Le-Xi Zhang

Nitrogen-Deficient Graphitic Carbon Nitride with Enhanced Performance for Lithium Ion Battery Anodes

Graphitic carbon nitride (g-C3N4) behaving as a layered feature with graphite was indexed as a high-content nitrogen-doping carbon material, attracting increasing attention for application in energy storage devices. However, poor conductivity and resulting serious irreversible capacity loss were pronounced for g-C3N4 material due to its high nitrogen content. In this work, magnesiothermic denitriding technology is demonstrated to reduce the nitrogen content of g-C3N4 (especially graphitic nitrogen) for enhanced lithium storage properties as lithium ion battery anodes. The obtained nitrogen-deficient g-C3N4 (ND-g-C3N4) exhibits a thinner and more porous structure composed of an abundance of relatively low nitrogen doping wrinkled graphene nanosheets. A highly reversible lithium storage capacity of 2753 mAh/g was obtained after the 300th cycle with an enhanced cycling stability and rate capability. The presented nitrogen-deficient g-C3N4 with outstanding electrochemical performances may unambiguously promote the application of g-C3N4 materials in energy-storage devices.

Ppt-level benzene detection and gas sensing mechanism using (C4H9NH3)2PbI2Br2 organic-inorganic layered perovskite

Benzene and formaldehyde are representatives of volatile organic compounds (VOCs), which are harmful to human beings due to their highly toxic and carcinogenic nature. So exploring efficient gas sensing materials to detect ultra-low concentration benzene is of utmost significance. In this paper, an organic–inorganic layered perovskite (C4H9NH3)2PbI2Br2 was synthesized through a facile solution method. And it was employed as a resistive gas sensing candidate to benzene, exhibiting ultrahigh response, fast response–recovery, good selectivity and repeatability for parts per trillion (ppt) level benzene detection at the optimum operation temperature (OOT) of 160 °C, with a response of 90.7 for 1 ppt benzene. In situ infrared analysis confirmed that the gas sensing mechanism is originated from the physical adsorption–desorption of benzene molecules onto the (C4H9NH3)2PbI2Br2 surface, the charge transfer model of which is different from that of conventional metal oxides. A promising application using such organic–inorganic hybrid perovskites for monitoring ultra-low concentration benzene might be interesting to researchers in the gas sensor field.