2D/2D Ti_(3)C_(2) MXene/HTiNbO5 nanosheets Schottky heterojunction for boosting photothermal-assisted solar-driven photodegradation of tetracycline hydrochloride

Developing high-efficiency photocatalysts for tetracycline hydrochloride(TCH)degradation is of great sig-nificance to ecosystems and human beings.In this work,a two-step process of exfoliation and re-stacking was performed to prepare re-stacked HTiNbO_(5) nanosheets(R-HTNS)and then coupled with Ti_(3)C_(2) MXene to construct Ti_(3)C_(2) MXene/R-HTNS(MX/RTS)with a 2D/2D Schottky heterojunction.These 2D/2D het-erostructures between Ti_(3)C_(2) MXene and R-HTNS can produce an internal electric field and provide max-imum interface area for efficient charge transfer across the intimate interface.The photocatalytic perfor-mance of samples was evaluated by TCH degradation under simulated sunlight.The MX/RTS composites,with an optimal sample of 3-MX/RTS,show enhanced photocatalytic activity for TCH degradation com-pared with R-HTNS.The characterization results reveal that the introduction of Ti_(3)C_(2) MXene can signif-icantly increase specific surface area for providing more reactive sites and broaden the light absorption region.Besides,the incident light energy is absorbed by the Ti_(3)C_(2) MXene component in MX/RTS compos-ites to generate photothermal energy(heat),which facilitates the charge carrier separation and surface reaction kinetics.Thus,the enhanced TCH photodegradation activity for MX/RTS composites is due to the introduction of Ti_(3)C_(2) MXene,which possesses the synergistic effect of the increased specific surface area,improved light-harvesting capacity,2D/2D Schottky heterojunction,and photothermal energy effect.Additionally,the TCH photodegradation behavior is deliberated with a detailed discussion on various co-existing ions.During TCH photodegradation,the active radical species are determined for 3-MX/RTS.Ac-cording to the characterization results,the possible TCH photodegradation pathway and mechanism over 3-MX/RTS are explored.This work may offer a novel insight for constructing MXene-based heterostruc-tured photocatalysts with high efficiency.

Construction of novel g-C_(3)N_(4)/β-FeOOH Z-Scheme heterostructure photocatalyst modified with carbon quantum dots for efficient degradation of RhB

The degradation of organic pollutants using semiconductor photocatalysts is a new ecological approach,but the currently available photocatalysts are not very efficient.Herein,in order to obtain efficient visible-light photocatalysts,g-C_(3)N_(4)/β-FeOOH-modified carbon quantum dots(CDs)composite photocat-alysts with Z-Scheme charge transfer mechanism were successfully synthesized.The phase composition and morphology of the composite were characterized by X-ray diffraction(XRD),scanning electron mi-croscopy(SEM),transmission electron microscopy(TEM),Fourier transform infrared spectrophotometry(FT-IR),and X-ray photoelectron spectroscopy(XPS)techniques.Due to the upconversion effect of the CDs,the optical response range of the composite was effectively widened,and the optical utilization rate was improved.The Z-Scheme heterostructure not only improves the light trapping ability,significantly inhibits charge-carrier complexation,and realizes the spatial separation of redox sites,but also ensures that the photocatalyst maintains a suitable valence-conductivity band position and maintains the strong redox reactivity.In addition,CDs have the unique characteristics of electronic storage and transfer,which effectively enhance the quantum separation efficiency of the composite.The photocatalytic efficiency was measured by degrading rhodamine B(RhB)under visible light.The degradation performance was the best when the weight ratio of CDs was 6%,and the RhB solution degradation rate reached 100%in 60 min.The unique structure and reliable mechanism provide a way for the development of advanced photocat-alyst.

Protective layer for stable lithium-metal anodes at 60 mA·h/cm^(2) and 60 mA/cm^(2) with ion channel and inductive effect

Contradiction between ultrafast nucleation and deposition rates of lithium(Li)crystals at high rate and heterogeneity of Li^(+)flux resulting from concentration polarization has compromised the performance of Li metal anodes especially at high areal capacity and current density.Here,multifunctional protective layer consisting of MoO_(3) nanobelt films(MoO_(3)-NF)is introduced on the surface of Li by a simple rolling method.The strong binding energy between Li and MoO_(3) guides the homogeneous nucleation and deposition of Li,while the nanobelt networks provide effective ion channels for uniform distribution of the Li+flux.Because of the novel multifunctional protective layer,the MoO_(3)-NF@Li anodes demonstrate a remarkable stability for 800 h with ultralow overpotential of 159 mV at extreme harsh conditions of 60 mA·h/cm^(2) and 60 mA/cm^(2).MoO_(3)-NF@Li||LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2) full-cells can run 100 cycles with a superior capacity retention of 84.2%under practical test conditions,demonstrating great potential for high output and energy-density metal batteries.

1D/2D CoTe_(2)@MoS_(2)composites constructed by CoTe_(2)nanorods and MoS_(2)nanosheets for efficient electromagnetic wave absorption

Rational design of the components and microstructure is regarded as an efficacious strategy for the high-performance electromagnetic wave absorbing(EMWA)materials.Herein,the CoTe_(2)@MoS_(2)nanocomposites with CoTe_(2)nanorods and MoS_(2)nanosheets were synthesized via a hydrothermal method.The microstructure and composition of the samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The CoTe_(2)@MoS_(2)composite was composed of stacked CoTe_(2)as the core and intertwined MoS_(2)nanosheets as the shell.The electromagnetic parameters of the CoTe_(2)@MoS_(2)composites were investigated by vector network analyzer(VNA).The EMWA property of the composite showed a trend of first increasing and then decreasing with the increasing content of MoS_(2).When the mass ratio of MoS_(2)and CoTe_(2)was 1:1,the CoTe_(2)@MoS_(2)composite exhibited the minimum reflection loss value of-68.10 dB at 4.71 GHz,and the effective absorption bandwidth value might reach 4.64 GHz(13.08-17.72 GHz)at a matching thickness of 1.60 mm with filler loading of 50 wt.%.The extraordinary EMWA property was attributed to the optimized impedance matching,multiple scattering and reflections,dipole polarization,conductive loss,and interfacial polarization.Therefore,the present approach to the design of microstructure and interface engineering offers a crucial way to construct high-performance EMW absorbers.

Carbon nanotubes decorated FeNi/nitrogen-doped carbon composites for lightweight and broadband electromagnetic wave absorption

Magnetic-dielectric component modulation and heterogeneous interface engineering were considered as an effective strategy for designing lightweight and broadband electromagnetic wave(EMW)absorbors.Herein,a series of carbon nanotubes(CNTs)decorated core-shell nitrogen-doped carbon(CNTs/FeNi/NC)composites were successfully fabricated via the carbonization of CNTs/NiFe_(2)O_(4)/PDA precursors obtained by hydrothermal and polymerization method.The EMW absorption(EMWA)properties of CNTs/FeNi/NC composites were explored by varying the CNTs content.When the CNTs content was 15%,the minimum reflection loss(RL_(min))value was-51.13 dB at 9.52 GHz and the corresponding effective absorption band-width(EAB)value was 2.96 GHz(8.96-11.12 GHz)at 2.5 mm.Particularly,the maximum EAB value can reach up to 4.64 GHz(12.80-17.44 GHz)at 1.7 mm.The excellent EMW attenuation capability resulted from the enhanced conductive loss,polarization loss,magnetic loss,and improved impedance matching.This work offers a novel reference for designing lightweight and broadband EMWA materials.