Dear Editor,This letter presents some control strategies for quadrotor unmanned aerial vehicle(UAV)leader-follower formation model,where the stochastic impulsive deception attacks are fully considered.Based on Lyapuno...Dear Editor,This letter presents some control strategies for quadrotor unmanned aerial vehicle(UAV)leader-follower formation model,where the stochastic impulsive deception attacks are fully considered.Based on Lyapunov method,the outer loop and the inner loop controllers of quadrotor UAV are designed,respectively.Moreover,a relationship between continuous control laws,stochastic impulsive sequences,and impulsive intensity is established in this letter.展开更多
The coupled nonlocal nonlinear Schrödinger equations with variable coefficients are researched using the nonstandard Hirota bilinear method.The two-soliton and double-hump one-soliton solutions for the equations ...The coupled nonlocal nonlinear Schrödinger equations with variable coefficients are researched using the nonstandard Hirota bilinear method.The two-soliton and double-hump one-soliton solutions for the equations are first obtained.By assigning different functions to the variable coefficients,we obtain V-shaped,Y-shaped,wave-type,exponential solitons,and so on.Next,we reveal the influence of the real and imaginary parts of the wave numbers on the double-hump structure based on the soliton solutions.Finally,by setting different wave numbers,we can change the distance and transmission direction of the solitons to analyze their dynamic behavior during collisions.This study establishes a theoretical framework for controlling the dynamics of optical fiber in nonlocal nonlinear systems.展开更多
In this work,Mn-doped MoS_(2)hierarchical nanotubes have been prepared by a solvothermal method.The diameter of Mn-MoS_(2)nanotubes is about 100–_(2)00 nm and the wall thickness is about 10–_(2)0 nm.Hierarchical ult...In this work,Mn-doped MoS_(2)hierarchical nanotubes have been prepared by a solvothermal method.The diameter of Mn-MoS_(2)nanotubes is about 100–_(2)00 nm and the wall thickness is about 10–_(2)0 nm.Hierarchical ultrathin sheets are formed on the surface of MoS_(2)nanotubes.展开更多
In the present investigation,we examined the water and oxygen reduction ability of ZnCr-layered double hydroxide decorated with Au nanoparticles and reduced graphene oxide,prepared via in situ crystallization and phot...In the present investigation,we examined the water and oxygen reduction ability of ZnCr-layered double hydroxide decorated with Au nanoparticles and reduced graphene oxide,prepared via in situ crystallization and photoreduction method.The fabricated Au@LDH/RGO composite was well characterized by different analytical instruments like PXRD,FTIR,Raman,XPS,EDX,FESEM,and TEM,suggesting strong interaction between the components of the ternary hybrid.Further,the Au@LDH/RGO catalyst shows the best hydrogen evolution reaction(HER),i.e.,918.76μmol/2 h(no.evolved H_(2)gas is 4.9903×10^(15)cm^(−2)s^(−1))with an ACE of 10.5%and excellent reusability up to 8 h with little change in activity.Additionally,the ternary nanohybrid depicts robust photocatalytic O_(2)reduction reaction performance,i.e.,24.3μmol/2 h of H_(2)O_(2)(SCC=0.23%),which goes via a superoxide radical mechanism as confirmed through tracing experiments.The observed high photocatalytic activity is attributed to the synergetic effect of both plasmonic Au nanoparticles and conjugatedΠ-skeleton of RGO,which resulted in high charge carrier density and reduction of the recombination process.This observation is well justified by Mott-Schottky,EIS,PL,and photocurrent measurements.Further,the HER performance was also tested under different hole scavengers to figure out their effect.The SPR effect of Au and conjugated cyclic carbon network of RGO plays a pivotal part in improving the H_(2)and H_(2)O_(2)generation ability of LDH under visible light illumination.展开更多
Developing highly efficient,Earth-abundant,and long-term stable electrocatalysts for the oxygen evolution reaction (OER) is of great importance for realizing industrial hydrogen generation from water splitting.Herein,...Developing highly efficient,Earth-abundant,and long-term stable electrocatalysts for the oxygen evolution reaction (OER) is of great importance for realizing industrial hydrogen generation from water splitting.Herein,a series of novel Fe and Nb co-doped β-Ni(OH)_(2)nanosheet arrays were successfully grown in situ on Ni foam via a chlorine etching method.The representative NiFe_(3)Nb_(2)-OH displayed outstanding OER performance with an overpotential of 294 mV to deliver 100 mA cm^(-2) in an alkaline electrolyte,outperforming other Ni related electrocatalysts.NiFe_(3)Nb_(2)-OH exhibited a stability of 90 h without obvious potential change at 50 mA cm^(-2).Significantly,the doped Fe and Nb effectively enhanced the electrochemical active area and electronic transfer capability of β-Ni(OH)_(2).Density functional theory (DFT) calculations indicated that the Gibbs free energy of the OER intermediates on the Fe,Nb co-doped β-Ni(OH)_(2)electrode was optimized.The tuned electronic interactions between Fe,Nb and Ni apparently boosted the OER performance of NiFe_(3)Nb_(2)-OH.These results demonstrated that Fe and Nb co-doped β-Ni(OH)_(2)is a highly efficient OER electrocatalyst in alkaline media.展开更多
TiO_(2)(B)nanotubes(NTs)were used as carriers to support metal Cu/Ni nanoparticles for the catalytic hydrolysis of ammonia borane(NH_(3)BH_(3),AB)under visible light.The TiO_(2)NTs were first prepared by the hydrother...TiO_(2)(B)nanotubes(NTs)were used as carriers to support metal Cu/Ni nanoparticles for the catalytic hydrolysis of ammonia borane(NH_(3)BH_(3),AB)under visible light.The TiO_(2)NTs were first prepared by the hydrothermal method and subsequently loaded with Cu/Ni metal nanoparticles by the impregnation reduction method.The structure,morphology,and chemical composition of the as-obtained catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy coupled with energy dispersive X-ray spectroscopy(SEM-EDX),transmission electron microscopy(TEM),inductively coupled plasma emission spectroscopy(ICP),and ultraviolet-visible spectroscopy(UV-Vis).The characterization results revealed that the metal nanoparticles were uniformly loaded on the surface of the TiO_(2)NTs,while the band gap of the catalyst was reduced significantly from 3.22 to 2.68 eV.The catalysts showed an excellent photocatalytic performance towards the hydrolysis of AB for H_(2)production.Thus,the H_(2)production rate of Cu_(0.64)Ni_(0.36)-TiO_(2)NTs reached 5763.86 mL g^(-1)min^(-1),with a total turnover frequency(TOF)of 15.90 mol H_(2)(mol cat)^(-1)min^(-1)for a loading volume of metal particles of 5.25 wt%.The results presented herein demonstrate that TiO_(2)(B)can be a potential photocatalyst for effective H_(2)production,and also provide a cheap and effective approach to improve the light-to-H_(2)energy conversion.展开更多
Electrocatalytic CO_(2) reduction reactions(CO_(2)RRs),an efficient method of converting carbon dioxide into valuable fuels and chemicals,are attractive as well as challenging.In this work,Cu_(2)O nanostructures with ...Electrocatalytic CO_(2) reduction reactions(CO_(2)RRs),an efficient method of converting carbon dioxide into valuable fuels and chemicals,are attractive as well as challenging.In this work,Cu_(2)O nanostructures with active facets(face-raised cubic structures(F-Cu_(2)O)with the(100)facet,octahedral structures(O-Cu_(2)O)with the(111)facet and edge-and corner-truncated octahedral structures(T-Cu_(2)O)with both the(100)and(111)facets)were synthesized by a wet chemical reduction method.The surface of Cu_(2)O nanostructures was reconstructed in situ to form Cu_(2)O/Cu with a highly active interface during the conversion of CO_(2) into C_(2)H_(4),which is named F-Cu_(2)O/Cu,O-Cu_(2)O/Cu and T-Cu_(2)O/Cu.The C_(2)H_(4) selectivity on Cu_(2)O/Cu catalysts follows the order of O-Cu_(2)O/Cu<F-Cu_(2)O/Cu<T-Cu_(2)O/Cu,and the faradaic efficiencies of C_(2)H_(4) are 11.2%,24.9%,and 58.0% at -1.1 V versus the reversible hydrogen electrode,respectively.The experimental results combined with operando surface-enhanced Raman spectroscopy reveal that the Cu_(2)O/Cu interface enhances *CO adsorption and decreases the activation energy of C-C coupling,which is also supported by density functional theory(DFT)calculations.This study will pave a feasible pathway for electrochemical energy storage and convention by crystal facet engineering and interface engineering.展开更多
A new mixed alkali hydro-isocyanurate,RbNa(HC_(3)N_(3)O_(3))·2H_(2)O,with the noncentrosymmetric space group Pna21(No.33),has been successfully grown by a hydrothermal method.The structure can be described as 2D ...A new mixed alkali hydro-isocyanurate,RbNa(HC_(3)N_(3)O_(3))·2H_(2)O,with the noncentrosymmetric space group Pna21(No.33),has been successfully grown by a hydrothermal method.The structure can be described as 2D wavy[Na(HC_(3)N_(3)O_(3))O_(4)]∞layers separated by Rb atoms.The UV-vis diffuse reflection measurement revealed that RbNa(HC_(3)N_(3)O_(3))·2H_(2)O has a large band gap of 5.10 eV,corresponding to the UV cutoff edge of 241 nm.The polarizing microscope measurement of a micron-sized single crystal shows that RbNa(HC_(3)N_(3)O_(3))·2H_(2)O has a large birefringence of 0.194.The powder SHG measurement indicated that RbNa(HC_(3)N_(3)O_(3))·2H_(2)O exhibits a strong SHG effect that is 5.3 times that of KH_(2)PO_(4)(KDP)and can realize phase-matching in the visible and UV region.Moreover,the differences in the SHG responses between RbNa(HC_(3)N_(3)O_(3))·2H_(2)O and two isostructural compounds have been investigated,which depend heavily on the structural modulation of the(HC_(3)N_(3)O_(3))2-group by cations.Meanwhile,the electronic structures and optical properties were well analyzed using DFT methods.展开更多
Herein,we report the synthesis of hybrid nanostructures obtained by densely growing MoS_(2)nanosheet layers on hydrophobic hollow carbon spheres(abbreviated as MoS_(2)-HCS)through a solvothermal method.The morphologie...Herein,we report the synthesis of hybrid nanostructures obtained by densely growing MoS_(2)nanosheet layers on hydrophobic hollow carbon spheres(abbreviated as MoS_(2)-HCS)through a solvothermal method.The morphologies and compositions of the MoS_(2)-HCS hybrid are well investigated.The electrochemical performance of the MoS_(2)-HCS sphere is investigated in both supercapacitors and the hydrogen evolution reaction.展开更多
In the quest for amplifying the inherent capabilities of noble metals,crafting precise metal–support interfacial bonds stands as a challenging yet fruitful endeavor.Here,we introduce an approach to synthesize excepti...In the quest for amplifying the inherent capabilities of noble metals,crafting precise metal–support interfacial bonds stands as a challenging yet fruitful endeavor.Here,we introduce an approach to synthesize exceptionally small metal nanoparticles(NPs),which are securely anchored onto cobalt-based metal–organic framework(Co-MOF)nanosheets through a wet chemical method.The creation of metal–oxygen linkages between these Ir NPs and Co-MOF not only guarantees structural robustness but also ensures a generous exposure of active sites.Importantly,the distinct interface fine-tunes the electronic configuration of the composites by facilitating charge transfer along the Ir–O–Co pathway,consequently boosting the reaction dynamics.As a result,the hydrogen evolution reaction(HER)performance of our pioneering product,Ir@Co-MOF,in alkaline media,rivals that of the benchmark Pt/C catalyst and surpasses other recent noble metal catalysts.Theoretical analysis reveals that the exceptional HER efficiency of Ir@Co-MOF originates from the optimal adsorption energies for water and hydrogen,a consequence of electron re-allocation owing to its unique interfacial bond.展开更多
Developing low-cost and efficient catalysts for hydrogen evolution is of great significance to solve the human energy crisis.In this work,ruthenium-nickel alloy is synthesized by a solvothermal method.The ruthenium-ni...Developing low-cost and efficient catalysts for hydrogen evolution is of great significance to solve the human energy crisis.In this work,ruthenium-nickel alloy is synthesized by a solvothermal method.The ruthenium-nickel alloy shows distinguished catalytic performance and durability for the hydrogen evolution reaction in alkaline solution(1 M KOH).Only 21,76,222 and 323 mV overpotentials are required to reach current densities of 10,100,1000 and 2000 mA cm^(-2).After 150 hours of a durability test at a current density of-400 mA cm^(-2),the alloy also shows outstanding durability.Density functional theory(DFT)further shows that ruthenium-nickel alloy composites can optimize the reaction barrier of alkaline hydrogen evolution.This study provides a valuable method for developing high-performance and lowprice alloy catalysts for hydrogen evolution.展开更多
A highly active heterogeneous catalyst,Pd nanoparticles@g-C_(3)N_(4)/SiO_(2) with tunable band structure,was successfully fabricated by a sol–gel method.The nanocomposite catalyst exhibits an extraordinary hydrogen p...A highly active heterogeneous catalyst,Pd nanoparticles@g-C_(3)N_(4)/SiO_(2) with tunable band structure,was successfully fabricated by a sol–gel method.The nanocomposite catalyst exhibits an extraordinary hydrogen production rate from formic acid which leads to a high turnover frequency(TOF)of around 306 mol H_(2) per mole Pd per h after 10 min.The characterization analysis shows that the bandgap of the g-C_(3)N_(4)/SiO_(2) support widens with decreasing synthesis temperature,which in turn allows tuning of the band structure by simply controlling the synthesis temperature.After Pd nanoparticles were embedded,the nanocomposite Pd@g-C_(3)N_(4)/SiO_(2) showed excellent catalytic performance in the dehydrogenation of formic acid at 303.15 K,and the lower the synthesis temperature of the catalyst,the higher its performance.展开更多
Carbon anode materials for Li-ion batteries have been operated close to their theoretical rate and cycle limits.Therefore,titanium-based materials have attracted great attention due to their high stability.Here,Na_(2)...Carbon anode materials for Li-ion batteries have been operated close to their theoretical rate and cycle limits.Therefore,titanium-based materials have attracted great attention due to their high stability.Here,Na_(2)Li_(2)Ti_(6)O_(14)nanofibers as anode materials were prepared through a controlled electrospinning method.The Na_(2)Li_(2)Ti_(6)O_(14)nanofibers presented superior electrochemical performance with high rate capability and long cycle life and can be regarded as a competitive anode candidate for advanced Li-ion batteries.One-dimensional(1D)Na_(2)Li_(2)Ti_(6)O_(14)nanofibers are able to deliver a capacity of 128.5 mA h g^(-1)at 0.5C,and demonstrate superior high-rate charge-discharge capability and cycling stability(the reversible charge capacity is 77.8 mA h g^(-1)with a capacity retention of 99.45%at the rate of 10C after 800 cycles).The 1D structure is considered to contribute remarkably to increased rate capability and stability.This simple and scalable method indicates that the Na_(2)Li_(2)Ti_(6)O_(14)nanofibers have a practical application potential for high performance lithium-ion batteries.展开更多
In this paper,we report the highly selective and sensitive electrochemical determination of dopamine(DA)based on an iron oxide nanoparticle-(Fe_(2)O_(3)NP)capped graphene sheet(GRS)modified glassy carbon electrode(GCE...In this paper,we report the highly selective and sensitive electrochemical determination of dopamine(DA)based on an iron oxide nanoparticle-(Fe_(2)O_(3)NP)capped graphene sheet(GRS)modified glassy carbon electrode(GCE).The Fe_(2)O_(3)NPs were synthesized by a pyrophoric technique and their nanocomposite with GRS was prepared by a simple sonochemical method.The as-prepared Fe_(2)O_(3)NP/GRS nanocomposite was characterized using scanning electron microscopy,electron dispersive X-ray spectroscopy,Raman spectroscopy,X-ray diffraction,Fourier transform infrared spectroscopy and electrochemical impedance spectroscopy.As expected,the proposed sensor exhibits a wide linear range from 0.01 to 195.18,a low detection limit(LOD)of 0.004μM for the DPV technique and a broad linear range from 0.006 to 635μM,and a very low detection limit of 0.001μM for the amperometric technique.Moreover,it shows excellent selectivity of DA even in the presence of a 20-fold higher concentration of potential interferences.The practical applicability of the reported sensor was recorded in human serum and urine samples.Finally,all electrochemical studies confirmed the excellent electrocatalytic activity of the Fe_(2)O_(3)NP/GRS nanocomposite as a DA sensor.展开更多
A hybrid core-shell material based on carbon nanofibers(CNFs)and a 2D conductive metal-organic framework(Ni-CAT)has been synthesized as a flexible free-standing membrane by combining electrospinning technology with a ...A hybrid core-shell material based on carbon nanofibers(CNFs)and a 2D conductive metal-organic framework(Ni-CAT)has been synthesized as a flexible free-standing membrane by combining electrospinning technology with a hydrothermal method.The as-made CNF@Ni-CAT exhibits a high specific capacitance of 502.95 F g^(-1)at a current density of 0.5 A g^(-1)and an improved cycling stability of 73%capacitance retention over 5000 cycles as an electrode material for supercapacitors due to its excellent synergistic effect.展开更多
The development of multiple metal-organic framework(MOF)thin films with high lattice mismatch is still a challenging task.Herein we report a series of single and multiple(bi-varietal and tri-varietal)pillarlayered MOF...The development of multiple metal-organic framework(MOF)thin films with high lattice mismatch is still a challenging task.Herein we report a series of single and multiple(bi-varietal and tri-varietal)pillarlayered MOF thin films(surface-coordinated MOF thin films,SURMOFs)[Cu_(2)L_(2)dabco]_(n)(L=bdc,bpc and tpdc)with preferred[001]-orientation on the substrate surfaces using a liquid-phase epitaxial(LPE)layer by layer pump method.The single SURMOFs with the same c-lattice parameters but different a-and b-lattice parameters result in the successful growth of oriented multiple SURMOFs with high lattice mismatch(up to 77.8%).The vapor adsorption results show that the representative bi-varietal SURMOF with large lattice mismatch has different adsorption behavior from single SURMOFs,providing a new strategy to achieve tuning of the adsorption kinetics performance in sensing applications.展开更多
The geometrical structures of Wells-Dawson derivatives[X-C(CH_(2)O)_(3)P_(2)M’_(3)M_(15)O_(59)]^(6-)(X=NO_(2),NH_(2),and CH_(3),M’=V and Nb,M=W and Mo)have been calculated by the density functional theory(DFT)method...The geometrical structures of Wells-Dawson derivatives[X-C(CH_(2)O)_(3)P_(2)M’_(3)M_(15)O_(59)]^(6-)(X=NO_(2),NH_(2),and CH_(3),M’=V and Nb,M=W and Mo)have been calculated by the density functional theory(DFT)method.The results show that the distances of P…P and P…C are controlled by the{M’_(3)}triads,and{M’_(3)}triads also affect the sizes of W_(6) hexagonal belts.The second-order polarizabilities and origin of nonlinear optical(NLO)properties of those clusters have been investigated by a time-dependent density functional theory(TDDFT)method.The NLO property analysis reveals that[X-C(CH_(2)O)3P_(2)V_(3)Mo_(15)O_(59)]^(6-)(X=NH_(2))anions have the largest β_(vec) values,75.064×10^(-30) esu.Grafting electron donors to POM clusters is an efficient way to improve the NLO response.The major electron transition orbitals show that the charge transfer from the organic groups to the metal atoms is responsible for the NLO properties of these polyoxometalates.展开更多
MoSe_(2) has been recognized as a promising anode material for lithium/sodium ion batteries due to its unique structure and material properties.Here,hierarchical MoSe_(2)@C hollow nanospheres(MoSe_(2)@C HNSs)assembled...MoSe_(2) has been recognized as a promising anode material for lithium/sodium ion batteries due to its unique structure and material properties.Here,hierarchical MoSe_(2)@C hollow nanospheres(MoSe_(2)@C HNSs)assembled with ultrathin nanosheets are prepared via a facile solvothermal method.The MoSe_(2)@C HNS composite is fabricated by an anion-exchange reaction from Mo-glycerate solid spheres combining with the carbonization of glucose.When used as an anode material for LIBs,the MoSe_(2)@C HNS composite manifests a reversible capacity of 711 mA h g^(−1) after 300 cycles under a current density of 500 mA g^(−1).When evaluated as an anode material for SIBs,the MoSe_(2)@C HNS composite delivers a high capacity of 683 mA h g^(−1) at 100 mA g^(−1) and maintains a capacity of 458 mA h g^(−1) after 200 cycles at 200 mA g^(−1).The efficient lithium and sodium ion storage performance should be ascribed to the unique hierarchical hollow nanostructure and synchronously incorporated carbon material.展开更多
The Lindqvist anion[Mo_(6)O_(19)]^(2−)was in situ intercalated into layered double hydroxides(LDHs)via a onepot hydrothermal method.The heterogeneous catalyst was applied in ultra-deep desulfurization of fuels under m...The Lindqvist anion[Mo_(6)O_(19)]^(2−)was in situ intercalated into layered double hydroxides(LDHs)via a onepot hydrothermal method.The heterogeneous catalyst was applied in ultra-deep desulfurization of fuels under mild conditions,and exhibited high activity for dibenzothiophene(DBT),benzothiophene(BT)and 4,6-dimethyldibenzothiophene(4,6-DMDBT).The above sulfur-containing compounds could be completely transformed into their corresponding sulfones under the stoichiometric O/S molar ratio(O/S molar ratio=2).Furthermore,the catalyst could be easily recovered and reused at least 7 times without an obvious decrease in performance.The possible desulfurization mechanism was also studied in detail.展开更多
A novel electrochemical sensor based on a graphene oxide(GO)/three-dimensional(3D)hierarchical zinc oxide(ZnO)nanocomposite was developed for the efficient determination of the antibiotic drug chloramphenicol(CAP).The...A novel electrochemical sensor based on a graphene oxide(GO)/three-dimensional(3D)hierarchical zinc oxide(ZnO)nanocomposite was developed for the efficient determination of the antibiotic drug chloramphenicol(CAP).The hierarchical ZnO structure consisting of nanosheets was synthesized by a green aqueous solution procedure and then composited with GO through a simple sonochemical method.The synthesized ZnO and GO/ZnO nanomaterials were characterized by scanning electron microscopy(SEM),elemental mapping,X-ray diffraction(XRD),UV-Visible spectroscopy,Fourier transform infrared spectroscopy(FT-IR),and Raman spectroscopy.The electrochemical performance of the prepared GO/ZnO/glassy carbon electrode(GCE)was evaluated using cyclic voltammetry(CV)and differential pulse voltammetry(DPV)techniques.The GO/ZnO/GCE shows a low CAP detection limit of 0.01μM,a high sensitivity of 7.27μAμM^(−1) cm^(−2),and a linear response in the range of 0.2 to 7.2μM.Moreover,it exhibits excellent stability,reproducibility and repeatability.Practicality of the sensor has further been demonstrated with honey,milk and eye drop samples.展开更多
基金supported by the National Natural Science Foundation of China(62173215)the Project for the Integrated Development of the City and Universities in Jinan(JNSX2024016)。
文摘Dear Editor,This letter presents some control strategies for quadrotor unmanned aerial vehicle(UAV)leader-follower formation model,where the stochastic impulsive deception attacks are fully considered.Based on Lyapunov method,the outer loop and the inner loop controllers of quadrotor UAV are designed,respectively.Moreover,a relationship between continuous control laws,stochastic impulsive sequences,and impulsive intensity is established in this letter.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1604200)the National Natural Science Foundation of China(Grant No.12261131495)Institute of Systems Science,Beijing Wuzi University(Grant No.BWUISS21).
文摘The coupled nonlocal nonlinear Schrödinger equations with variable coefficients are researched using the nonstandard Hirota bilinear method.The two-soliton and double-hump one-soliton solutions for the equations are first obtained.By assigning different functions to the variable coefficients,we obtain V-shaped,Y-shaped,wave-type,exponential solitons,and so on.Next,we reveal the influence of the real and imaginary parts of the wave numbers on the double-hump structure based on the soliton solutions.Finally,by setting different wave numbers,we can change the distance and transmission direction of the solitons to analyze their dynamic behavior during collisions.This study establishes a theoretical framework for controlling the dynamics of optical fiber in nonlocal nonlinear systems.
基金supported by the NationalNatural Science Foundation of China(No.11774188)the Incubation Program of Universities'Preponderant Discipline of Shandong Province(No.03010304)+1 种基金Mountain Tai Young Scholarship(No.23170504)the Natural Science Foundation of Shandong Province(No.ZR2018QB003,JQ201802).
文摘In this work,Mn-doped MoS_(2)hierarchical nanotubes have been prepared by a solvothermal method.The diameter of Mn-MoS_(2)nanotubes is about 100–_(2)00 nm and the wall thickness is about 10–_(2)0 nm.Hierarchical ultrathin sheets are formed on the surface of MoS_(2)nanotubes.
文摘In the present investigation,we examined the water and oxygen reduction ability of ZnCr-layered double hydroxide decorated with Au nanoparticles and reduced graphene oxide,prepared via in situ crystallization and photoreduction method.The fabricated Au@LDH/RGO composite was well characterized by different analytical instruments like PXRD,FTIR,Raman,XPS,EDX,FESEM,and TEM,suggesting strong interaction between the components of the ternary hybrid.Further,the Au@LDH/RGO catalyst shows the best hydrogen evolution reaction(HER),i.e.,918.76μmol/2 h(no.evolved H_(2)gas is 4.9903×10^(15)cm^(−2)s^(−1))with an ACE of 10.5%and excellent reusability up to 8 h with little change in activity.Additionally,the ternary nanohybrid depicts robust photocatalytic O_(2)reduction reaction performance,i.e.,24.3μmol/2 h of H_(2)O_(2)(SCC=0.23%),which goes via a superoxide radical mechanism as confirmed through tracing experiments.The observed high photocatalytic activity is attributed to the synergetic effect of both plasmonic Au nanoparticles and conjugatedΠ-skeleton of RGO,which resulted in high charge carrier density and reduction of the recombination process.This observation is well justified by Mott-Schottky,EIS,PL,and photocurrent measurements.Further,the HER performance was also tested under different hole scavengers to figure out their effect.The SPR effect of Au and conjugated cyclic carbon network of RGO plays a pivotal part in improving the H_(2)and H_(2)O_(2)generation ability of LDH under visible light illumination.
基金supported by the Natural Science Foundation of China(No.21776248 and 21676246)the Zhejiang Provincial Natural Science Foundation of China(No.LR17B060003)supported by the Fundamental Research Funds for the Central Universities.
文摘Developing highly efficient,Earth-abundant,and long-term stable electrocatalysts for the oxygen evolution reaction (OER) is of great importance for realizing industrial hydrogen generation from water splitting.Herein,a series of novel Fe and Nb co-doped β-Ni(OH)_(2)nanosheet arrays were successfully grown in situ on Ni foam via a chlorine etching method.The representative NiFe_(3)Nb_(2)-OH displayed outstanding OER performance with an overpotential of 294 mV to deliver 100 mA cm^(-2) in an alkaline electrolyte,outperforming other Ni related electrocatalysts.NiFe_(3)Nb_(2)-OH exhibited a stability of 90 h without obvious potential change at 50 mA cm^(-2).Significantly,the doped Fe and Nb effectively enhanced the electrochemical active area and electronic transfer capability of β-Ni(OH)_(2).Density functional theory (DFT) calculations indicated that the Gibbs free energy of the OER intermediates on the Fe,Nb co-doped β-Ni(OH)_(2)electrode was optimized.The tuned electronic interactions between Fe,Nb and Ni apparently boosted the OER performance of NiFe_(3)Nb_(2)-OH.These results demonstrated that Fe and Nb co-doped β-Ni(OH)_(2)is a highly efficient OER electrocatalyst in alkaline media.
基金supported by the key Basic Research Programme of Hebei Province of China(17964401D)the National Natural Science Foundation of China(No.21603052,51771068 and 51771067)the Natural Science Foundation of Hebei Province(No.B201820167).
文摘TiO_(2)(B)nanotubes(NTs)were used as carriers to support metal Cu/Ni nanoparticles for the catalytic hydrolysis of ammonia borane(NH_(3)BH_(3),AB)under visible light.The TiO_(2)NTs were first prepared by the hydrothermal method and subsequently loaded with Cu/Ni metal nanoparticles by the impregnation reduction method.The structure,morphology,and chemical composition of the as-obtained catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy coupled with energy dispersive X-ray spectroscopy(SEM-EDX),transmission electron microscopy(TEM),inductively coupled plasma emission spectroscopy(ICP),and ultraviolet-visible spectroscopy(UV-Vis).The characterization results revealed that the metal nanoparticles were uniformly loaded on the surface of the TiO_(2)NTs,while the band gap of the catalyst was reduced significantly from 3.22 to 2.68 eV.The catalysts showed an excellent photocatalytic performance towards the hydrolysis of AB for H_(2)production.Thus,the H_(2)production rate of Cu_(0.64)Ni_(0.36)-TiO_(2)NTs reached 5763.86 mL g^(-1)min^(-1),with a total turnover frequency(TOF)of 15.90 mol H_(2)(mol cat)^(-1)min^(-1)for a loading volume of metal particles of 5.25 wt%.The results presented herein demonstrate that TiO_(2)(B)can be a potential photocatalyst for effective H_(2)production,and also provide a cheap and effective approach to improve the light-to-H_(2)energy conversion.
基金supported by the 111 Project(Grant No.D17007)Henan Center for Outstanding Overseas Scientists(Grant No.GZS2022017)the National Science Foundation of China(Grant No.21908045,52072114,51922008 and 51872075).
文摘Electrocatalytic CO_(2) reduction reactions(CO_(2)RRs),an efficient method of converting carbon dioxide into valuable fuels and chemicals,are attractive as well as challenging.In this work,Cu_(2)O nanostructures with active facets(face-raised cubic structures(F-Cu_(2)O)with the(100)facet,octahedral structures(O-Cu_(2)O)with the(111)facet and edge-and corner-truncated octahedral structures(T-Cu_(2)O)with both the(100)and(111)facets)were synthesized by a wet chemical reduction method.The surface of Cu_(2)O nanostructures was reconstructed in situ to form Cu_(2)O/Cu with a highly active interface during the conversion of CO_(2) into C_(2)H_(4),which is named F-Cu_(2)O/Cu,O-Cu_(2)O/Cu and T-Cu_(2)O/Cu.The C_(2)H_(4) selectivity on Cu_(2)O/Cu catalysts follows the order of O-Cu_(2)O/Cu<F-Cu_(2)O/Cu<T-Cu_(2)O/Cu,and the faradaic efficiencies of C_(2)H_(4) are 11.2%,24.9%,and 58.0% at -1.1 V versus the reversible hydrogen electrode,respectively.The experimental results combined with operando surface-enhanced Raman spectroscopy reveal that the Cu_(2)O/Cu interface enhances *CO adsorption and decreases the activation energy of C-C coupling,which is also supported by density functional theory(DFT)calculations.This study will pave a feasible pathway for electrochemical energy storage and convention by crystal facet engineering and interface engineering.
基金supported by the National Natural Science Foundation of China(Grant No 21975255,51890862,U1605245,and 51425205)the National Key Research and Development Plan of Ministry of Science and Technology(Grant No 2016YFB0402104)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No XDB20000000)the NSF of Fujian Province(2019J01020758)the Youth Innovation Promotion Association CAS(303).
文摘A new mixed alkali hydro-isocyanurate,RbNa(HC_(3)N_(3)O_(3))·2H_(2)O,with the noncentrosymmetric space group Pna21(No.33),has been successfully grown by a hydrothermal method.The structure can be described as 2D wavy[Na(HC_(3)N_(3)O_(3))O_(4)]∞layers separated by Rb atoms.The UV-vis diffuse reflection measurement revealed that RbNa(HC_(3)N_(3)O_(3))·2H_(2)O has a large band gap of 5.10 eV,corresponding to the UV cutoff edge of 241 nm.The polarizing microscope measurement of a micron-sized single crystal shows that RbNa(HC_(3)N_(3)O_(3))·2H_(2)O has a large birefringence of 0.194.The powder SHG measurement indicated that RbNa(HC_(3)N_(3)O_(3))·2H_(2)O exhibits a strong SHG effect that is 5.3 times that of KH_(2)PO_(4)(KDP)and can realize phase-matching in the visible and UV region.Moreover,the differences in the SHG responses between RbNa(HC_(3)N_(3)O_(3))·2H_(2)O and two isostructural compounds have been investigated,which depend heavily on the structural modulation of the(HC_(3)N_(3)O_(3))2-group by cations.Meanwhile,the electronic structures and optical properties were well analyzed using DFT methods.
基金financially supported by the National Natural Science Foundation of China(51579057 and 51779065)the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(2016DX07)J.Liu acknowledges the support of the Doctoral Fund of the QUST,the Thousand Youth Talents Program of China,and the Natural Science Foundation of Shandong Province(No.ZR2018MB018).
文摘Herein,we report the synthesis of hybrid nanostructures obtained by densely growing MoS_(2)nanosheet layers on hydrophobic hollow carbon spheres(abbreviated as MoS_(2)-HCS)through a solvothermal method.The morphologies and compositions of the MoS_(2)-HCS hybrid are well investigated.The electrochemical performance of the MoS_(2)-HCS sphere is investigated in both supercapacitors and the hydrogen evolution reaction.
基金funding support from PhD Research Startup Foundation(ZKNUC2021017)Henan Province Science Foundation for Youth(242300420580)+1 种基金Key Scientific Research Projects of Colleges and Universities in Henan Province(24A530011)the funding support from National Natural Science Foundation of China(No.22108320,22268038).
文摘In the quest for amplifying the inherent capabilities of noble metals,crafting precise metal–support interfacial bonds stands as a challenging yet fruitful endeavor.Here,we introduce an approach to synthesize exceptionally small metal nanoparticles(NPs),which are securely anchored onto cobalt-based metal–organic framework(Co-MOF)nanosheets through a wet chemical method.The creation of metal–oxygen linkages between these Ir NPs and Co-MOF not only guarantees structural robustness but also ensures a generous exposure of active sites.Importantly,the distinct interface fine-tunes the electronic configuration of the composites by facilitating charge transfer along the Ir–O–Co pathway,consequently boosting the reaction dynamics.As a result,the hydrogen evolution reaction(HER)performance of our pioneering product,Ir@Co-MOF,in alkaline media,rivals that of the benchmark Pt/C catalyst and surpasses other recent noble metal catalysts.Theoretical analysis reveals that the exceptional HER efficiency of Ir@Co-MOF originates from the optimal adsorption energies for water and hydrogen,a consequence of electron re-allocation owing to its unique interfacial bond.
基金supported by the Science and Technology Major Project of Guangxi(AB16380030).
文摘Developing low-cost and efficient catalysts for hydrogen evolution is of great significance to solve the human energy crisis.In this work,ruthenium-nickel alloy is synthesized by a solvothermal method.The ruthenium-nickel alloy shows distinguished catalytic performance and durability for the hydrogen evolution reaction in alkaline solution(1 M KOH).Only 21,76,222 and 323 mV overpotentials are required to reach current densities of 10,100,1000 and 2000 mA cm^(-2).After 150 hours of a durability test at a current density of-400 mA cm^(-2),the alloy also shows outstanding durability.Density functional theory(DFT)further shows that ruthenium-nickel alloy composites can optimize the reaction barrier of alkaline hydrogen evolution.This study provides a valuable method for developing high-performance and lowprice alloy catalysts for hydrogen evolution.
基金supported by National Basic Research Program of China(2013CB934102)National Natural Science Foundation of China(21331004,21301116)SJTU-MPI partner group,SJTU-UM joint grant,Shanghai Eastern Scholar Program and Shanghai Rising-Star Program(16QA1402100).
文摘A highly active heterogeneous catalyst,Pd nanoparticles@g-C_(3)N_(4)/SiO_(2) with tunable band structure,was successfully fabricated by a sol–gel method.The nanocomposite catalyst exhibits an extraordinary hydrogen production rate from formic acid which leads to a high turnover frequency(TOF)of around 306 mol H_(2) per mole Pd per h after 10 min.The characterization analysis shows that the bandgap of the g-C_(3)N_(4)/SiO_(2) support widens with decreasing synthesis temperature,which in turn allows tuning of the band structure by simply controlling the synthesis temperature.After Pd nanoparticles were embedded,the nanocomposite Pd@g-C_(3)N_(4)/SiO_(2) showed excellent catalytic performance in the dehydrogenation of formic acid at 303.15 K,and the lower the synthesis temperature of the catalyst,the higher its performance.
基金National Natural Science Foundation of China(21571110)Natural Science Foundation of Zhejiang Province(LY18B010003)+1 种基金Ningbo Key Innovation Team(2014B81005)K.C.Wong Magna Fund in Ningbo University。
文摘Carbon anode materials for Li-ion batteries have been operated close to their theoretical rate and cycle limits.Therefore,titanium-based materials have attracted great attention due to their high stability.Here,Na_(2)Li_(2)Ti_(6)O_(14)nanofibers as anode materials were prepared through a controlled electrospinning method.The Na_(2)Li_(2)Ti_(6)O_(14)nanofibers presented superior electrochemical performance with high rate capability and long cycle life and can be regarded as a competitive anode candidate for advanced Li-ion batteries.One-dimensional(1D)Na_(2)Li_(2)Ti_(6)O_(14)nanofibers are able to deliver a capacity of 128.5 mA h g^(-1)at 0.5C,and demonstrate superior high-rate charge-discharge capability and cycling stability(the reversible charge capacity is 77.8 mA h g^(-1)with a capacity retention of 99.45%at the rate of 10C after 800 cycles).The 1D structure is considered to contribute remarkably to increased rate capability and stability.This simple and scalable method indicates that the Na_(2)Li_(2)Ti_(6)O_(14)nanofibers have a practical application potential for high performance lithium-ion batteries.
文摘In this paper,we report the highly selective and sensitive electrochemical determination of dopamine(DA)based on an iron oxide nanoparticle-(Fe_(2)O_(3)NP)capped graphene sheet(GRS)modified glassy carbon electrode(GCE).The Fe_(2)O_(3)NPs were synthesized by a pyrophoric technique and their nanocomposite with GRS was prepared by a simple sonochemical method.The as-prepared Fe_(2)O_(3)NP/GRS nanocomposite was characterized using scanning electron microscopy,electron dispersive X-ray spectroscopy,Raman spectroscopy,X-ray diffraction,Fourier transform infrared spectroscopy and electrochemical impedance spectroscopy.As expected,the proposed sensor exhibits a wide linear range from 0.01 to 195.18,a low detection limit(LOD)of 0.004μM for the DPV technique and a broad linear range from 0.006 to 635μM,and a very low detection limit of 0.001μM for the amperometric technique.Moreover,it shows excellent selectivity of DA even in the presence of a 20-fold higher concentration of potential interferences.The practical applicability of the reported sensor was recorded in human serum and urine samples.Finally,all electrochemical studies confirmed the excellent electrocatalytic activity of the Fe_(2)O_(3)NP/GRS nanocomposite as a DA sensor.
基金support from the National Natural Science Foundation of China(21471086,51572272)the Natural Science Foundation of Zhejiang Province(LQ18B070002)the K.C.Wong Magna Fund in Ningbo University.
文摘A hybrid core-shell material based on carbon nanofibers(CNFs)and a 2D conductive metal-organic framework(Ni-CAT)has been synthesized as a flexible free-standing membrane by combining electrospinning technology with a hydrothermal method.The as-made CNF@Ni-CAT exhibits a high specific capacitance of 502.95 F g^(-1)at a current density of 0.5 A g^(-1)and an improved cycling stability of 73%capacitance retention over 5000 cycles as an electrode material for supercapacitors due to its excellent synergistic effect.
基金supported by the National Natural Science Foundation of China(21872148)Natural Science Foundation of Fujian Province(2022J06031)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(Grant No.2021ZR131).
文摘The development of multiple metal-organic framework(MOF)thin films with high lattice mismatch is still a challenging task.Herein we report a series of single and multiple(bi-varietal and tri-varietal)pillarlayered MOF thin films(surface-coordinated MOF thin films,SURMOFs)[Cu_(2)L_(2)dabco]_(n)(L=bdc,bpc and tpdc)with preferred[001]-orientation on the substrate surfaces using a liquid-phase epitaxial(LPE)layer by layer pump method.The single SURMOFs with the same c-lattice parameters but different a-and b-lattice parameters result in the successful growth of oriented multiple SURMOFs with high lattice mismatch(up to 77.8%).The vapor adsorption results show that the representative bi-varietal SURMOF with large lattice mismatch has different adsorption behavior from single SURMOFs,providing a new strategy to achieve tuning of the adsorption kinetics performance in sensing applications.
基金financial support by NSFC(20971020,21073030 and 21131001)Program for New Century Excellent Talents in University(NCET-10-318)+1 种基金Doctoral Fund of Ministry of Education of China(20100043120007)the Science and Technology Development Planning of Jilin Province(20100104 and 20100320).
文摘The geometrical structures of Wells-Dawson derivatives[X-C(CH_(2)O)_(3)P_(2)M’_(3)M_(15)O_(59)]^(6-)(X=NO_(2),NH_(2),and CH_(3),M’=V and Nb,M=W and Mo)have been calculated by the density functional theory(DFT)method.The results show that the distances of P…P and P…C are controlled by the{M’_(3)}triads,and{M’_(3)}triads also affect the sizes of W_(6) hexagonal belts.The second-order polarizabilities and origin of nonlinear optical(NLO)properties of those clusters have been investigated by a time-dependent density functional theory(TDDFT)method.The NLO property analysis reveals that[X-C(CH_(2)O)3P_(2)V_(3)Mo_(15)O_(59)]^(6-)(X=NH_(2))anions have the largest β_(vec) values,75.064×10^(-30) esu.Grafting electron donors to POM clusters is an efficient way to improve the NLO response.The major electron transition orbitals show that the charge transfer from the organic groups to the metal atoms is responsible for the NLO properties of these polyoxometalates.
基金supported by the National Key Research and Development Program of China(2016YFB0901503)the Nature Science Foundation of the Jiangsu Higher Education Institutions(No.19KJB150025)+1 种基金the National Natural Science Foundation of China(21875238)the Entrepreneurship and Innovation Program of Jiangsu Province.
文摘MoSe_(2) has been recognized as a promising anode material for lithium/sodium ion batteries due to its unique structure and material properties.Here,hierarchical MoSe_(2)@C hollow nanospheres(MoSe_(2)@C HNSs)assembled with ultrathin nanosheets are prepared via a facile solvothermal method.The MoSe_(2)@C HNS composite is fabricated by an anion-exchange reaction from Mo-glycerate solid spheres combining with the carbonization of glucose.When used as an anode material for LIBs,the MoSe_(2)@C HNS composite manifests a reversible capacity of 711 mA h g^(−1) after 300 cycles under a current density of 500 mA g^(−1).When evaluated as an anode material for SIBs,the MoSe_(2)@C HNS composite delivers a high capacity of 683 mA h g^(−1) at 100 mA g^(−1) and maintains a capacity of 458 mA h g^(−1) after 200 cycles at 200 mA g^(−1).The efficient lithium and sodium ion storage performance should be ascribed to the unique hierarchical hollow nanostructure and synchronously incorporated carbon material.
基金financial support by the NSF of China(21271038,21571032,21071027)the China High-Tech Development 863 Program(2007AA03Z218)and the analysis and testing platform of Northeast Normal University.
文摘The Lindqvist anion[Mo_(6)O_(19)]^(2−)was in situ intercalated into layered double hydroxides(LDHs)via a onepot hydrothermal method.The heterogeneous catalyst was applied in ultra-deep desulfurization of fuels under mild conditions,and exhibited high activity for dibenzothiophene(DBT),benzothiophene(BT)and 4,6-dimethyldibenzothiophene(4,6-DMDBT).The above sulfur-containing compounds could be completely transformed into their corresponding sulfones under the stoichiometric O/S molar ratio(O/S molar ratio=2).Furthermore,the catalyst could be easily recovered and reused at least 7 times without an obvious decrease in performance.The possible desulfurization mechanism was also studied in detail.
基金supported by the Ministry of Science and Technology,Taiwan,ROC under the grant MOST 106-2221-E-027-107.
文摘A novel electrochemical sensor based on a graphene oxide(GO)/three-dimensional(3D)hierarchical zinc oxide(ZnO)nanocomposite was developed for the efficient determination of the antibiotic drug chloramphenicol(CAP).The hierarchical ZnO structure consisting of nanosheets was synthesized by a green aqueous solution procedure and then composited with GO through a simple sonochemical method.The synthesized ZnO and GO/ZnO nanomaterials were characterized by scanning electron microscopy(SEM),elemental mapping,X-ray diffraction(XRD),UV-Visible spectroscopy,Fourier transform infrared spectroscopy(FT-IR),and Raman spectroscopy.The electrochemical performance of the prepared GO/ZnO/glassy carbon electrode(GCE)was evaluated using cyclic voltammetry(CV)and differential pulse voltammetry(DPV)techniques.The GO/ZnO/GCE shows a low CAP detection limit of 0.01μM,a high sensitivity of 7.27μAμM^(−1) cm^(−2),and a linear response in the range of 0.2 to 7.2μM.Moreover,it exhibits excellent stability,reproducibility and repeatability.Practicality of the sensor has further been demonstrated with honey,milk and eye drop samples.
