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Nitrogen doped graphitic carbon ribbons are prepared by simultaneously graphitization and nitrogen doping of nano crystalline cellulose at high temperature. Ferrous salt works as catalyst for graphitization, without which amorphous carbon is resulted. The graphitic carbon ribbons and amorphous carbon are compared in detail in morphology, crystalline structure, defects, nitrogen groups and ORR activity by means of SEM, TEM, Raman, XRD, XPS and electrochemical characterizations. It is found the nitrogen doped graphitic carbon ribbons has comparable ORR activity with Pt/C catalyst in alkaline medium, which is much better than nitrogen doped amorphous carbon. The improved ORR activity is ascribed to the nitrogen group introduced by NH 3 treatment of graphitic carbon. The as prepared material can work as efficient non noble metal catalyst for the oxygen reduction reaction. [ABSTRACT FROM AUTHOR]

Molybdenum carbide materials have demonstrated remarkable potential in catalyzing the hydrogen evolution reaction (HER). However, further modulation of their performance through simultaneously engineering the size and surface crystal facets remains challenging. Herein, we report the successful fabrication of N-doped carbon-supported monodisperse Mo 2 C nanoparticles with a size of ∼2.06 nm, exhibiting co-exposed (101)/(102) facets-heterojunction, derived from annealing glycine and ammonium molybdate tetrahydrate. The optimized Mo 2 C/NC-Amt catalyst exhibits a low overpotentials of 128 mV to achieve the current density of 10 mA cm−2 and a small Tafel slope of 72 mV dec−1 under alkaline solution. By changing the molybdate precursor, the phase and crystal facet composition of molybdenum carbide can be effectively tuned, which provides a good platform for studying their structure-activity in HER. The theoretical calculations reveal the synergistic effect of (101)/(102) facets-heterojunction accelerates electron transfer and regulates the d band center of Mo 2 C, reducing the reaction barriers of intermediates in the HER process, thus significantly boosting reaction activity. This work proposes a novel insight into the rational fabrication of efficient HER catalysts through facet engineering toward heterojunction construction under the 2.5 nm region. [Display omitted] • Monodisperse Mo 2 C nanoparticles (∼2.06 nm) on N-doped carbon are synthesized. • The formed surface heterojunction involves (101) and (102) facets of Mo 2 C. • DFT calculations reveal the synergistic mechanisms of the facet heterojunctions. • The optimized catalyst presents distinguished HER performance in 1 M KOH. [ABSTRACT FROM AUTHOR]

TiO 2 /ZrO 2 ceramic nanofiltration membranes are successfully fabricated through the polymeric sol–gel route followed by the dip-coating technique. Disk type α-alumina supported mesoporous γ-alumina (pore size: 5–6 nm) is employed as the support in dip-coating. The unsupported and supported composite ceramic membranes are systematically characterized and evaluated in terms of phase composition, chemical stability, gas adsorption, molecular weight cut-off (MWCO), membrane pore size, water flux and salt rejection. It is found that the TiO 2 /ZrO 2 ceramic membranes have amorphous phase at 400 and 500 °C, suggesting the high thermal stability. The fabricated membranes have the MWCO of 620–860 Da, corresponding to the membrane pore size of 1.2–1.5 nm. Relatively low water permeability can be attributed to the low microporosity of the membrane. Donnan exclusion is the dominant transport mechanism of the NF membrane in the single-component system, and salt rejection is closely related to the hydration properties of the ions (e.g., the hydration radius). [ABSTRACT FROM AUTHOR]

We report on a highly active and stable FeNC non noble metal catalyst for the oxygen reduction reaction in alkaline solution. To prepare the FeNC non noble metal catalyst graphitic carbon nitride (g-C 3 N 4 ) and FeCl 3 are used as nitrogen and iron source, respectively. Iron is proved essential for the high catalyst activity. The best catalyst shows similar onset potential with commercial Pt/C catalyst in alkaline solution. The paper reveals whether the Fe 4 N composite is active in the oxygen reduction reaction. The as prepared catalysts show excellent stability with no change in activity after 10,000 cycles of acceleration test. The stability is explained by the protection effect of layers of graphitic carbon on the surface. The as prepared catalyst catalyzes the ORR via a four electron process with similar kinetics to that of Pt/C. The high activity and stability make this catalyst good candidate in alkaline fuel cell and metal air batteries. [ABSTRACT FROM AUTHOR]

A non metal catalyst for the oxygen reduction reaction is prepared by simply pyrolyzing ion exchange resin D113 in NH 3 . The product is nitrogen doped amorphous carbon. The pyrolysis of D113 exchanged with iron ion results in nitrogen doped graphitic carbon. The amorphous carbon is easier to be doped by NH 3 with higher nitrogen content. The nitrogen doped amorphous carbon is more active than graphitized carbon, together with much improved stability. The higher activity is explained by the higher total nitrogen content and higher pyridinic/graphitic nitrogen percentage. The higher stability is because there is no loss or dissolution of the active sites. The results of this work prove metal element and graphitization of carbon are not necessary factors for nitrogen doped carbon as non noble metal catalyst for the oxygen reduction reaction. [ABSTRACT FROM AUTHOR]

The nitrogen doping effect on a kind of graphitic carbon as non noble metal catalyst for the oxygen reduction reaction is studied. Glycine and NH 3 are chosen as different nitrogen source and different doping sequences are applied. The structural defect of graphitic carbon, total nitrogen content, types of nitrogen species and surface area are different from different treatment. Glycine will not influence the structure of graphitic carbon but NH 3 introduces defects. Glycine introduces high content of nitrogen to graphitic carbon but NH 3 introduces no nitrogen. The best catalyst is prepared by doping graphitic carbon with glycine first then heat treated with NH 3 . Some of the nitrogen species can be removed by further NH 3 treatment, but the relative content of graphitic nitrogen increases, together with increased surface area result in higher activity. [ABSTRACT FROM AUTHOR]

Nitrogen doped carbon material works as non-noble-metal catalyst for the oxygen reduction reaction. In this work the doping effect on two different carbon material by two different nitrogen sources is studied. The carbon material studied is self-prepared carbon ribbon with higher graphitization degree compared with commercial Vulcan XC72 carbon powder. NH 3 and glycine are used as nitrogen sources which produce nitrogen containing functionalities after high temperature pyrolysis. NH 3 doping of carbon ribbon has no positive effect on the ORR activity, while an obvious increase in the activity is found for the glycine doped carbon ribbon. The NH 3 and glycine doped Vulcan carbon show similar activities which are better than undoped Vulcan carbon. The difference is explained by graphitization degree, nitrogen content and type of nitrogen containing functionalities. [ABSTRACT FROM AUTHOR]

I-doped graphene is synthesized by a facile heat treatment method and used as anode material for lithium ion battery. The doped graphene exhibits high reversible capacity (1690 mAh g −1 at 100 mA g −1 ), good cyclability (retaining 92.6% reversible capacity after 200 cycles) and excellent rate performance compared with undoped graphene. The superior electrochemical performance of the I-doped graphene is explained by the change of graphene lattice, defects and positive charge density introduced by the doping of I atoms. [ABSTRACT FROM AUTHOR]

• Provided accurate genome and annotation data of Russula griseocarnosa firstly. • Clarified that non-correlation between taxonomy and nutritional ecological type. • Screened out the specific carbohydrate enzymes in R. griseocarnosa. Russula griseocarnosa is a well-known ectomycorrhizal mushroom, which is mainly distributed in the Southern China. Although several scholars have attempted to isolate and cultivate fungal strains, no accurate method for culture of artificial fruiting bodies has been presented owing to difficulties associated with mycelium growth on artificial media. Herein, we sequenced R. griseocarnosa genome using the second- and third-generation sequencing technologies, followed by de novo assembly of high-throughput sequencing reads, and GeneMark-ES, BLAST, CAZy, and other databases were utilized for functional gene annotation. We also constructed a phylogenetic tree using different species of fungi, and also conducted comparative genomics analysis of R. griseocarnosa against its four representative species. In addition, we evaluated the accuracy of one already sequenced genome of R. griseocarnosa based on the internal transcribed spacer (ITS) sequencing of that type of species. The assembly process resulted in identification of 230 scaffolds with a total genome size of 50.67 Mbp. The gene prediction showed that R. griseocarnosa genome included 14,229 coding sequences (CDs). In addition, 470 RNAs were predicted with 155 transfer RNAs (tRNAs), 49 ribosomal RNAs (rRNAs), 41 small noncoding RNAs (sRNAs), 42 small nuclear RNAs (snRNAs), and 183 microRNAs (miRNAs). The predicted protein sequences of R. griseocarnosa were analyzed to indicate the existence of carbohydrate-active enzymes (CAZymes), and the results revealed that 153 genes encoded CAZymes, which were distributed in 58 CAZyme families. These enzymes included 78 glycoside hydrolases (GHs), 34 glycosyl transferases (GTs), 30 auxiliary activities (AAs), 2 carbohydrate esterases (CEs), 8 carbohydrate-binding modules (CBMs), and only one polysaccharide lyase (PL). Compared with other fungi, R. griseocarnosa had fewer CAZymes, and the number and distribution of CAZymes were similar to other mycorrhizal fungi, such as Tricholoma matsutake and Suillus luteus. Well-defined effector proteins that were associated with mycorrhiza-induced small-secreted proteins (MiSSPs) were not found in R. griseocarnosa , which indicated that there may be some special effector proteins to interact with host plants in R. griseocarnosa. The genome of R. griseocarnosa may provide new insights into the energy metabolism of ectomycorrhizal (ECM) fungi, a reference to study ecosystem and evolutionary diversification of R. griseocarnosa , as well as promoting the study of artificial domestication. [ABSTRACT FROM AUTHOR]