Synthesis and Characterization of Cobalt and Nitrogen Co Doped Peat Derived Carbon Catalysts for Oxygen Reduction in Acidic Media

In this study, several peat derived carbons PDC were synthesized using various carbonization protocols. It was found that depending on the carbonization method, carbons with very different surface morphologies, elemental compositions, porosities, and oxygen reduction reaction ORR activities were obtained. Five carbons were used as carbon supports to synthesize Co N PDC catalysts, and five different ORR catalysts were acquired. The surface analysis revealed that a higher nitrogen content, number of surface oxide defects, and higher specific surface area lead to higher ORR activity of the Co N PDC catalysts in acidic solution. The catalyst Co N C 2 ZnCl2 , which was synthesized from ZnCl2 activated and pyrolyzed peat, showed the highest ORR activity in both rotating disk electrode and polymer electrolyte membrane fuel cell tests. A maximum power density value of 210 mW cm2 has been obtained. The results of this study indicate that PDCs are promising candidates for the synthesis of active non platinum group metal type catalyst

Common Nodes of Virus-Host Interaction Revealed Through an Integrated Network Analysis

Viruses are one of the major causes of acute and chronic infectious diseases and thus a major contributor to the global burden of disease. Several studies have shown how viruses have evolved to hijack basic cellular pathways and evade innate immune response by modulating key host factors and signaling pathways. A collective view of these multiple studies could advance our understanding of virus-host interactions and provide new therapeutic perspectives for the treatment of viral diseases. Here, we performed an integrative meta-analysis to elucidate the 17 different host-virus interactomes. Network and bioinformatics analyses showed how viruses with small genomes efficiently achieve the maximal effect by targeting multifunctional and highly connected host proteins with a high occurrence of disordered regions. We also identified the core cellular process subnetworks that are targeted by all the viruses. Integration with functional RNA interference (RNAi) datasets showed that a large proportion of the targets are required for viral replication. Furthermore, we performed an interactome-informed drug re-purposing screen and identified novel activities for broad-spectrum antiviral agents against hepatitis C virus and human metapneumovirus. Altogether, these orthogonal datasets could serve as a platform for hypothesis generation and follow-up studies to broaden our understanding of the viral evasion landscape.Peer reviewe

Fe-N/C catalysts for oxygen reduction based on silicon carbide derived carbon

Two different Fe-N/C(SiC) catalysts (Fe+Bipyr/C(SiC) and Fe+Phen/C(SiC)) for oxygen reduction based on silicon carbide derived carbon were synthesized and investigated in 0.1M KOH aqueous solution by rotating disc electrode method. It was found that the electrocatalytic activity and stability are significantly influenced by the change of the nitrogen ligand in the catalyst. Comparable current density values obtained for 20%Pt-Vulcan electrode could be achieved for Fe+Bipyr/C(SiC) and Fe+Phen/C(SiC) catalysts in alkaline media. The durability tests (~150h) showed that the decrease of the activity for Fe+Bipyr/C(SiC) and Fe+Phen/C(SiC) is only 0.5mVh−1 and 0.17mVh−1, respectively. The Fe+Bipyr/C(SiC) catalyst demonstrated higher activity in the RDE measurements, but during the long-term test the Fe+Phen/C(SiC) catalyst prove to be more stable than Fe+Bipyr/C(SiC). Keywords: Oxygen reduction reaction, Carbide derived carbon, Fe-N/C catalyst, Rotating disc electrode method, Durability tes

Exploring Different Synthesis Parameters for the Preparation of Metal Nitrogen Carbon Type Oxygen Reduction Catalysts

The influence of various synthesis conditions of a metal nitrogen carbon M N C catalyst material on oxygen reduction reaction ORR kinetics is discussed. Seven M N C catalysts based on cobalt are obtained by changing various synthesis conditions, such as the mixing environment, pyrolysis gas, and post treatment. The ORR activity and stability measurements are performed using the classical three electrode configuration in a 0.1 M HClO4 solution. The most active and stable ORR catalyst proves to be the material obtained by mixing a cobalt salt, 2,2 bipyridine, and a high surface area silicon carbide derived carbon together in water and pyrolyzing the mixture in argon. In a fuel cell test, however, a maximum power density value of 135 mW cm amp; 8722;2 is achieved with the catalyst mixed together in a planetary ball mill at a low catalyst loading of 1.0 0.1 mg cm amp; 8722;2 and at a test cell temperature of 60 oC despite of the fact that preparing the catalyst via dry ball milling reduces the surface area of the material roughly 40 more than in the case of using a solution based method. Consequently, mixing the catalyst precursors together without any additional chemicals in a planetary ball mill instead of in a solution appears to be the most promising choic

Peat derived carbon based non platinum group metal type catalyst for oxygen reduction and evolution reactions

For the first time, a novel peat derived carbon PDC was used to synthesize an active non platinum group metal type catalyst for the oxygen reduction reaction ORR and oxygen evolution reaction OER . The obtained catalyst exhibited a smaller specific surface area and was more graphitic compared to a catalyst synthesized identically but using carbide derived carbon CDC instead of PDC. Due to the organic nature of the used peat, the PDC contained numerous additives. In 0.1 M KOH, both the PDC and CDC based catalysts displayed ORR activity comparable to Pt Vulcan. Additionally, equally high OER activities of 1.59 V vs RHE at 10 mA cm amp; 8722;2 were reached for both catalysts studied. Considering the remarkable bifunctional activity of the PDC based catalyst, it can be concluded that PDC is an exceptionally promising carbon support material for ORR and OER catalyst

Cobalt and Nitrogen Co Doped Peat Derived Carbon Based Catalysts for Oxygen Reduction

Using different carbonization protocols, five peat derived carbon materials were synthesized. These carbons have very different surface morphology confirmed by HR SEM and different porosities and pore size distributions obtained by N2 sorption method. The ORR activity of the peat derived carbons also differs significantly in 0.1 M HClO4 solution. Additionally, co doping the peat derived carbons with cobalt and nitrogen enhanced their catalytic activity considerably. The most active ORR catalyst was achieved using the carbon support where the dry milled peat was mixed with ZnCl2 and pyrolyzed in Ar for 2 h at 700 C. Interestingly, the activity of the initial carbon powder does not seem to be a clear indicator of the final activity of the M N C catalysts synthesized from i

Unlocking the porosity of Fe N C catalysts using hydroxyapatite as a hard template en route to eco friendly high performance AEMFCs

In this work, we propose hydroxyapatite HA as a hard template to unlock the porosity of Fe N C catalyst materials. Using HA, a naturally occurring mineral that can be removed with nitric acid, in the synthesis generates a catalyst material with a unique porous network comprising abundant pores and interparticle cavities ranging from 10 to 3000 nm. Hard templating with HA alongside ZnCl2 as a micropore former results in a Fe N C catalyst based on naturally abundant peat with excellent oxygen reduction activity in alkaline conditions. A half wave potential of 0.87 V vs RHE and a peak power density of 1.06 W cm 2 were achieved in rotating ring disk electrode and anion exchange membrane fuel cell experiments, respectively, rivaling the performance of other state of the art platinum free catalysts presented in the literature. A combined approach of using renewable peat as a carbon source and HA as a hard template offers an environmentally friendly approach to high performance Fe N C catalysts with abundant porosit

Posaconazole inhibits multiple steps of the alphavirus replication cycle.

Repurposing drugs is a promising strategy to identify therapeutic interventions against novel and re-emerging viruses. Posaconazole is an antifungal drug used to treat invasive aspergillosis and candidiasis. Recently, posaconazole and its structural analog, itraconazole were shown to inhibit replication of multiple viruses by modifying intracellular cholesterol homeostasis. Here, we show that posaconazole inhibits replication of the alphaviruses Semliki Forest virus (SFV), Sindbis virus and chikungunya virus with EC50 values ranging from 1.4 μM to 9.5 μM. Posaconazole treatment led to a significant reduction of virus entry in an assay using a temperature-sensitive SFV mutant, but time-of-addition and RNA transfection assays indicated that posaconazole also inhibits post-entry stages of the viral replication cycle. Virus replication in the presence of posaconazole was partially rescued by the addition of exogenous cholesterol. A transferrin uptake assay revealed that posaconazole considerably slowed down cellular endocytosis. A single point mutation in the SFV E2 glycoprotein, H255R, provided partial resistance to posaconazole as well as to methyl-β-cyclodextrin, corroborating the effect of posaconazole on cholesterol and viral entry. Our results indicate that posaconazole inhibits multiple steps of the alphavirus replication cycle and broaden the spectrum of viruses that can be targeted in vitro by posaconazole, which could be further explored as a therapeutic agent against emerging viruses