understanding of the catalytic HOR activities, this paper employs density functional theory (DFT) calculations to elucidate and interpret the surface modifications and Ru content effect on hydrogen adsorption energy of the IrRu alloys. The catalytic HOR activity trend of the alloyed IrRu catalysts is calculated to be Ir3Ru > IrRu > IrRu3, which is opposite to that experimentally observed. However, if the surface enrichment of Ir atoms on the IrRu surfaces to form core-shell type catalysts, the calculated trend becomes to IrRu3 > IrRu > Ir3Ru, which is in agreement with the experiment result. In spite of higher surface energy on IrRu3 core-shell surface, the compelling d-band downshift can attribute to the surface charge depletion, decreasing hydrogen adsorption energy, and resulting in the highest catalytic activity. For Ir3Ru core-shell catalyst, a relatively higher charge accumulation on the surface Ir is observed, which can up-shift the d-band and increase hydrogen adsorption, resulting the lowest catalytic activity. The IrRu catalyst has intermediate d-band downshift and hydrogen adsorption energy so that its catalytic activity remains between IrRu3 and Ir3Ru for both alloyed and core-shell structures.