Non-graphitized carbon (NGC) has been extensively utilized as carbonaceous anode in sodium-ion batteries (SIBs). However, more optimization to achieve competitive capacity and stability is still challenging for SIBs. In the study, the dopant strategy is utilized to construct nitrogen/sulfur-doped non-graphitized carbon (N-NGC or S-NGC) shell decorated on three-dimensional graphene foam (GF) as a self-support electrode. The highly disordered microstructures of heteroatom doped carbons are produced by applying a low-temperature pyrolysis treatment to precursors containing nitrogen and sulfur. The DFT calculations of Na-ion adsorption energies at diverse heteroatom sites show marginal-S, pyrrolic N and pyridinic N with more intensive Na-ion adsorption ability than middle-S, C O and pristine carbon. The N-NGC with dominant small graphitic regions delivers adsorption ability to Na-ion, while the S-NGC with significant single carbon lattice stripes demonstrates redox reaction with Na-ion. Evidently, in comparison with only adsorption-driven slope regions at high potential for N-NGC, the redox reaction-generated potential-plateau enables non-graphitized S-NGC superior discharge/charge capacity and cycle-stability in the slope region. This work could provide deep insight into the rational design of non-graphitized carbon with rich microstructure and composition.
For the first time, a novel lead ion electrochemical sensor based on three-dimensional grapheme foam/sodium dodecyl benzene sulfonate hemimicelle (3D GF/SDBS HM) nanocomposite has been developed. This nanocomposite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared (FTIR) spectroscopy and contact angle measurements, which demonstrated that SDBS hemimicelles were attached on the surface of the 3D graphene foam. Electrochemical properties of the nanocomposite modified electrode were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. This electrochemical sensing interface exhibited excellent stripping performance for the analysis of Pb 2+ with the detection limit of 0.0145 nM, combining the advantageous of 3D graphene foam (well-defined macroporous structure, high electrical conductivity and specific area) together with the unique accumulating and depositing features of hemimicelle. The sensor was further applied to the determination of lead ion in real water samples with satisfactory results.
Zhao Wang,Hong Yan Yue,Ze Min Yu,Shuo Huang,Xin Gao,Bao Wang,Shan Shan Song,En Hao Guan,Wan Qiu Wang,Hong Jie Zhang
Spherical nickel nanoparticles were prepared by an N 2 H 4 -based solution reduction route. Then, graphene was deposited on the template of nickel nanoparticles by chemical vapor deposition (CVD) at a high temperature. After etching nickel, small-sized, porous and free-standing 3D graphene foam (3D GF) was obtained. It was transferred on the indium tin oxide (ITO) glass (3D GF/ITO) for electrochemical determination of levodopa in the presence/absence of uric acid . The results show that the pore size of the 3D GF is ~1 μm. The electrode shows a high sensitivity of 0.24 μA·μM −1 for the detection of levodopa. The electrode also shows a low measured limit of detection, superior selectivity, reproducibility and stability. Meanwhile, it shows a great potential in the clinical application.
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