An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the mag...An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.展开更多
In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode mater...In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode material for lithium ion batteries. The novel synthesis of the MnO/CoMn_2O_4 GN consists of thermal decomposition of metal–oleate complex containing cobalt and manganese metals and oleate ligand, forming bimetallic oxides nanoparticles, followed by a selfassembly route with reduced graphene oxides. The MnO/CoMn_2O_4 GN composite, with a unique architecture of bimetallic oxides nanoparticles encapsulated in 3D graphene networks, rationally integrates several benefits including shortening the di usion path of Li^+ ions, improving electrical conductivity and mitigating volume variation during cycling. Studies show that the electrochemical reaction processes of MnO/Co Mn_2O_4 GN electrodes are dominated by the pseudocapacitive behavior, leading to fast Li^+ charge/discharge reactions. As a result, the MnO/CoMn_2O_4 GN manifests high initial specific capacity, stable cycling performance, and excellent rate capability.展开更多
As one of prussian blue analogues,Co_(3)[Co(CN)_(6)]_(2) has been explored as a promising anode material for potassium-ion batteries(PIBs) owing to its high potassium storage capacity.Unfortunately,Co_(3)[Co(CN)_(6)]_...As one of prussian blue analogues,Co_(3)[Co(CN)_(6)]_(2) has been explored as a promising anode material for potassium-ion batteries(PIBs) owing to its high potassium storage capacity.Unfortunately,Co_(3)[Co(CN)_(6)]_(2) possesses low electronic conductivity and its structure collapses easily during potassiation and depotassiation,resulting in poor rate performance and cyclic stability.To solve these problems,we develop a facile multi-step method to successfully combine uniformCo_(3)[Co(CN)_(6)]_(2) nanocubes with rGO by C-O-Co bonds.As expected,these chemcial bonds shorten the distance betweenCo_(3)[Co(CN)_(6)]_(2) and rGO to the angstrom meter level,which significantly improve the electronic conductivity ofCo_(3)[Co(CN)_(6)]_(2).Besides,the complete encapsulation ofCo_(3)[Co(CN)_(6)]_(2) nanocubes by rGO endows the structure ofCo_(3)[Co(CN)_(6)]_(2) with high stability,thus withstanding repeated insertion/extraction of potassium-ions without visible morphological and structural changes.Benefiting from the abovementioned structural advantages,the CO3 [Co(CN)6]2/rGO nanocomposite exhibits a high reversible capacity of 400.8 mAh g^(-1) at a current density of 0.1 A g^(-1),an exceptional rate capability of 115.5 mAh g^(-1) at 5 A g^(-1), and an ultralong cycle life of 231.9 mAh g^(-1) at 0.1 A g^(-1) after 1000 cycles.Additionally,the effects of different amounts of rGO and different sizes ofCo_(3)[Co(CN)_(6)]_(2) nanocubes on the potassium storage performance are also studied.This work offers an ideal route to significantly enhance the electrochemical properties of prussian blue analogues.展开更多
By using a reflective graphene oxide as saturable absorber, a diode-pumped passively mode-locked Yb^3＋：Sc2Si O5（Yb：SSO） laser has been demonstrated for the first time. Without extra negative dispersion compensati...By using a reflective graphene oxide as saturable absorber, a diode-pumped passively mode-locked Yb^3＋：Sc2Si O5（Yb：SSO） laser has been demonstrated for the first time. Without extra negative dispersion compensation, the minimum pulse duration of 1.7 ps with a repetition rate of 94 MHz was obtained at the central wavelength of 1062.6 nm. The average output power amounts to 355 m W under the absorbed pump power of 15 W. The maximum peak power of the mode-locking laser is up to 2.2 k W, and the single pulse energy is 3.8nJ.展开更多
Nano 3C-SiC@multilayer graphene oxide(NS@MGO)heterostructure was in situ prepared by carbothermal reduction of pyrolyzed precursor composed of highly dispersed cured phenolic resin and silicon dioxide derived from tet...Nano 3C-SiC@multilayer graphene oxide(NS@MGO)heterostructure was in situ prepared by carbothermal reduction of pyrolyzed precursor composed of highly dispersed cured phenolic resin and silicon dioxide derived from tetraethyl orthosilicate.The heterojunction interface,number of layers of MGO,and defect content in graphene are the three most important factors for promoting photocatalytic activity.Direct contact between 3C-SiC nanograins and MGO layers facilitates the photogenerated electrons to migrate across the heterojunction interface and avoid the formation of SiO_(2) nanolayers on the surface of SiC nanograins.The number of MGO layers is supposed to be less than ten instead of over-thick MGO.The concentrations of oxygenated components,considered the defect contents,decrease with the increase of sintering temperature for NS@MGO 0.175-T-150,and relative carbon content in the multilayer graphene increases.According to the heterostructures,properties,and photocatalytic reaction performance of the NS@MGO materials,the highest photocatalytic kinetic rate constant of 0.00891/min for NS@MGO 0.175-1500-150 shows that the significant enhancement in photocatalytic degradation activity under visible light(>420 nm)irradiation is ascribed to the advantageous synergistic effects between the nano 3C-SiC particles and the direct contact multilayer graphene oxide with appropriate layers and sufficient oxygen content of 3.51%(atomic fraction)in MGO.展开更多
Direct methanol fuel cell technology recently becomes the focus of both academic and engineering circles,which stimulates the exploitation and utilization of advanced electrode catalysts with high activity and long li...Direct methanol fuel cell technology recently becomes the focus of both academic and engineering circles,which stimulates the exploitation and utilization of advanced electrode catalysts with high activity and long lifespan.Herein,we demonstrate a robust bottom-up approach to the spatial construction of three-dimensional(3D) spinel manganese-cobalt oxide-modified N-doped graphene nanoarchitectures decorated with ultrasmall Pt nanoparticles(Pt/MnCo_(2)O_(4)-NG) via a controllable selfassembly process.The incorporation of MnCo_(2)O_(4)nanocrystals provides abundant hydroxyl sources to promote the oxidative removal of CO-like byproducts on Pt sites,while the existence of 3D porous N-doped graphene networks facilitates the transportation of both ions and electrons in the hybrid system,thus giving rise to remarkable synergetic coupling effects during the methanol oxidation process.Consequently,the optimized Pt/MnCo_(2)O_(4)-NG nano architecture expres ses exceptional electrocatalytic properties with a large electrochemically active surface area of 99.5 m^(2)·g^(-1),a high mass activity of1508.3 mA·mg^(-1),strong toxicity resistance and reliable long-term durability,which have obvious competitive advantages over those of conventional Pt/carbon black,Pt/carbon nano tube,Pt/graphene,and Pt/N-doped graphene catalysts with the same Pt usage.展开更多
Bi_(2)O_(2)CO_(3)(BOC)/Bi_(4)O_5Br_(2)(BOB)/reduced graphene oxide(rGO)Z-scheme heterojunction with promising photocatalytic properties was synthesized via a facile one-pot room-temperature method.Ultra-thin nanosheet...Bi_(2)O_(2)CO_(3)(BOC)/Bi_(4)O_5Br_(2)(BOB)/reduced graphene oxide(rGO)Z-scheme heterojunction with promising photocatalytic properties was synthesized via a facile one-pot room-temperature method.Ultra-thin nanosheets of BOC and BOB were grown in situ on r GO.The formed 2D/2D direct Z-scheme heterojunction of BOC/BOB with oxygen vacancies(OVs)effectively leads to lower negative electron reduction potential of BOB as well as higher positive hole oxidation potential of BOC,showing improved reduction/oxidation ability.Particularly,rGO is an acceptor of the electrons from the conduction band of BOC.Its dual roles significantly improve the transfer performance of photo-induced charge carriers and accelerate their separation.With layered nanosheet structure,rich OVs,high specific surface area,and increased utilization efficiency of visible light,the multiple synergistic effects of BOC/BOB/rGO can achieve effective generation and separation of the electron-holes,thereby generating more·O_(2)^(-)and h^(+).The photocatalytic reduction efficiency of CO_(2)to CO(12.91μmol/(g·hr))is three times higher than that of BOC(4.18μmol/(g·hr)).Moreover,it also achieved almost 100%removal of Rhodamine B and cyanobacterial cells within 2 hours.展开更多
Considering the serious electromagnetic wave(EMW)pollution problems and complex application condition,there is a pressing need to amalgamate multiple functionalities within a single substance.However,the effective int...Considering the serious electromagnetic wave(EMW)pollution problems and complex application condition,there is a pressing need to amalgamate multiple functionalities within a single substance.However,the effective integration of diverse functions into designed EMW absorption materials still faces the huge challenges.Herein,reduced graphene oxide/carbon foams(RGO/CFs)with two-dimensional/three-dimensional(2D/3D)van der Waals(vdWs)heterostructures were meticulously engineered and synthesized utilizing an efficient methodology involving freeze-drying,immersing absorption,secondary freeze-drying,followed by carbonization treatment.Thanks to their excellent linkage effect of amplified dielectric loss and optimized impedance matching,the designed 2D/3D RGO/CFs vdWs heterostructures demonstrated commendable EMW absorption performances,achieving a broad absorption bandwidth of 6.2 GHz and a reflection loss of-50.58 dB with the low matching thicknesses.Furthermore,the obtained 2D/3D RGO/CFs vdWs heterostructures also displayed the significant radar stealth properties,good corrosion resistance performances as well as outstanding thermal insulation capabilities,displaying the great potential in complex and variable environments.Accordingly,this work not only demonstrated a straightforward method for fabricating 2D/3D vdWs heterostructures,but also outlined a powerful mixeddimensional assembly strategy for engineering multifunctional foams for electromagnetic protection,aerospace and other complex conditions.展开更多
In_(2)O_(3)is an effective electrocatalyst to convert CO_(2)to formic acid(HCOOH),but its inherent poor electrical conductivity limits the efficient charge transfer during the reaction.Additionally,the tendency of In_...In_(2)O_(3)is an effective electrocatalyst to convert CO_(2)to formic acid(HCOOH),but its inherent poor electrical conductivity limits the efficient charge transfer during the reaction.Additionally,the tendency of In_(2)O_(3)particles to agglomerate during synthesis further limits the exposure of active sites.Here we address these issues by leveraging the template effect of graphene oxide and employing InBDC as a self-sacrificing template for the pyrolysis synthesis of In_(2)O_(3)@C.The resulting In_(2)O_(3)@C/rGO-600 material features In_(2)O_(3)@C nanocubes uniformly anchored on a support of reduced graphene oxide(rGO),significantly enhancing the active sites exposure.The conductive rGO network facilitates charge transfer during electrocatalysis,and the presence of oxygen vacancies generated during pyrolysis,combined with the strong electron-donating ability of rGO,enhances the adsorption and activation of CO_(2).In performance evaluation,In_(2)O_(3)@C/rGO-600 exhibits a remarkable HCOOH Faradaic efficiency exceeding 94.0%over a broad potential window of−0.7 to−1.0 V(vs.reversible hydrogen electrode(RHE)),with the highest value of 97.9%at−0.9 V(vs.RHE)in a H-cell.Moreover,the material demonstrates an excellent cathodic energy efficiency of 71.6%at−0.7 V(vs.RHE).The study underscores the efficacy of uniformly anchoring metal oxide nanoparticles onto rGO for enhancing the electrocatalytic CO_(2)reduction performance of materials.展开更多
Beyond the traditional focus on improvements in mechanical, electronic and absorption properties, controllability, actuation, and dynamic response of monoliths have received increasing attentions for practical applica...Beyond the traditional focus on improvements in mechanical, electronic and absorption properties, controllability, actuation, and dynamic response of monoliths have received increasing attentions for practical applications. However, most of them could only realize simple response to constant conditions(e.g. a stationary magnetic field) while carrying out humdrum motions. By controlling distribution of metal organic framework obtained carbon-enriched Fe304 nanoparticles in self-assembly reduced graphene oxide(RGO) monoliths, we could achieve two distinctive RGO-Fe_3 O_4 stirrers that could dynamically respond to the rapidly changing magnetic field while executing designed movements precisely: rotating with lying down posture or standing straight posture. These stirrers can not only be applied in environmental remediation(e.g.suction skimmer), but also be recycled as electrode active materials for supercapacitors after fulfilling their destiny, realizing transformation of trash to treasure, which will inspire other dynamically responsive monoliths for various applications.展开更多
The custom-tailored medicine requires a developmental strategy that integrates excellent osteogene-sis with mechanical stability to enhance the reconstruction of the critical-size bone defect(CSBD)and the healing proc...The custom-tailored medicine requires a developmental strategy that integrates excellent osteogene-sis with mechanical stability to enhance the reconstruction of the critical-size bone defect(CSBD)and the healing process in weight-bearing bone.We prepared three-dimensional(3D)printed biphasic cal-cium phosphate(BCP)scaffolds composited with nano-graphene oxide(GO).The biological effects of the GO/BCP composite scaffolds could induce the differentiation of rat bone marrow stem cells(BM-SCs)and the migration of human umbilical vein endothelial cells(HUVECs)for bone repair.The proper ratio of GO in the composite scaffold regulated the composites’surface roughness and hydrophilicity to a suitable range for the adhesion and proliferation of BMSCs and HUVECs.Besides,the GO/BCP composite scaffold increased osteogenesis and angiogenesis by activating BMP-2,RUNX-2,Smad1/4,and VEGF.The customized intramedullary nail combined with GO/BCP scaffold was applied to repair CSBD(2.0 cm in length)in a beagle femur model.This fixation strategy was confirmed by finite element analysis.In vivo,the results indicated that the custom-made internal fixation provided sufficient stability in the early stage,ensuring bone healing in a considerable mechanical environment.At 9 months postoperatively,longitudi-nal bony union and blood vessels in osteon were observed in the CSBD area with partial degradation in the 0.3%GO/BCP group.In the three-point bending test,the ultimate load of 0.3%GO/BCP group reached over 50%of the normal femur at 9 months after repair.These results showed a promising application of osteogenic GO/BCP scaffold and custom-made intramedullary nails in repairing CSBD of the beagle femur.This effective strategy could provide an option to treat the clinical CSBD in weight-bearing bones.展开更多
Energy crises and environmental pollution have become urgent problems with human civilization development.Photocatalysis technology is a green method to deal with these challenges.The key to improve photocatalytic eff...Energy crises and environmental pollution have become urgent problems with human civilization development.Photocatalysis technology is a green method to deal with these challenges.The key to improve photocatalytic efficiency lies in the effective separation of photogenerated electron-hole pairs.In this work,we designed the Fe atom embedded N-doped graphene oxide(Fe-NGO)supporting on tantalum nitride(Ta_(3)N_(5))catalyst,which was employed to improve the photocatalytic oxygen production activity.The oxygen production of 5 wt%Fe atom embedded N-doped graphene oxide supporting on tantalum nitride(Fe-NGO/Ta_(3)N_(5))was 184.7μmol·g^(-1),about 3.5 times higher than that of the pure Ta_(3)N_(5).The introduction of the cocatalyst Fe-NGO acting as an electron conductor in the Fe-NGO/Ta_(3)N_(5) accelerates the carrier migration of Ta_(3)N_(5) and further enhances the photocatalytic oxygen production activity.N-doping increases the conductivity of graphene oxide(GO),and Fe atoms are used as the reactive sites to promote the combination of electron and sacrificial agent in the system.This work may provide insights into the research of new carbon.展开更多
We report the preparation of nanocomposites of reduced graphene oxide with embedded Fe3O4/Fe nanorings （FeNR@rGO） by chemical hydrothermal growth. We illustrate the use of these nanocomposites as novel electromagnet...We report the preparation of nanocomposites of reduced graphene oxide with embedded Fe3O4/Fe nanorings （FeNR@rGO） by chemical hydrothermal growth. We illustrate the use of these nanocomposites as novel electromagnetic wave absorbing materials. The electromagnetic wave absorption properties of the nanocomposites with different compositions were investigated. The preparation procedure and nanocomposite composition were optimized to achieve the best electromagnetic wave absorption properties. Nanocomposites with a GO：cx-Fe203 mass ratio of 1：1 prepared by annealing in HdAr for 3 h exhibited the best properties. This nanocomposite sample （thickness = 4.0 mm） showed a minimum reflectivity of -23.09 dB at 9.16 GHz. The band range was 7.4-11.3 GHz when the reflectivity was less than -10 dB and the spectrum width was up to 3.9 GHz. These figures of merit are typically of the same order of magnitude when compared to the values shown by traditional ferric oxide materials. However, FeNR@rGO can be readily applied as a microwave absorbing material because the production method we propose is highly compatible with mass production standards.展开更多
基金supported by the National Natural Science Foundation of China (21373138)Shanghai Sci. & Tech. Committee (12JC1407200)Program for Changjiang Scholars and Innovative Research Team in University (IRT1269)
文摘An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.
基金financial support from National Natural Science Foundation of China (No. 21373006 and No. 51801030)the Science and Technology Program of Suzhou (SYG201732)+4 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the project of Scientific and Technologic Infrastructure of Suzhou (SZS201708)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (17KJB430029)One-hundred Young Talents (Class A) of Guangdong University of Technology (No. 220413198)Natural Science Foundation of Guangdong Providence (No. 2018A030310571)
文摘In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode material for lithium ion batteries. The novel synthesis of the MnO/CoMn_2O_4 GN consists of thermal decomposition of metal–oleate complex containing cobalt and manganese metals and oleate ligand, forming bimetallic oxides nanoparticles, followed by a selfassembly route with reduced graphene oxides. The MnO/CoMn_2O_4 GN composite, with a unique architecture of bimetallic oxides nanoparticles encapsulated in 3D graphene networks, rationally integrates several benefits including shortening the di usion path of Li^+ ions, improving electrical conductivity and mitigating volume variation during cycling. Studies show that the electrochemical reaction processes of MnO/Co Mn_2O_4 GN electrodes are dominated by the pseudocapacitive behavior, leading to fast Li^+ charge/discharge reactions. As a result, the MnO/CoMn_2O_4 GN manifests high initial specific capacity, stable cycling performance, and excellent rate capability.
基金supported by the National Natural Science Foundation of China(51577094)the Natural Science Foundation of Jiangsu Province of China(BK20180086)。
文摘As one of prussian blue analogues,Co_(3)[Co(CN)_(6)]_(2) has been explored as a promising anode material for potassium-ion batteries(PIBs) owing to its high potassium storage capacity.Unfortunately,Co_(3)[Co(CN)_(6)]_(2) possesses low electronic conductivity and its structure collapses easily during potassiation and depotassiation,resulting in poor rate performance and cyclic stability.To solve these problems,we develop a facile multi-step method to successfully combine uniformCo_(3)[Co(CN)_(6)]_(2) nanocubes with rGO by C-O-Co bonds.As expected,these chemcial bonds shorten the distance betweenCo_(3)[Co(CN)_(6)]_(2) and rGO to the angstrom meter level,which significantly improve the electronic conductivity ofCo_(3)[Co(CN)_(6)]_(2).Besides,the complete encapsulation ofCo_(3)[Co(CN)_(6)]_(2) nanocubes by rGO endows the structure ofCo_(3)[Co(CN)_(6)]_(2) with high stability,thus withstanding repeated insertion/extraction of potassium-ions without visible morphological and structural changes.Benefiting from the abovementioned structural advantages,the CO3 [Co(CN)6]2/rGO nanocomposite exhibits a high reversible capacity of 400.8 mAh g^(-1) at a current density of 0.1 A g^(-1),an exceptional rate capability of 115.5 mAh g^(-1) at 5 A g^(-1), and an ultralong cycle life of 231.9 mAh g^(-1) at 0.1 A g^(-1) after 1000 cycles.Additionally,the effects of different amounts of rGO and different sizes ofCo_(3)[Co(CN)_(6)]_(2) nanocubes on the potassium storage performance are also studied.This work offers an ideal route to significantly enhance the electrochemical properties of prussian blue analogues.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61078032,61378024,60938001,and 61078053)the Science and Technology Development Projects of Shandong Province,China(Grant No.2013GGX10108)
文摘By using a reflective graphene oxide as saturable absorber, a diode-pumped passively mode-locked Yb^3＋：Sc2Si O5（Yb：SSO） laser has been demonstrated for the first time. Without extra negative dispersion compensation, the minimum pulse duration of 1.7 ps with a repetition rate of 94 MHz was obtained at the central wavelength of 1062.6 nm. The average output power amounts to 355 m W under the absorbed pump power of 15 W. The maximum peak power of the mode-locking laser is up to 2.2 k W, and the single pulse energy is 3.8nJ.
基金This work was supported by the National Key Research and Development Program of China(No.2021YFB3801301)the Shenyang National Laboratory for Materials Science(SYNL,China)Program for Youth Talent(No.L2022F39).
文摘Nano 3C-SiC@multilayer graphene oxide(NS@MGO)heterostructure was in situ prepared by carbothermal reduction of pyrolyzed precursor composed of highly dispersed cured phenolic resin and silicon dioxide derived from tetraethyl orthosilicate.The heterojunction interface,number of layers of MGO,and defect content in graphene are the three most important factors for promoting photocatalytic activity.Direct contact between 3C-SiC nanograins and MGO layers facilitates the photogenerated electrons to migrate across the heterojunction interface and avoid the formation of SiO_(2) nanolayers on the surface of SiC nanograins.The number of MGO layers is supposed to be less than ten instead of over-thick MGO.The concentrations of oxygenated components,considered the defect contents,decrease with the increase of sintering temperature for NS@MGO 0.175-T-150,and relative carbon content in the multilayer graphene increases.According to the heterostructures,properties,and photocatalytic reaction performance of the NS@MGO materials,the highest photocatalytic kinetic rate constant of 0.00891/min for NS@MGO 0.175-1500-150 shows that the significant enhancement in photocatalytic degradation activity under visible light(>420 nm)irradiation is ascribed to the advantageous synergistic effects between the nano 3C-SiC particles and the direct contact multilayer graphene oxide with appropriate layers and sufficient oxygen content of 3.51%(atomic fraction)in MGO.
基金financially supported by the National Natural Science Foundation of China (Nos.22209037 and 51802077)the Fundamental Research Funds for the Central Universities (No.B220202042)。
文摘Direct methanol fuel cell technology recently becomes the focus of both academic and engineering circles,which stimulates the exploitation and utilization of advanced electrode catalysts with high activity and long lifespan.Herein,we demonstrate a robust bottom-up approach to the spatial construction of three-dimensional(3D) spinel manganese-cobalt oxide-modified N-doped graphene nanoarchitectures decorated with ultrasmall Pt nanoparticles(Pt/MnCo_(2)O_(4)-NG) via a controllable selfassembly process.The incorporation of MnCo_(2)O_(4)nanocrystals provides abundant hydroxyl sources to promote the oxidative removal of CO-like byproducts on Pt sites,while the existence of 3D porous N-doped graphene networks facilitates the transportation of both ions and electrons in the hybrid system,thus giving rise to remarkable synergetic coupling effects during the methanol oxidation process.Consequently,the optimized Pt/MnCo_(2)O_(4)-NG nano architecture expres ses exceptional electrocatalytic properties with a large electrochemically active surface area of 99.5 m^(2)·g^(-1),a high mass activity of1508.3 mA·mg^(-1),strong toxicity resistance and reliable long-term durability,which have obvious competitive advantages over those of conventional Pt/carbon black,Pt/carbon nano tube,Pt/graphene,and Pt/N-doped graphene catalysts with the same Pt usage.
基金supported by the National Natural Science Foundation of China(Nos.51602281 and 52100014)the Natural Science Foundation of Jiangsu Province(No.BK20180938)the Yangzhou University High-end Talent Support Program and the“Qinglan Project”of Jiangsu Universities。
文摘Bi_(2)O_(2)CO_(3)(BOC)/Bi_(4)O_5Br_(2)(BOB)/reduced graphene oxide(rGO)Z-scheme heterojunction with promising photocatalytic properties was synthesized via a facile one-pot room-temperature method.Ultra-thin nanosheets of BOC and BOB were grown in situ on r GO.The formed 2D/2D direct Z-scheme heterojunction of BOC/BOB with oxygen vacancies(OVs)effectively leads to lower negative electron reduction potential of BOB as well as higher positive hole oxidation potential of BOC,showing improved reduction/oxidation ability.Particularly,rGO is an acceptor of the electrons from the conduction band of BOC.Its dual roles significantly improve the transfer performance of photo-induced charge carriers and accelerate their separation.With layered nanosheet structure,rich OVs,high specific surface area,and increased utilization efficiency of visible light,the multiple synergistic effects of BOC/BOB/rGO can achieve effective generation and separation of the electron-holes,thereby generating more·O_(2)^(-)and h^(+).The photocatalytic reduction efficiency of CO_(2)to CO(12.91μmol/(g·hr))is three times higher than that of BOC(4.18μmol/(g·hr)).Moreover,it also achieved almost 100%removal of Rhodamine B and cyanobacterial cells within 2 hours.
基金provided by Guizhou Provincial Science and Technology Projects for Platform and Talent Team Plan(GCC[2023]007)Fok Ying Tung Education Foundation(171095)National Natural Science Foundation of China(11964006).
文摘Considering the serious electromagnetic wave(EMW)pollution problems and complex application condition,there is a pressing need to amalgamate multiple functionalities within a single substance.However,the effective integration of diverse functions into designed EMW absorption materials still faces the huge challenges.Herein,reduced graphene oxide/carbon foams(RGO/CFs)with two-dimensional/three-dimensional(2D/3D)van der Waals(vdWs)heterostructures were meticulously engineered and synthesized utilizing an efficient methodology involving freeze-drying,immersing absorption,secondary freeze-drying,followed by carbonization treatment.Thanks to their excellent linkage effect of amplified dielectric loss and optimized impedance matching,the designed 2D/3D RGO/CFs vdWs heterostructures demonstrated commendable EMW absorption performances,achieving a broad absorption bandwidth of 6.2 GHz and a reflection loss of-50.58 dB with the low matching thicknesses.Furthermore,the obtained 2D/3D RGO/CFs vdWs heterostructures also displayed the significant radar stealth properties,good corrosion resistance performances as well as outstanding thermal insulation capabilities,displaying the great potential in complex and variable environments.Accordingly,this work not only demonstrated a straightforward method for fabricating 2D/3D vdWs heterostructures,but also outlined a powerful mixeddimensional assembly strategy for engineering multifunctional foams for electromagnetic protection,aerospace and other complex conditions.
基金Joint Key Program of National Natural Science Foundation of China(No.U22B20147).
文摘In_(2)O_(3)is an effective electrocatalyst to convert CO_(2)to formic acid(HCOOH),but its inherent poor electrical conductivity limits the efficient charge transfer during the reaction.Additionally,the tendency of In_(2)O_(3)particles to agglomerate during synthesis further limits the exposure of active sites.Here we address these issues by leveraging the template effect of graphene oxide and employing InBDC as a self-sacrificing template for the pyrolysis synthesis of In_(2)O_(3)@C.The resulting In_(2)O_(3)@C/rGO-600 material features In_(2)O_(3)@C nanocubes uniformly anchored on a support of reduced graphene oxide(rGO),significantly enhancing the active sites exposure.The conductive rGO network facilitates charge transfer during electrocatalysis,and the presence of oxygen vacancies generated during pyrolysis,combined with the strong electron-donating ability of rGO,enhances the adsorption and activation of CO_(2).In performance evaluation,In_(2)O_(3)@C/rGO-600 exhibits a remarkable HCOOH Faradaic efficiency exceeding 94.0%over a broad potential window of−0.7 to−1.0 V(vs.reversible hydrogen electrode(RHE)),with the highest value of 97.9%at−0.9 V(vs.RHE)in a H-cell.Moreover,the material demonstrates an excellent cathodic energy efficiency of 71.6%at−0.7 V(vs.RHE).The study underscores the efficacy of uniformly anchoring metal oxide nanoparticles onto rGO for enhancing the electrocatalytic CO_(2)reduction performance of materials.
基金supported by Natural Science Foundation of SZU (Grant No. 2017004)Early Career Scheme of the Research Grants Council of Hong Kong SAR, China, under the Project No. CityU 109213a Grant from the City University of Hong Kong (9610372)
文摘Beyond the traditional focus on improvements in mechanical, electronic and absorption properties, controllability, actuation, and dynamic response of monoliths have received increasing attentions for practical applications. However, most of them could only realize simple response to constant conditions(e.g. a stationary magnetic field) while carrying out humdrum motions. By controlling distribution of metal organic framework obtained carbon-enriched Fe304 nanoparticles in self-assembly reduced graphene oxide(RGO) monoliths, we could achieve two distinctive RGO-Fe_3 O_4 stirrers that could dynamically respond to the rapidly changing magnetic field while executing designed movements precisely: rotating with lying down posture or standing straight posture. These stirrers can not only be applied in environmental remediation(e.g.suction skimmer), but also be recycled as electrode active materials for supercapacitors after fulfilling their destiny, realizing transformation of trash to treasure, which will inspire other dynamically responsive monoliths for various applications.
基金This work was financially supported,in part,by the Sci-ence and Technology Research Program of Sichuan Province(No.2020YFS0036,Dr.Tu)the 1·3·5 project for disciplines of excel-lence,West China Hospital,Sichuan University(No.ZYJC18036,Dr.Tu).
文摘The custom-tailored medicine requires a developmental strategy that integrates excellent osteogene-sis with mechanical stability to enhance the reconstruction of the critical-size bone defect(CSBD)and the healing process in weight-bearing bone.We prepared three-dimensional(3D)printed biphasic cal-cium phosphate(BCP)scaffolds composited with nano-graphene oxide(GO).The biological effects of the GO/BCP composite scaffolds could induce the differentiation of rat bone marrow stem cells(BM-SCs)and the migration of human umbilical vein endothelial cells(HUVECs)for bone repair.The proper ratio of GO in the composite scaffold regulated the composites’surface roughness and hydrophilicity to a suitable range for the adhesion and proliferation of BMSCs and HUVECs.Besides,the GO/BCP composite scaffold increased osteogenesis and angiogenesis by activating BMP-2,RUNX-2,Smad1/4,and VEGF.The customized intramedullary nail combined with GO/BCP scaffold was applied to repair CSBD(2.0 cm in length)in a beagle femur model.This fixation strategy was confirmed by finite element analysis.In vivo,the results indicated that the custom-made internal fixation provided sufficient stability in the early stage,ensuring bone healing in a considerable mechanical environment.At 9 months postoperatively,longitudi-nal bony union and blood vessels in osteon were observed in the CSBD area with partial degradation in the 0.3%GO/BCP group.In the three-point bending test,the ultimate load of 0.3%GO/BCP group reached over 50%of the normal femur at 9 months after repair.These results showed a promising application of osteogenic GO/BCP scaffold and custom-made intramedullary nails in repairing CSBD of the beagle femur.This effective strategy could provide an option to treat the clinical CSBD in weight-bearing bones.
基金support from the National Natural Science Foundation of China (Nos.22106053,22008095)the China Postdoctoral Science Foundation (Nos.2021M691305,2020TQ0127)the Jiangsu Province Postdoctoral Science Foundation (Nos.2021K079A,2021K396C,2021K382C).
文摘Energy crises and environmental pollution have become urgent problems with human civilization development.Photocatalysis technology is a green method to deal with these challenges.The key to improve photocatalytic efficiency lies in the effective separation of photogenerated electron-hole pairs.In this work,we designed the Fe atom embedded N-doped graphene oxide(Fe-NGO)supporting on tantalum nitride(Ta_(3)N_(5))catalyst,which was employed to improve the photocatalytic oxygen production activity.The oxygen production of 5 wt%Fe atom embedded N-doped graphene oxide supporting on tantalum nitride(Fe-NGO/Ta_(3)N_(5))was 184.7μmol·g^(-1),about 3.5 times higher than that of the pure Ta_(3)N_(5).The introduction of the cocatalyst Fe-NGO acting as an electron conductor in the Fe-NGO/Ta_(3)N_(5) accelerates the carrier migration of Ta_(3)N_(5) and further enhances the photocatalytic oxygen production activity.N-doping increases the conductivity of graphene oxide(GO),and Fe atoms are used as the reactive sites to promote the combination of electron and sacrificial agent in the system.This work may provide insights into the research of new carbon.
基金This work was supported by the National Basic Research Program of China （No. 2013CB932602）, the Program of Introducing Talents of Discipline to Universities （No. B14003）, National Natural Science Foundation of China （No. 51527802, 51372020 and 51232001）, Beijing Municipal Science ＆ Technology Commission, Beijing Higher Education Young Elite Teacher Project （No. YETP0354）, Program for New Century Excellent Talents in University （No. NCET- 12-0777）.
文摘We report the preparation of nanocomposites of reduced graphene oxide with embedded Fe3O4/Fe nanorings （FeNR@rGO） by chemical hydrothermal growth. We illustrate the use of these nanocomposites as novel electromagnetic wave absorbing materials. The electromagnetic wave absorption properties of the nanocomposites with different compositions were investigated. The preparation procedure and nanocomposite composition were optimized to achieve the best electromagnetic wave absorption properties. Nanocomposites with a GO：cx-Fe203 mass ratio of 1：1 prepared by annealing in HdAr for 3 h exhibited the best properties. This nanocomposite sample （thickness = 4.0 mm） showed a minimum reflectivity of -23.09 dB at 9.16 GHz. The band range was 7.4-11.3 GHz when the reflectivity was less than -10 dB and the spectrum width was up to 3.9 GHz. These figures of merit are typically of the same order of magnitude when compared to the values shown by traditional ferric oxide materials. However, FeNR@rGO can be readily applied as a microwave absorbing material because the production method we propose is highly compatible with mass production standards.
