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Iridium-based electrocatalysts remain the only practical anode catalysts for proton exchange membrane (PEM) water electrolysis, due to their excellent stability under acidic oxygen evolution reaction (OER), but are greatly limited by their high cost and low reserves. Here, we report a nickel-stabilized, ruthenium dioxide (Ni-RuO

Atomically ordered intermetallic nanoparticles are promising for catalytic applications but are difficult to produce because the high-temperature annealing required for atom ordering inevitably accelerates metal sintering that leads to larger crystallites. We prepared platinum intermetallics with an average particle size of5 nanometers on porous sulfur-doped carbon supports, on which the strong interaction between platinum and sulfur suppresses metal sintering up to 1000°C. We synthesized intermetallic libraries of small nanoparticles consisting of 46 combinations of platinum with 16 other metal elements and used them to study the dependence of electrocatalytic oxygen-reduction reaction activity on alloy composition and platinum skin strain. The intermetallic libraries are highly mass efficient in proton-exchange-membrane fuel cells and could achieve high activities of 1.3 to 1.8 amperes per milligram of platinum at 0.9 volts.

Supported platinum intermetallic compound catalysts have attracted considerable attention owing to their remarkable activities and durability for the oxygen reduction reaction in proton-exchange membrane fuel cells. However, the synthesis of highly ordered intermetallic compound catalysts remains a challenge owing to the limited understanding of their formation mechanism under high-temperature conditions. In this study, we perform in-situ high-temperature X-ray diffraction studies to investigate the structural evolution in the impregnation synthesis of carbon-supported intermetallic catalysts. We identify the phase-transition-temperature (TPT)-dependent evolution process that involve concurrent (for alloys with high TPT) or separate (for alloys with low TPT) alloying/ordering stages. Accordingly, we realize the synthesis of highly ordered intermetallic catalysts by adopting a separate annealing protocol with a high-temperature alloying stage and a low-temperature ordering stage, which display a high mass activity of 0.96 A mgPt–1 at 0.9 V in H2–O2 fuel cells and a remarkable durability.

It has been widely accepted that Pt is more electrocatalytic than Ru for alkaline hydrogen evolution reactions (HERs), probably on the basis of the previous studies on bulk metals. Herein, we repor...

To investigate whether Hydrolyzed Seawater Pearl tablet (HSPT) could modulate the Th1/Th2 imbalance in an immunosuppressed mouse model with Th1 to Th2 shift induced by Cyclosporine A (CsA) which can be used in the clinical treatment of Th2 to Th1 shift diseases, and explore the possible mechanism for the adjuvant therapeutic efficacy of HSPT on recurrent respiratory infections (RRI) and acquired immune deficiency syndrome (AIDS).The mice were randomly divided into six groups of five animals each, namely normal group, model group, lentinan polysaccharide tablet (LPT) group and three HPST treated groups. HPST treated groups were administered with HPST (0.51, 1.02, 2.04 g/kg) via intragastric gavage (i.g) for 30 consecutive days. LPT used as reference drug for positive control, LPT group was administered with LPT (8.2 mg/kg) for 30 consecutive days. Normal group and model group were received distilled water. The animals in model group, LPT group and HPST treated groups were injected intraperitoneally with CsA (50 mg/kg) to establish the immunosuppressed mice model with Th1 to Th2 shift on the 20th, 22nd and 24th day, one hour after the administration of the respective treatment. Animals were sacrificed one hour after the last administration to collect blood and splenic tissue. The proportion of T cells including CD8+ and CD4+ T cells, Th1 and Th2 in peripheral blood of experimental mice were measured by flow cytometric. The protein level in serum and mRNA level in splenic tissue of experimental mice for interleukin (IL)-2, IL-12, interferon-γ (IFN-γ), IL-4, IL-6, IL-10 and IL-13 were measured by enzyme linked immunosorbent assay and fluorescence quantitative polymerase chain reaction respectively.HSPT elevated the proportion of T cells including both CD8+ and CD4+ T cells, in which the proportion of Th1 and Th2 cells increased, while the ratio of Th1/Th2 cells decreased in peripheral blood of the immunosuppressed mouse model with Th1 to Th2 shift induced by CsA. Furthermore, HSPT elevated both protein and mRNA level of Th1-type cytokines IL-2 and IFN-γ, while had no significant effect on protein and mRNA level of Th1-type cytokine IL-12 and Th2-type cytokines IL-4, IL-6, IL-10, IL- 13 in mouse model.Our findings suggest that HSPT can increase proportion of T cells including both CD8+ and CD4+ T cells and induce Th2 to Th1 shift in both cells and cytokines, which probably was the mechanism to account for the adjuvant therapeutic efficacy of HSPT on RRI and AIDS.

The development of high-performance non-platinum group metal (non-PGM) catalysts for the oxygen reduction reaction (ORR) is still of significance in promoting the commercialization of proton exchange membrane fuel cells (PEMFCs). In this work, a “hierarchically porous carbon (HPC)-supporting” approach was developed to synthesize highly ORR active Fe–phenanthroline (Fe–phen) derived Fe–Nx–C catalysts. Compared to commercial carbon black supports, utilizing HPCs as carbon supports can not only prevent the formation of inactive iron nanoparticles during pyrolysis but also optimize the porous morphology of the catalysts, which eventually increases the amount of reactant-accessible and atomically dispersed Fe–Nx active sites. The prepared catalyst therefore exhibits a remarkable ORR activity in both half-cells (half-wave potential of 0.80 V in 0.5 M H2SO4) and H2–air PEMFCs (442 mA cm−2 at a working voltage of 0.6 V), making it among the best non-PGM catalysts for PEMFCs.

Nanostructured carbon materials with high porosity and desired chemical functionalities are of immense interest because of their wide application potentials in catalysis, environment, and energy storage. Herein, a top-down templating strategy is presented for the facile synthesis of functional porous carbons, based on the direct carbonization of diverse organic precursors with commercially available metal oxide powders. During the carbonization, the metal oxide powders can evolve into nanoparticles that serve as in situ templates to introduce nanopores in carbons. The porosity and heteroatom doping of the prepared carbon materials can be engineered by varying the organic precursors and/or the metal oxides. It is further demonstrated that the top-down templating strategy is applicable to prepare carbon-based single-atom catalysts with iron-nitrogen sites, which exhibit a high power density of 545 mW cm

Hierarchically porous carbons (HPCs) with multimodal pore systems exhibit great technological potentials, especially in the fields of heterogeneous catalysis, energy storage, and conversion. Here, we establish a simple and general approach to HPCs by carbonization of nonporous coordination polymers that are produced by mixing metal salts with polytopic ligands in alkaline aqueous solutions at room temperature. The proposed approach is applicable to a wide scope of ligand molecules (18 examples), thus affording the synthesized HPCs with high diversity in porosity, morphology, and composition. In particular, the prepared HPCs exhibit high specific surface areas (up to 2647 m2 g-1) and large pore volumes (up to 2.39 cm3 g-1). The HPCs-supported atomically dispersed Fe-Nx catalysts show much-improved fuel cell cathode performance over the micropore-dominated carbon black-supported catalysts, demonstrating the structural superiority of the HPCs for enhancing the mass transport properties.

Sulfur doped in carbon matrix can tether metal atoms to form high-loading atomically dispersed supported metal catalysts., Metals often exhibit robust catalytic activity and specific selectivity when downsized into subnanoscale clusters and even atomic dispersion owing to the high atom utilization and unique electronic properties. However, loading of atomically dispersed metal on solid supports with high metal contents for practical catalytic applications remains a synthetic bottleneck. Here, we report the use of mesoporous sulfur-doped carbons as supports to achieve high-loading atomically dispersed noble metal catalysts. The high sulfur content and large surface area endow the supports with high-density anchor sites for fixing metal atoms via the strong chemical metal-sulfur interactions. By the sulfur-tethering strategy, we synthesize atomically dispersed Ru, Rh, Pd, Ir, and Pt catalysts with high metal loading up to 10 wt %. The prepared Pt and Ir catalysts show 30- and 20-fold higher activity than the commercial Pt/C and Ir/C catalysts for catalyzing formic acid oxidation and quinoline hydrogenation, respectively.

Electrocatalysis of hydrogen evolution reaction (HER) in alkaline media is critical for the practical implementation of economical water-alkali electrolyzers. However, the sluggish water dissociation kinetics even on platinum-based electrocatalysts result in poor hydrogen-production activities. Here we report a structurally ordered Ir3V catalyst for efficiently catalyzing HER in alkaline media. The ordered Ir3V catalyst exhibits a low overpotential of 9.0 mV at 10 mA cm−2 in 1.0 M KOH electrolyte with Ir loading of 19 µg cm−2, corresponding a mass activity of 1200 A gIr−1 at the overpotential of 20 mV, which is 6.7, 9.4, and 3.3 times greater than that of the commercial Pt/C, Ir/C, and disordered Ir3V catalysts. The enhanced HER kinetics is ascribed to the charge redistribution on the ordered Ir3V surface with the maximized number of neighboring bimetallic Ir/V sites compared to the disordered solid solution counterpart, which promotes the water dissociation on the electron-deficient V sites.

A transition metal–assisted carbonization process can convert small organic molecules to functional carbon materials directly., Nanostructured carbon materials with large surface area and desired chemical functionalities have been attracting considerable attention because of their extraordinary physicochemical properties and great application potentials in catalysis, environment, and energy storage. However, the traditional approaches to fabricating these materials rely greatly on complex procedures and specific precursors. We present a simple, effective, and scalable strategy for the synthesis of functional carbon materials by transition metal–assisted carbonization of conventional small organic molecules. We demonstrate that transition metals can promote the thermal stability of molecular precursors and assist the formation of thermally stable polymeric intermediates during the carbonization process, which guarantees the successful preparation of carbons with high yield. The versatility of this synthetic strategy allows easy control of the surface chemical functionality, porosity, and morphology of carbons at the molecular level. Furthermore, the prepared carbons exhibit promising performance in heterogeneous catalysis and electrocatalysis.

To solve the problem of grounding parameters of large hydropower, which is in a special soil environment, we deduced unequal potential calculation formula ,based on the model of unequal potential in ground grid and combined with the boundary element method and node voltage method. Through example calculations, the paper analyzes the impact of the ground grid size, soil resistivity and conductor permeability on unequal potential and proves the accuracy of the results, compared with CDEGS software. This method can be used in grounding calculation and analysis of large hydropower stations.