Direct Synthesis of Nitrogen-Doped Carbon Nanosheets with High Surface Area and Excellent Oxygen Reduction Performance

Graphene-like nitrogen-doped carbon nanosheets (NCN) have become a fascinating carbon-based material for advanced energy storage and conversion devices, but its easy, cheap, and environmentally friendly synthesis is still a grand challenge. Herein we directly synthesized porous NCN material via the facile pyrolysis of chitosan and urea without the requirement of any catalyst or post-treatment. As-prepared material exhibits a very large BET surface area of ∼1510 m² g^–1 and a high ratio of graphitic/pyridinic nitrogen structure (2.69 at. % graphitic N and 1.20 at. % pyridinic N). Moreover, compared to a commercial Pt/C catalyst, NCN displays excellent electrocatalytic activity, better long-term stability, and methanol tolerance ability toward the oxygen reduction reaction, indicating a promising metal-free alternative to Pt-based cathode catalysts in alkaline fuel cells. This scalable fabrication method supplies a low-cost, high-efficiency metal-free oxygen reduction electrocatalyst and also suggests an economic and sustainable route from biomass-based molecules to value-added nanocarbon materials

Active Mechanism of the Interphase Film-Forming Process for an Electrolyte Based on a Sulfolane Solvent and a Chelato-Borate Complex

Electrolytes based on sulfolane (SL) solvents and lithium bis­(oxalato)­borate (LiBOB) chelato-borate complexes have been reported many times for use in advanced lithium-ion batteries due to their many advantages. This study aims to clarify the active mechanism of the interphase film-forming process to optimize the properties of these batteries by experimental analysis and theoretical calculations. The results indicate that the self-repairing film-forming process during the first cycle is divided into three stages: the initial film formation with an electric field force of ∼1.80 V, the further growth of the preformation solid electrolyte interphase (SEI) film at ∼1.73 V, and the final formation of a complete SEI film at a potential below 0.7 V. Additionally, we can deduce that the decomposition of LiBOB and SL occurs throughout nearly the entire process of the formation of the SEI film. The decomposition product of BOB^– anions tends to form films with an irregular structure, whereas the decomposition product of SL is in favor of the formation of a uniform SEI film

sj-pdf-1-imr-10.1177_03000605221148905 - Supplemental material for Prevalence and management of hypertension in Central China: a cross-sectional survey

Supplemental material, sj-pdf-1-imr-10.1177_03000605221148905 for Prevalence and management of hypertension in Central China: a cross-sectional survey by Wenlu Xing, Shan Wang, Xinyun Liu, Jicheng Jiang, Qiuping Zhao, Yuming Wang, You Zhang and Chuanyu Gao in Journal of International Medical Research</p