N-doped carbon materials are considered as next-generation oxygen reduction reaction (ORR) catalysts for fuel cells due to their prolonged stability and low cost. However, the underlying mechanism of these catalysts has been only insufficiently identified, preventing the rational design of high-performing catalysts. Here, we show that the first electron is transferred into O2 molecules at the outer Helmholtz plane (ET-OHP) over a long range. This is in sharp contrast to the conventional belief that O2 adsorption must precede the ET step and thus that the active site must possess as good an O2 binding character as that which occurs on metallic catalysts. Based on the ET-OHP mechanism, the location of the electrode potential dominantly characterizes the ORR activity. Accordingly, we demonstrate that the electrode potential can be elevated by reducing the graphene size and/or including metal impurities, thereby enhancing the ORR activity, which can be transferred into single-cell operations with superior stability.

Long range electron transfer over graphene-based catalyst for high performing oxygen reduction reactions: Importance of size, N-doping, and metallic impurities

To make methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) more efficient, it is essential to explore Pt support (low Pt-loading) with desirable co-catalytic activity. Herein, tungsten carbide/tungsten oxide/zeolitic imidazolate framework-8 (ZIF-8)-derived carbon ((WC)/W24O68/NCZ8) composites are prepared as Pt-supports/co-catalysts. Heating temperature is controlled to adjust structure and crystalline phases of (WC)/W24O68/NCZ8. For MOR, mass activity (2492.2 mA mg−1Pt) of Pt-WC/W24O68/NCZ8 (850 °C, 5.0 wt.%) is much superior to commercial Pt/C (499.2 mA mg−1Pt, 10.0 wt.%). NCZ8-thin-layer facilitates carburization of W atoms (W24O68 to WC) to form WC/W24O68 heterojunctions. Oxygen vacancies on W24O68 fascinate H+ to encourage formation of tungsten bronze compounds (HyWO3, (0

ZIF-8-derived carbon-thin-layer protected WC/W24O68 micro-sized rods with enriched oxygen vacancies as efficient Pt co-catalysts for methanol oxidation and oxygen reduction

Cu-metal-organic framework supported on chitosan for efficient condensation of aromatic aldehydes and malononitrile.

The large-scale application of clean electrochemical storage and conversion devices such as water splitting and Zn-air batteries greatly depends on the development of low cost and highly efficient electrocatalysts. Transitional...

Current progress of metal sulfides derived from metal organic frameworks for advanced electrocatalysis: potential electrocatalysts with diverse applications

MOF-derived Metal Sulfides for Electrochemical Energy Applications

Synthesis of metal-organic framework-derived cobalt disulfide with high-performance oxygen reduction reaction catalytic properties

Efficient nitrogen-doped porous carbon/carbon nanotube-supported Co3O4/Co catalysts for oxygen reduction reactions in alkaline media

Background The COVID-19 pandemic has a serious impact on the mental health of the public due to its economic and social impact. And psychological effects have led to drug and alcohol abuse. After the city lifted the lockdown, we consecutively encountered several young nitrous oxide abusers admitted to hospital for neurological treatment. Purpose To inform physician decisions and social intervention, this observational study aimed at investigating the neurological and psychological characteristics of nitrous oxide abusers and its underlying causes during the COVID-19 lockdown. Methods The nitrous oxide abusers who sought neurological treatment at our hospital between May 2020 and June 2020 were enrolled. Clinical data including socio-demographic, physical examination, laboratory examination, electromyography and neuroimaging were collected. Their motivations for inhaling nitrous oxide, knowledge about the nitrous oxide abuse and the accompanying of family were investigated face to face. Psychological status was assessed by the Symptom Checklist 90 (SCL-90) psychological evaluation. Results Six nitrous oxide abusers were enrolled and the age was 22 ± 4.3. Clinical presentations included varying degrees of limb numbness and an ataxic gait. Laboratory examination revealed that all the patients did not have pernicious anemia, 4 patients had decreased vitamin B12 while 3 patients exhibited elevated homocysteine levels. MR of the spinal cord revealed that 4 patients had abnormal signals in the cervical spinal cord of high symmetry with splayed or inverted V sign after T2WI. Electromyogram (EMG) test showed 5 patients had peripheral nerve damage. The SCL-90 psychological evaluation results indicated that all patients had severe anxiety, depression and psychosis and they had severer psychological problems than ordinary citizens. Their motives for inhaling nitrous oxide are to relieve boredom, curiosity and buddy pressure. Their family spent <1 day per week to stay with them during city lockdown. Conclusion The enrolled patients caused by abuse of nitrous oxide presented with symptoms of subacute combined with spinal degeneration. They had more serious psychological problems related to the COVID-19 pandemic. These cases make us value the psychological problems of young people under the outbreak and take multi-layered measures from families, schools (companies), hospitals, and governments to address it.

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Neurological and Psychological Characteristics of Young Nitrous Oxide Abusers and Its Underlying Causes During the COVID-19 Lockdown

The invention discloses a novel nano-composite catalyst applied to oxygen reduction and a preparation method thereof. In a process for preparing the catalyst CoFe2O4@CNR, a method for preparing a metal organic-framework precursor material (Fe2Co-MOF) with a controllable size and a bi-metal coordination center is further provided, and the influence of factors such as the dosage of a coordination regulator-sodium acetate, an addition ratio of DMF to water in a mixed solvent and the like on the morphology and the size of the precursor Fe2Co-MOF is researched. The method comprises the following specific steps: taking terephthalic acid as a ligand and cobalt acetylacetonate and anhydrous ferric chloride as a metal cobalt source and an iron source, adjusting the morphology by controlling the dosage of the water in sodium acetate trihydrate and the solvent, and preparing the Fe2Co-MOF through a simple hydrothermal reaction at 110 DEG C; and according to a preferred scheme, taking the Fe2Co-MOF as a template, heating to 600 DEG C at a heating rate of 2 DEG C min , keeping the temperature for 4 hours in a nitrogen atmosphere, and then performing low-temperature oxidation for 3 hours at 300 DEG C in an air atmosphere to prepare the novel nano-composite catalyst applied to the catalytic oxygen reduction. The catalyst has potential application values in the fields of energy conversion and storage.

Novel nano-composite catalyst applied to oxygen reduction and preparation method thereof

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Changqian Feng

Papers

Synthesis of metal-organic framework-derived cobalt disulfide with high-performance oxygen reduction reaction catalytic properties

Efficient nitrogen-doped porous carbon/carbon nanotube-supported Co3O4/Co catalysts for oxygen reduction reactions in alkaline media

Neurological and Psychological Characteristics of Young Nitrous Oxide Abusers and Its Underlying Causes During the COVID-19 Lockdown

Novel nano-composite catalyst applied to oxygen reduction and preparation method thereof

Microscopy Study of the Morphology of Carbonized ZIF-67 Tailored by CTAB