In situ approach of cementite nanoparticles encapsulated with nitrogen-doped graphitic shells as anode nanomaterials for Li-ion and Na-ion batteries.

Novel Fe3C nanoparticles encapsulated with nitrogen-doped graphitic shells were synthesized by floating catalytic pyrolysis. Due to the short synthesis time and controllable pyrolytic temperature, the diameters of Fe3C core nanoparticles ranged from 5 to 15 nm (Fe3C@NGS900 prepared at 900 °C) and the average thickness of N-doped graphitic shells was ∼1.2 nm, leading to their high electrochemical performance: specific capacity of 1300 mA h g-1 at current density 0.2 A g-1, outstanding rate capability of 939 mA h g-1 at 3 A g-1, improved initial coulombic efficiency (Fe3C@NGS900: 72.1% vs. NGS900 (pure graphitic shells): 52%) for lithium ion batteries (LIBs), and impressive long-term cycle performance (1399 mA h g-1 maintained at 3 A g-1 after 500 cycles for LIBs; 214 mA h g-1 maintained at 1 A g-1 after 500 cycles for sodium ion batteries).

Sulfur-Doping Templated Synthesis of Nanoporous Graphitic Nanocages and Its Supported Catalysts for Efficient Methanol Oxidation.

We demonstrate a new sulfur (S)-doping templated approach to fabricate highly nanoporous graphitic nanocages (GNCs) by air-oxidizing the templates in the graphitic shells to create nanopores. Sulfur can be introduced, when Fe@C core-shell nanoparticles are prepared and then S-doped GNCs can be obtained by removing their ferrous cores. Due to removing S-template, both the specific surface area (from 540 to 850 m2 g(-1)) and the mesopore volume (from 0.44 to 0.9 cm3 g(-1)) of the graphitic nanocages have sharply risen. Its high specific surface area improves catalyst loading to provide more reaction electro-active sites while its high mesopore volume pro- motes molecule diffusion across the nanocages, making it an excellent material to support Pt/Ru catalysts for direct methanol fuel cells.

Thin-walled graphitic nanocages as a unique platform for amperometric glucose biosensor.

A thin-walled graphitic nanocages material with well-developed graphitic structure, large specific surface area and pronounced mesoporosity was synthesized and used to construct a sensing interface for an amperometric glucose biosensor, showing a high and reproducible sensitivity of 13.3 µA mM(-1) cm(-2), linear dynamic range of 0.02-6.2 mM, and fast response time of 5 s. It was successfully used to accurately detect glucose in human serum with effective discrimination to common interference species such as dopamine, ascorbic acid, acetaminophen, and uric acid.