Graphitic carbon nitride/ferroferric oxide/reduced graphene oxide nanocomposite as highly active visible light photocatalyst

High stability and efficient charge separation are two critical factors to construct high-performance photocatalysts.Here,an efficient strategy was provided to fabricate the nanocomposite of graphitic carbon nitride/ferroferric oxide/reduced graphene oxide(g-C_(3)N_(4)/Fe_(3)O_(4)/RGO).The degradation of rhodamine B(RhB)by g-C_(3)N_(4)/Fe_(3)O_(4)/RGO nanocomposite followed the pseudofirst-order kinetics.The g-C_(3)N_(4)/Fe_(3)O_(4)/RGO nanocomposite exhibited excellent stability and magnetically separable performance.It was ascertained that the quantum efficiency and separation efficiency of photoexcited charge carriers of g-C_(3)N_(4)/Fe_(3)O_(4)/RGO nanocomposite were obviously improved.Particularly,the g-C_(3)N_(4)/Fe_(3)O_(4)/RGO nanocomposite with 3 wt.%RGO presented 100%degradation efficiency under visible light irradiation for 75 min.The remarkable photocatalytic degradation activity is attributed to the synergistic interactions among g-C_(3)N_(4),Fe_(3)O_(4),and RGO,along with the efficient interfacial charge separation.

MoS_(2) wrapped MOF-derived N-doped carbon nanocomposite with wideband electromagnetic wave absorption

Designing electromagnetic wave absorption(EMWA)materials with wide bandwidth,strong absorption,and light weight is still a great challenge for practical applications.Herein,the novel nitrogen doped carbon(NDC)/MoS_(2) composite with rationally designed composition and structure was developed.The NDC particles were introduced into MoS_(2) nanosheets through the calcination of ZIF-8 precursor and consequent hydrothermal process.A series of characterizations were carried out to investigate the physical properties of the as-prepared nanocomposites.The NDC particles exhibited the shape of rhombic dodecahedron with the size of about 500 nm,which were decorated on flower-shaped MoS_(2) with the size of about 3μm.With the increasing NDC content,the absorbing properties of NDC/MoS_(2) composites increased firstly and then decreased.The features of NDC/MoS_(2) composite including interconnected porous structure,nitrogen dopant,and appropriate electrical conductivity gave rise to the polarization,multiple reflection,multiple scattering,and impedance matching,resulting in the outstanding EMWA performance.With a filler loading ratio of 30 wt.%,the optimized EMWA property can be achieved when the mass ratio of NDC to MoS_(2) was adjusted to be 1:1.At a coating thickness of 3.0 mm,the effective EMWA bandwidth(<−10 dB)reached 6.08 GHz(8.56–14.64 GHz).These satisfactory achievements provide a way for the reasonable design of high-performance EMWA and new ideas for future research on wideband EMWA.

Hierarchically porous carbon derived from natural Porphyra for excellent electromagnetic wave absorption

A highly efficient absorber with features including lightweight, broad bandwidth, and tunable electromagnetic property still remains challenging for practical applications. Herein, the Porphyra-derived porous carbon(PPC) was fabricated via facile procedures of low-temperature pre-carbonization combined with KOH chemical activation. The composition, microstructure, and electromagnetic wave absorption properties of the samples were elucidated based on X-ray diffraction(XRD), Raman, X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), transmission electron microscopy(TEM),Brunauer-Emmer-Teller(BET), and vector network analyzer(VNA). The porosity of PPC can be readily regulated by adjusting activation temperature. The PPC obtained at 750 ℃ was composed of a threedimensional hierarchically porous carbon network. The C and N elements of natural Porphyra were introduced into the carbon skeleton during the carbonization process. The large specific surface, dopants, and three-dimensional hierarchically porous carbon network can effectively improve the impedance matching and dielectric dissipation, leading to an excellent electromagnetic wave absorption performance. Especially, the optimal reflection loss(RL) value reached –57.75 d B at 9.68 GHz with a broad bandwidth(RL< –10 d B) value of 7.60 GHz at 3.5 mm. Overall, the results indicate that the PPC can provide a new way to achieve lightweight, effective, and sustainable absorbers.