Recent Progress on Fe/N/C Electrocatalysts for the Oxygen Reduction Reaction in Fuel Cells

In order to reduce the overall system cost, the development of inexpensive, high-performance and durable oxygen reduction reaction (ORR)N, Fe-codoped carbon-based (Fe/N/C) electrocatalysts to replace currently used Pt-based catalysts has become one of the major topics in research on fuel cells. This review paper lays the emphasis on introducing the progress made over the recent five years with a detailed discussion of recent work in the area of Fe/N/C electrocatalysts for ORR and the possible Fe-based active sites. Fe-based materials prepared by simple pyrolysis of transition metal salt, carbon support, and nitrogen-rich small molecule or polymeric compound are mainly reviewed due to their low cost, high performance, long stability and because they are the most promising for replacing currently used Pt-based catalysts in the progress of fuel cell commercialization. Additionally, Fe-base catalysts with small amount of Fe or new structure of Fe/Fe3C encased in carbon layers are presented to analyze the effect of loading and existence form of Fe on the ORR catalytic activity in Fe-base catalyst. The proposed catalytically Fe-centered active sites and reaction mechanisms from various authors are also discussed in detail, which may be useful for the rational design of high-performance, inexpensive, and practical Fe-base ORR catalysts in future development of fuel cells

Highly Efficient Regeneration of Deactivated Au/C Catalyst for 4‑Nitrophenol Reduction

In the present work, we proposed an effective method to regenerate sintered gold catalyst by improving the dispersion of gold nanoparticles. With the liquid oxychlorination reaction, a sintered carbon-supported gold (Au/C) nanocatalyst was effectively regenerated by improving the redispersion of Au nanoparticles with additional carbon support. The Au-catalyzed model reaction between 4-nitrophenol and sodium borohydride (NaBH₄) indicates that the apparent activity of the optimal Au/C regenerated (Au 0.45 wt %) exceeds that of the initial fresh Au/C (Au 1 wt %), making Au utilization tripled and potentially sustainable for their extensive application in industry

Characterization of VOC source profiles, chemical reactivity, and cancer risk associated with petrochemical industry processes in Southeast China

The petrochemical industry is one of the main sources of industrial volatile organic compounds (VOCs) emissions. In this study, typical petrochemical refining enterprises in Southeast China were selected, direct testing of VOCs in 18 petrochemical processes, and 87 samples were obtained using different on-site sampling methods, such as stack, fugitive, static and dynamic sealing point emissions sampling methods, based on the key process units, tank areas, loading and unloading areas, and plant boundaries of the petrochemical industry. Simultaneously, on-site concentration testing and laboratory analysis of 115 VOCs were conducted. Our findings reveal that, although the overall industry emission profile predominantly consists of low-carbon alkanes and alkenes, with relatively minimal halogenated hydrocarbon VOC emissions, there are substantial discrepancies in the primary species across different stages. The mass percentages of alkanes, alkenes, aromatics, halogenated hydrocarbons, and oxygenated VOCs in different process units of the petrochemical industry were 55 ± 27%, 8.5 ± 15%, 23 ± 27%, 3.9 ± 4.3%, and 10 ± 8.4%, respectively. The dominant species in the atmospheric vents of the depropanizer, light hydrocarbon recovery unit, continuous reforming unit, catalytic cracking unit, and sulfur recovery unit were n-butane (15%), n-hexane (13%), propane (21%), propylene (26%), and ethylene (28%), respectively. The dominant species in the gasoline tank top source profile was isopentane (48%), while that of the gasoline loading and unloading area was methyl tert-butyl ether (19%). High-carbon alkanes such as n-decane, n-octane, and n-heptane (>5% mass fractions) were prominent in kerosene tank tops. Furthermore, the results of the chemical reactivity assessment indicate that VOC emissions during the loading and unloading processes, as well as the ethylene production process, should be managed to mitigate ozone formation potential. According to the cancer risk assessments, benzene was the main factor that increased the risk, and its levels were far beyond the accepted cutoff point

Qualification of LSP1-2111 as a Brain Penetrant Group III Metabotropic Glutamate Receptor Orthosteric Agonist

LSP1-2111 is a group III metabotropic glutamate receptor agonist with preference toward the mGlu4 receptor subtype. This compound has been extensively used as a tool to explore the pharmacology of mGlu4 receptor activation in preclinical animal behavioral models. However, the blood–brain barrier penetration of this amino acid derivative has never been studied. We report studies on the central nervous system (CNS) disposition of LSP1-2111 using quantitative microdialysis in rat. Significant unbound concentrations of the drug relative to its <i>in vitro</i> binding affinity and functional potency were established in extracellular fluid (ECF). These findings support the use of LSP1-2111 to study the CNS pharmacology of mGlu4 receptor activation through orthosteric agonist mechanisms

DPIFuzz: A Differential Fuzzing Frameworkto Detect DPI Elusion Strategies for QUIC

QUIC is an emerging transport protocol that has the potential to replace TCP in the near future. As such, QUIC will become an important target for Deep Packet Inspection (DPI). Reliable DPI is essential, e.g., for corporate environments, to monitor traffic entering and leaving their networks. However, elusion strategies threaten the validity of DPI systems, as they allow attackers to carefully design traffic to fool and thus evade on-path DPI systems. While such elusion strategies for TCP are well documented, it is unclear if attackers will be able to elude QUIC-based DPI systems. In this paper, we systematically explore elusion methodologies for QUIC. To this end, we present DPIFuzz: a differential fuzzing framework which can automatically detect strategies to elude stateful DPI systems for QUIC. We use DPIFuzz to generate and mutate QUIC streams in order to compare (and find differences in) the server-side interpretations of five popular open-source QUIC implementations. We show that DPIFuzz successfully reveals DPI elusion strategies, such as using packets with duplicate packet numbers or exploiting the diverging handling of overlapping stream offsets by QUIC implementations. DPIFuzz additionally finds four security-critical vulnerabilities in these QUIC implementations