A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto mul...A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto multi-walled carbon nanotubes （MWNTs） film. The morphology of the MWNTs/nano-ZnO electrode has been investigated by scanning electron microscopy （SEM）, and the electrochemical performance of the electrode has also been studied by amperometric method. The resulting electrode offered an excellent detection for hydrogen peroxide at -0.11 V with a linear response range of 9.9×10^-7 to 2.9×10^-3 mol/L with a correlation coefficient of 0.991, and response time 〈5 s. The biosensor displays rapid response and expanded linear response range, and excellent stability.展开更多
Vertical MoS2nanosheets were controllably patterned onto graphene as nanoflowers through a two-step hydrothermal method. The interconnected network and intimate contact between MoS2nanosheets and graphene by vertical ...Vertical MoS2nanosheets were controllably patterned onto graphene as nanoflowers through a two-step hydrothermal method. The interconnected network and intimate contact between MoS2nanosheets and graphene by vertical channels enabled a high mechanical integrity of electrode and cycling stability. In particular, MoS2/graphene nanoflowers anode delivered an ultrahigh specific capacity of 901.8 mA·h/g after 700 stable cycles at 1000 mA/g and a corresponding capacity retention as 98.9% from the second cycle onwards.展开更多
Bi-functional electrocatalysts for acid overall water splitting reactions are crucial but still challenging to the development of proton exchange membrane water electrolysis.Herein,an efficient bi-functional catalyst ...Bi-functional electrocatalysts for acid overall water splitting reactions are crucial but still challenging to the development of proton exchange membrane water electrolysis.Herein,an efficient bi-functional catalyst of Ir/MoS_(2) nanoflowers(Ir/MoS_(2) NFs) catalyst was reported for acidic water electrolysis which can be constructed by coupling three-dimensionally interconnected MoS_(2) NFs with ultrafine Ir nanoparticles.A more suitable adsorption ability for the H* and *OOH intermediates was revealed,where the Ir sites were proposed as the main active center and MoS_(2) promoted the charge relocation to electronically modify the interfacial structure.The significant interfacial charge redistribution between the MoS_(2) NFs and the Ir active sites synergistically induced excellent catalytic activity and stability for the water electrolysis reaction.Specifically,the catalyst required overpotentials of 270 and 35 mV to reach a kinetic current density of 10 mA cm^(-2)for OER and HER,respectively,loading on the glass carbon electrode,with high catalytic kinetics,stability,and catalytic efficiency.A two-electrode system constructed by Ir/MoS_(2) NFs drove 10 mA cm^(-2)at a cell voltage of 1.55 V,about 70 mV lower than that of the commercial Pt/C||IrO_(2) system.In addition,partial surface oxidation of Ir nanoparticles to generate high-valent Ir species was also found significant to accelerate OER.The enhanced catalytic performance was attributed to the strong metal-support interaction in the Ir/MoS_(2) NFs catalyst system that changed the electronic structure of Ir metal and promoted the synergistic catalytic effect between Ir and MoS_(2) NFs.The work presented a novel platform of Ir-catalyst for proton exchange membrane water electrolysis.展开更多
Flower like rutile TiO_2 films were decorated with green-photoluminescent graphene quantum dots（GQDs） and photovoltaic properties were investigated for water splitting application. Rutile TiO_2 nanoflowers（NFs） an...Flower like rutile TiO_2 films were decorated with green-photoluminescent graphene quantum dots（GQDs） and photovoltaic properties were investigated for water splitting application. Rutile TiO_2 nanoflowers（NFs） and GQDs（average width of^12 nm） synthesized separately using a hydrothermal method and TiO_2 NFs were decorated with various amounts of GQDs solution（x = 5, 10, 15 and 20 μL） by spin coating. Optical characterization reveals that GQDs are highly luminescent and absorb UV and visible light photons with wavelengths up to 700 nm. GQDs-x/TiO_2 electrode shows a photocurrent enhancement of ~95% compared to pristine TiO_2 NFs for the optimum sample（x = 15 μL） at an applied potential of P = 0 V using 1 M Na_2SO_4 solution as electrolyte.展开更多
Two-dimensional(2D)MoS_(2) nanomaterials have been extensively studied due to their special structure and high theoretical capacity,but it is still a huge challenge to improve its cycle stability and achieve superior ...Two-dimensional(2D)MoS_(2) nanomaterials have been extensively studied due to their special structure and high theoretical capacity,but it is still a huge challenge to improve its cycle stability and achieve superior fast charge and discharge performance.Herein,a facile one-step hydrothermal method is proposed to synthetize an ordered and self-assembled MoS_(2) nanoflower(MoS_(2)/C NF)with expanded interlayer spacing via embedding a carbon layer into the interlayer.The carbon layer in the MoS_(2) interlayer can speed the transfer of electrons,while the nanoflower structure promotes the ions transport and improves the structural stability during the charging/discharging process.Therefore,MoS_(2)/C NF electrode exhibits exceptional rate performance(318.2 and 302.3 mA·h·g^(-1) at 5.0 and 10.0 A·g^(-1),respectively)and extraordinary cycle durability(98.8%retention after 300 cycles at a current density of 1.0 A·g^(-1)).This work provides a simple and feasible method for constructing high-performance anode composites for sodium ion batteries with excellent cycle durability and fast charge/discharge ability.展开更多
Traditional photo-electcatalyst structures of small noble metal nanoparticles assembling into large-scale photoactive semiconductors still suffer from agglomeration of noble metal nanoparticles,insufficient charge tra...Traditional photo-electcatalyst structures of small noble metal nanoparticles assembling into large-scale photoactive semiconductors still suffer from agglomeration of noble metal nanoparticles,insufficient charge transfer,undesirable photoresponse ability that restricted the photo-electrocatalytic performance.To this end,a novel design strategy is proposed in this work,namely integrating small-scale photoactive materials(doped graphene quantum dots,S,N-GQDs)with large-sized noble metal(Pd P)nanoflowers to form novel photo-electrocatalysts for high-efficient alcohol oxidation reaction.As expected,superior electrocatalytic performance of Pd P/S,N-GQDs for ethylene glycol oxidation is acquired,thanks to the nanoflower structure with larger specific surface area and abundant active sites.Furthermore,nonmetal P are demonstrated,especially optimizing the adsorption strength,enhancing the interfacial contact,reducing metal agglomeration,ensuring uniform and efficient doping of S,N-GQDs,and ultimately significantly boost the catalytic activity of photo-electrocatalysts.展开更多
电化学硝酸根还原制氨(Nitrate reduction to ammonia, NRA)是以硝酸根和水分别作为氮和氢的来源,采用电化学的途径实现室温下氨的绿色合成兼去除水中硝酸盐污染物,对缓解能源危机和环境问题具有重要的研究意义。然而,硝酸根到氨是一个...电化学硝酸根还原制氨(Nitrate reduction to ammonia, NRA)是以硝酸根和水分别作为氮和氢的来源,采用电化学的途径实现室温下氨的绿色合成兼去除水中硝酸盐污染物,对缓解能源危机和环境问题具有重要的研究意义。然而,硝酸根到氨是一个复杂的8e-转移过程且伴随着激烈的析氢副反应,这严重制约了合成氨的选择性和法拉第效率。为此,采用水热合成法及后续的热处理设计制备了泡沫镍负载氧化铜纳米花催化剂并探究其电化学硝酸根还原制氨性能。通过调控硝酸铜与尿素比例、热解温度等合成条件,达到泡沫镍(Ni foam, NF)均匀负载CuO纳米花的目的。结果表明,当Cu(NO3)2、CO(NH2)2的物质的量比为1∶6时,所得到的目标催化剂(CuO-6@NF)在法拉第效率、NH3产率、选择性和硝酸盐转换率方面表现出最佳性能。在-0.23 V vs.RHE情况下,CuO-6@NF NH3的产率达到1.15 mmol·h-1·cm-2,选择性为89.36%,总氮的去除率高达96.71%。此外,该催化剂还表现出良好的再现性、高稳定性以及较宽泛浓度下的适用性。展开更多
以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构...以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构成,在可见光区域有很强的吸收.复合材料中Cu的含量可以通过反应时间进行调控.对染料Procion Red MX-5B(PR)的可见光催化降解,Cu能明显提高Cu2O的光催化性能.当Cu质量分数为27%-71%时,复合材料Cu2O/Cu的催化活性明显高于单相Cu2O.与立方体形貌的Cu2O/Cu复合材料相比,花状纳米Cu2O/Cu复合材料对染料PR有更高的催化降解性能.且该复合材料有较高的循环回收利用率.展开更多
文摘A new amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase at the glassy carbon electrode modified with zinc oxide nanoflowers produced by electrodeposition onto multi-walled carbon nanotubes （MWNTs） film. The morphology of the MWNTs/nano-ZnO electrode has been investigated by scanning electron microscopy （SEM）, and the electrochemical performance of the electrode has also been studied by amperometric method. The resulting electrode offered an excellent detection for hydrogen peroxide at -0.11 V with a linear response range of 9.9×10^-7 to 2.9×10^-3 mol/L with a correlation coefficient of 0.991, and response time 〈5 s. The biosensor displays rapid response and expanded linear response range, and excellent stability.
基金The financial support of the Natural Science Foundation of Changsha,China(No.kq2202094)National Key R&D Program of China(No.2021YFB3701400)。
文摘Vertical MoS2nanosheets were controllably patterned onto graphene as nanoflowers through a two-step hydrothermal method. The interconnected network and intimate contact between MoS2nanosheets and graphene by vertical channels enabled a high mechanical integrity of electrode and cycling stability. In particular, MoS2/graphene nanoflowers anode delivered an ultrahigh specific capacity of 901.8 mA·h/g after 700 stable cycles at 1000 mA/g and a corresponding capacity retention as 98.9% from the second cycle onwards.
基金supported by the National Natural Science Foundation of China (21972124, 22272148)the Priority Academic Program Development of Jiangsu Higher Education Institution。
文摘Bi-functional electrocatalysts for acid overall water splitting reactions are crucial but still challenging to the development of proton exchange membrane water electrolysis.Herein,an efficient bi-functional catalyst of Ir/MoS_(2) nanoflowers(Ir/MoS_(2) NFs) catalyst was reported for acidic water electrolysis which can be constructed by coupling three-dimensionally interconnected MoS_(2) NFs with ultrafine Ir nanoparticles.A more suitable adsorption ability for the H* and *OOH intermediates was revealed,where the Ir sites were proposed as the main active center and MoS_(2) promoted the charge relocation to electronically modify the interfacial structure.The significant interfacial charge redistribution between the MoS_(2) NFs and the Ir active sites synergistically induced excellent catalytic activity and stability for the water electrolysis reaction.Specifically,the catalyst required overpotentials of 270 and 35 mV to reach a kinetic current density of 10 mA cm^(-2)for OER and HER,respectively,loading on the glass carbon electrode,with high catalytic kinetics,stability,and catalytic efficiency.A two-electrode system constructed by Ir/MoS_(2) NFs drove 10 mA cm^(-2)at a cell voltage of 1.55 V,about 70 mV lower than that of the commercial Pt/C||IrO_(2) system.In addition,partial surface oxidation of Ir nanoparticles to generate high-valent Ir species was also found significant to accelerate OER.The enhanced catalytic performance was attributed to the strong metal-support interaction in the Ir/MoS_(2) NFs catalyst system that changed the electronic structure of Ir metal and promoted the synergistic catalytic effect between Ir and MoS_(2) NFs.The work presented a novel platform of Ir-catalyst for proton exchange membrane water electrolysis.
基金Research Council of the Tarbiat Modares University for financial supports
文摘Flower like rutile TiO_2 films were decorated with green-photoluminescent graphene quantum dots（GQDs） and photovoltaic properties were investigated for water splitting application. Rutile TiO_2 nanoflowers（NFs） and GQDs（average width of^12 nm） synthesized separately using a hydrothermal method and TiO_2 NFs were decorated with various amounts of GQDs solution（x = 5, 10, 15 and 20 μL） by spin coating. Optical characterization reveals that GQDs are highly luminescent and absorb UV and visible light photons with wavelengths up to 700 nm. GQDs-x/TiO_2 electrode shows a photocurrent enhancement of ~95% compared to pristine TiO_2 NFs for the optimum sample（x = 15 μL） at an applied potential of P = 0 V using 1 M Na_2SO_4 solution as electrolyte.
基金National Natural Science Foundation of China(51874142)Pearl River S&T Nova Program of Guangzhou(201806010031)+3 种基金the Fundamental Research Funds for the Central Universities(2019JQ09)Guangdong Innovative and Entrepreneurial Research Team Program(2016ZT06N569)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2019TQ05L903)Young Elite Scientists Sponsorship Program by CAST(2019QNRC001).
文摘Two-dimensional(2D)MoS_(2) nanomaterials have been extensively studied due to their special structure and high theoretical capacity,but it is still a huge challenge to improve its cycle stability and achieve superior fast charge and discharge performance.Herein,a facile one-step hydrothermal method is proposed to synthetize an ordered and self-assembled MoS_(2) nanoflower(MoS_(2)/C NF)with expanded interlayer spacing via embedding a carbon layer into the interlayer.The carbon layer in the MoS_(2) interlayer can speed the transfer of electrons,while the nanoflower structure promotes the ions transport and improves the structural stability during the charging/discharging process.Therefore,MoS_(2)/C NF electrode exhibits exceptional rate performance(318.2 and 302.3 mA·h·g^(-1) at 5.0 and 10.0 A·g^(-1),respectively)and extraordinary cycle durability(98.8%retention after 300 cycles at a current density of 1.0 A·g^(-1)).This work provides a simple and feasible method for constructing high-performance anode composites for sodium ion batteries with excellent cycle durability and fast charge/discharge ability.
基金supported by Zhejiang Provincial Natural Science Foundation of China(No.LTGS23B030002)the National Natural Science Foundation of China(Nos.21978111 and 22278175)。
文摘Traditional photo-electcatalyst structures of small noble metal nanoparticles assembling into large-scale photoactive semiconductors still suffer from agglomeration of noble metal nanoparticles,insufficient charge transfer,undesirable photoresponse ability that restricted the photo-electrocatalytic performance.To this end,a novel design strategy is proposed in this work,namely integrating small-scale photoactive materials(doped graphene quantum dots,S,N-GQDs)with large-sized noble metal(Pd P)nanoflowers to form novel photo-electrocatalysts for high-efficient alcohol oxidation reaction.As expected,superior electrocatalytic performance of Pd P/S,N-GQDs for ethylene glycol oxidation is acquired,thanks to the nanoflower structure with larger specific surface area and abundant active sites.Furthermore,nonmetal P are demonstrated,especially optimizing the adsorption strength,enhancing the interfacial contact,reducing metal agglomeration,ensuring uniform and efficient doping of S,N-GQDs,and ultimately significantly boost the catalytic activity of photo-electrocatalysts.
文摘以硝酸铜为前驱体,不采用任何模板,通过逐步水热法合成了花状Cu2O/Cu复合纳米材料.用扫描电镜(SEM)、X射线衍射(XRD)和紫外-可见漫反射光谱(DRS)对样品进行表征.结果表明,花状纳米Cu2O/Cu材料是由长为300-500nm,宽为30-70nm的带状花瓣构成,在可见光区域有很强的吸收.复合材料中Cu的含量可以通过反应时间进行调控.对染料Procion Red MX-5B(PR)的可见光催化降解,Cu能明显提高Cu2O的光催化性能.当Cu质量分数为27%-71%时,复合材料Cu2O/Cu的催化活性明显高于单相Cu2O.与立方体形貌的Cu2O/Cu复合材料相比,花状纳米Cu2O/Cu复合材料对染料PR有更高的催化降解性能.且该复合材料有较高的循环回收利用率.
基金supported by the National Natural Science Foundation of China(21575131)the Key Scientific Research Project of High Schools in Henan Province(16A430025,17A480009)~~
