TRPM4-Inspired Polymeric Nanochannels with Preferential Cation Transport for High-Efficiency Salinity-Gradient Energy Conversion.

Biological ion channels exhibit switchable cation transport with ultrahigh selectivity for efficient energy conversion, such as Ca2+-activated TRPM4 channels tuned by cation-π interactions, but achieving an analogous highly selective function is challenging in artificial nanochannels. Here, we design a TRPM4-inspired cation-selective nanochannel (CN) assembled by two poly(ether sulfone)s, respectively, with sulfonate acid and indole moieties, which act as cation-selective activators to manage Na+/Cl- selectivity via ionic and cation-π interactions. The cation selectivity of CNs can be activated by Na+, and thereby the Na+ transference number significantly improves from 0.720 to 0.982 (Na+/Cl- selectivity ratio from 2.6 to 54.6) under a 50-fold salinity gradient, surpassing the K+ transference number (0.886) and Li+ transference number (0.900). The TRPM4-inspired nanochannel membrane enabled a maximum output power density of 5.7 W m-2 for salinity-gradient power harvesting. Moreover, a record energy conversion efficiency of up to 46.5% is provided, superior to most nanochannel membranes (below 30%). This work proposes a novel strategy to biomimetic nanochannels for highly selective cation transport and high-efficiency salinity-gradient energy conversion.

Efficient Pt/KFI zeolite catalysts for the selective catalytic reduction of NOx by hydrogen.

Aiming at purification of NOx from hydrogen internal combustion engines (HICEs), the hydrogen selective catalytic reduction (H2-SCR) reaction was investigated over a series of Pt/KFI zeolite catalysts. H2 can readily reduce NOx to N2 and N2O while O2 inhibited the deNOx efficiency by consuming the reductant H2. The Pt/KFI zeolite catalysts with Pt loading below 0.1 wt.% are optimized H2-SCR catalysts due to its suitable operation temperature window since high Pt loading favors the H2-O2 reaction which lead to the insufficient of reactants. Compared to metal Pt0 species, Ptδ+ species showed lower activation energy of H2-SCR reaction and thought to be as reasonable active sites. Further, Eley-Rideal (E-R) reaction mechanism was proposed as evidenced by the reaction orders in kinetic studies. Last, the optimized reactor was designed with hybrid Pt/KFI catalysts with various Pt loading which achieve a high NOx conversion in a wide temperature range.

Design of Ca-type todorokite catalysts with highly active for the selective reduction of NOx by NH3 at low temperatures.

Ca-type todorokite catalysts were designed and prepared by a simple redox method and applied to the selective reduction of NOx by NH3 (NH3-SCR) for the first time. Compared with the Na-type manjiroite prepared by the same method, the todorokite catalysts with different Mn/Ca ratios showed greatly improved catalytic activity for NOx reduction. Among them, Mn8Ca4 catalyst exhibited the best NH3-SCR performance, achieving 90% NOx conversion within temperature range of 70-275°C and having a high sulphur resistance. Compared to the Na-type manjiroite sample, Ca-type todorokite catalysts possessed an increased size of tunnel, resulting in a larger specific surface area. As increased the amounts of Ca doping, the Na content in Ca-type todorokite catalysts significantly decreased, providing larger amounts of Brønsted acid sites for NH3 adsorption to produce NH4+. The NH4+ species were highly active for reaction with NO + O2, playing a determining role in NH3-SCR process at low temperatures. Meanwhile, larger amounts of surface adsorbed oxygen contained over the Ca-doping samples than that over Na-type manjiroite, promoting the oxidation of NO and fast SCR processes. Over the Ca-type todorokite catalysts, furthermore, nitrates produced during the flow of NO + O2, were more active for reaction with NH3 than that over Na-type manjiroite, benefiting the occurrence of NH3-SCR process. This study provides novel insights into the design of NH3-SCR catalysts with high performance.

Hydrothermal Aging Alleviates the Phosphorus Poisoning of Cu-SSZ-39 Catalysts for NH3-SCR Reaction.

As a new type of catalyst with the potential for commercial application in NOx removal from diesel engine exhausts, Cu-SSZ-39 catalysts must have excellent resistance to complex and harsh conditions. In this paper, the effects of phosphorus on Cu-SSZ-39 catalysts before and after hydrothermal aging treatment were investigated. Compared with fresh Cu-SSZ-39 catalysts, phosphorus poisoning significantly decreased the low-temperature NH3-SCR catalytic activity. However, such activity loss was alleviated by further hydrothermal aging treatment. To reveal the reason for this interesting result, a variety of characterization techniques including NMR, H2-TPR, X-ray photoelectron spectroscopy, NH3-TPD, and in situ DRIFTS measurements were employed. It was found that Cu-P species produced by phosphorus poisoning decreased the redox ability of active copper species, resulting in the observed low-temperature deactivation. After hydrothermal aging treatment, however, Cu-P species partly decomposed with the formation of active CuOx species and a release of active copper species. As a result, the low-temperature NH3-SCR catalytic activity of Cu-SSZ-39 catalysts was recovered.

Hydrothermal Stability of CeO2-WO3-ZrO2 Mixed Oxides for Selective Catalytic Reduction of NOx by NH3.

CeO2-WO3-ZrO2 mixed oxides were prepared by the homogeneous precipitation method for the selective catalytic reduction of NOx with NH3 (NH3-SCR). The effects of hydrothermal aging on the catalytic performances of CeO2-WO3-ZrO2 were investigated. The results showed that CeO2-WO3-ZrO2 catalyst exhibited excellent NH3-SCR activity for removal of NOx and hydrothermal stability. After hydrothermal aging at 850 °C for 16 h, the optimum CeO2-WO3-ZrO2 catalyst could still realize 80% NOx conversion at 300-500 °C even under a high gas hourly space velocity of 250 000 h-1. The structural properties, redox ability, surface species, and acidity of fresh and hydrothermally aged CeO2-WO3-ZrO2 catalysts were characterized by N2-physisorption, XRD, Raman, H2-TPR, XPS, NH3-TPD, and in situ DRIFTS. The characterization results showed that decreases of 89% of the surface area and 71% of the NH3 storage capacity as well as new phase formation occurred for the CeO2-WO3-ZrO2 sample after hydrothermal aging at 850 °C for 16 h. The activity of hydrothermally aged CeO2-WO3-ZrO2 was mainly attributed to the retention of redox-acid sites and their interaction due to the formation of Ce-Zr solid solutions and Ce4W9O33.

Alkali resistance promotion of Ce-doped vanadium-titanic-based NH3-SCR catalysts.

The effect of K deactivation on V2O5/WO3-TiO2 and Ce-doped V2O5/WO3-TiO2 catalysts in the selective catalytic reduction (SCR) of NOx by NH3 was studied. Ce-doped V2O5/WO3-TiO2 showed significantly higher resistance to K deactivation than V2O5/WO3-TiO2. Ce-doped V2O5/WO3-TiO2 with K/V=4 (molar ratio) showed 90% NOx conversion at 350°C, whereas in this case V2O5/WO3-TiO2 showed no activity. The fresh and K-poisoned V2O5/WO3-TiO2 and Ce-doped V2O5/WO3-TiO2 catalysts were investigated by means of in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), NH3-temperature progress decomposition (NH3-TPD), X-ray photoelectron spectroscopy (XPS) and H2-temperature program reduction (H2-TPR). The effect of Ce doping on the improving resistance to K of V2O5/WO3-TiO2were discussed.

[Human tau N-terminal domain-specific monoclonal antibodies: screening and application in blood detection].

The antibodies to the microtubule-associated protein tau play a role in basic and clinical studies of Alzheimer's disease (AD) and other tauopathies. With the recombinant human tau441 as the immunogen, the hybridoma cell strains secreting the anti-human tau N-terminal domain (NTD-tau) monoclonal antibodies were generated by cell fusion and screened by limiting dilution. The purified monoclonal antibodies were obtained by inducing the mouse ascites and affinity chromatography. The sensitivity and specificity of the monoclonal antibodies were examined by indirect ELISA and Western blotting, respectively. A double antibody sandwich ELISA method for detecting human tau protein was established and optimized. The results showed that the positive cloning rate of hybridoma cells was 83.6%. A stable cell line producing ZD8F7 antibodies was established, and the antibody titer in the supernatant of the cell line was 1:16 000. The antibody titer in the ascitic fluid was higher than 1:256 000; and the titer of purified ZD8F7 monoclonal antibodies was higher than 1:128 000. The epitope analysis showed that the ZD8F7 antibody recognized tau21-37 amino acid in the N-terminal domain. The Western blotting results showed that the ZD8F7 antibody recognized the recombinant human tau protein of 50-70 kDa and the human tau protein of 50 kDa in the brain tissue of transgenic AD model mice (APP/PS1/tau). With ZD8F7 as a capture antibody, a quantitative detection method for human tau protein was established, which showed a linear range of 7.8-500.0 pg/mL and could identify human tau protein in the brain tissue of AD transgenic mice and human plasma but not recognize the mouse tau protein. In conclusion, the human NTD-tau-specific monoclonal antibody and the double antibody sandwich ELISA method established in this study are highly sensitive and can serve as a powerful tool for the detection of tau protein in neurodegenerative diseases.

Influence of Mn on the iron-based friction material directly prepared by in situ carbothermic reaction from vanadium-bearing titanomagnetite concentrates.

In this work, we prepared an iron-based frictional material from vanadium-bearing titanomagnetite concentrates by in situ carbothermic reaction with improved tribological properties. Effects of Mn content (1-4 wt%) on the microstructure and properties of iron-based friction material were investigated. The microstructure and properties of iron-based friction material with Mn are significantly improved. In particular, the friction coefficient decreases from 0.54 to 0.40-0.49 and the wear rate reduces from 1.899 × 10-7 cm3 J-1 to 0.229 × 10-7 cm3 J-1 - 1.309 × 10-7 cm3 J-1. Appropriate Mn addition (1-3 wt%) contributes efficiently to the sintering densification and increasing laminated pearlites. Comparatively, the density, hardness and wear resistance are improved. The dominant wear mechanism changes from severe abrasive wear to mild abrasive wear and oxidative wear is also enhanced. However, when Mn content increases to 4 wt%, the microstructure, relative density, hardness and wear performance of iron-based friction material are deteriorated. Consequently, the optimal addition of Mn is 3 wt% in the iron-based friction material.

Polymeric vanadyl species determine the low-temperature activity of V-based catalysts for the SCR of NO x with NH3.

The structure of dispersed vanadyl species plays a crucial role in the selective catalytic reduction (SCR) of NO with NH3 over vanadia-based catalysts. Here, we demonstrate that the polymeric vanadyl species have a markedly higher NH3-SCR activity than the monomeric vanadyl species. The coupling effect of the polymeric structure not only shortens the reaction pathway for the regeneration of redox sites but also substantially reduces the overall reaction barrier of the catalytic cycle. Therefore, it is the polymeric vanadyl species, rather than the monomeric vanadyl species, that determine the NH3-SCR activity of vanadia-based catalysts, especially under low-temperature conditions. The polymeric vanadia-based SCR mechanism reported here advances the understanding of the working principle of vanadia-based catalysts and paves the way toward the development of low vanadium-loading SCR catalysts with excellent low-temperature activity.