A series of highly active Ni2P-Mo S2/γ-Al2O3 catalysts were prepared and characterized, the catalytic performance of which was evaluated through hydrodesulfurization of dibenzothiophene. The result indicated that whe...A series of highly active Ni2P-Mo S2/γ-Al2O3 catalysts were prepared and characterized, the catalytic performance of which was evaluated through hydrodesulfurization of dibenzothiophene. The result indicated that when the amount of Ni2 P was 4%, the catalyst showed a relatively high activity to provide a reliable reference for the hydrodesulfurization pathway in comparison with the conventional Ni Mo and Ni Mo P catalysts. The physicochemical properties of the catalysts were correlated with their catalytic activity and selectivity on hydrodesulfurization. The stacking number of active Mo S2 phases was important for influencing the hydrogenation activity.展开更多
Oil-soluble MoS2 nanoparticles with narrow size distribution have been synthesized by a facile composite-surfactants-aided-solvothermal process.The as-prepared nanoparticles can be directly used as hydrogenation nanoc...Oil-soluble MoS2 nanoparticles with narrow size distribution have been synthesized by a facile composite-surfactants-aided-solvothermal process.The as-prepared nanoparticles can be directly used as hydrogenation nanocatalysts or as precursors to achieve efficient supported nanocatalysts.The surfaces of these nanoparticles are proposed to be encapsulated within a layer of organic modifiers,which are responsible for the enhancement of their solubility in organic solvents.The activated-carbon supported MoS2 nanocatalysts exhibit higher activity than the unsupported ones towards hydrogenation reactions of naphthalene,owing to the synergistic effects between nanoparticles and supports.The advantages of the present nanocatalysts,such as removal of conventional presulfiding requirements and reduction of nanoparticle aggregations,make them become promising applications in related petroleum chemical industry.展开更多
Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐di...Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐dimensional(2D)g‐C3N4nanoplates and zero‐dimensional(0D)MoS2quantum dots(QDs)was prepared through the combination of a hydrothermal process and microemulsion preparation.The morphologies,structures,and optical properties of the as‐prepared photocatalysts were characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,atomic force microscopy,transmission electron microscopy,and UV‐vis diffuse reflectance spectroscopy.In addition,the photocatalytic performances of the prepared2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible‐light irradiation.The results demonstrated that the introduction of MoS2QDs to g‐C3N4greatly enhanced the photocatalytic efficiency.For the optimum7%MoS2QD/g‐C3N4photocatalyst,the degradation rate constant was8.8times greater than that of pure g‐C3N4under visible‐light irradiation.Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2QD/g‐C3N4composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g‐C3N4or MoS2QDs.Active species trapping,terephthalic acid photoluminescence,and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species,including hydroxyl radicals and superoxide radicals.The possible enhanced photocatalytic mechanism was attributed to a direct Z‐scheme system,which not only can increase the separation efficiency of photogenerated electron‐hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances.This work provides an effective synthesis approach and insight to help develop other C3N4‐based direct Z‐scheme photocatalytic systems for environmental purification and energy conversion.展开更多
Single‐atom catalysts(SACs)have demonstrated excellent performances in chemoselective hydrogenation reactions.However,the employment of precious metals and/or organic solvents compromises their sustainability.Herein,...Single‐atom catalysts(SACs)have demonstrated excellent performances in chemoselective hydrogenation reactions.However,the employment of precious metals and/or organic solvents compromises their sustainability.Herein,we for the first time report the chemoselective hydrogenation of 3‐nitrostyrene over noble‐metal‐free Co‐N‐C SAC in green solvent—compressed CO2.An interesting inverted V‐curve relation is observed between the catalytic activity and CO2 pressure,where the conversion of 3‐nitrostyrene reaches the maximum of 100%at 5.0 MPa CO2(total pressure of 8.1 MPa).Meanwhile,the selectivities to 3‐vinylaniline at all pressures remain high(>99%).Phase behavior studies reveal that,in sharp contrast with the single phase which is formed at total pressure above 10.8 MPa,bi‐phase composed of CO2/H_(2)gas‐rich phase and CO2‐expanded substrate liquid phase forms at total pressure of 8.1 MPa,which dramatically changes the reaction kinetics of the catalytic system.The reaction order with respect to H_(2)pressure decreases from~0.5 to zero at total pressure of 8.1 MPa,suggesting the dissolved CO2 in 3‐nitrostyrene greatly promotes the dissolution of H_(2)in the substrate,which is responsible for the high catalytic activity at the peak of the inverted V‐curve.展开更多
以钼酸钠(Na_2MoO_4·2H_2O)、硫脲(NH_2CSNH_2)、CTAB为原料,利用水热法合成了MoS_2/C球状纳米花复合材料。通过XRD、SEM、TEM、TG等分析测试方法,研究了不同CTAB添加量对MoS_2/C复合材料的微观结构、表面形貌的影响规律,结果显示...以钼酸钠(Na_2MoO_4·2H_2O)、硫脲(NH_2CSNH_2)、CTAB为原料,利用水热法合成了MoS_2/C球状纳米花复合材料。通过XRD、SEM、TEM、TG等分析测试方法,研究了不同CTAB添加量对MoS_2/C复合材料的微观结构、表面形貌的影响规律,结果显示,有部分无定形碳嵌入了MoS_2层间,并抑制了MoS_2(002)面的堆积。电化学测试表明:与纯MoS_2相比,MoS_2/C复合材料具有更好的电化学性能,当加入0.025 g CTAB时首次放电比容量达到730 m Ah/g,在100 m A/g的电流密度下经过100次循环比容量稳定在415 m Ah/g。在此基础上讨论了MoS_2/C球状纳米花复合材料的可能生长机理以及对材料电化学性能的影响规律。展开更多
基金financially supported by the Natural Science Foundation of Anhui Province(No.1408085QB44)the Natural Science Foundation of Educational Committee of Anhui Province(No.KJ2013B243)the Youth Foundation of Huaibei Normal University(2013xqz01)
文摘A series of highly active Ni2P-Mo S2/γ-Al2O3 catalysts were prepared and characterized, the catalytic performance of which was evaluated through hydrodesulfurization of dibenzothiophene. The result indicated that when the amount of Ni2 P was 4%, the catalyst showed a relatively high activity to provide a reliable reference for the hydrodesulfurization pathway in comparison with the conventional Ni Mo and Ni Mo P catalysts. The physicochemical properties of the catalysts were correlated with their catalytic activity and selectivity on hydrodesulfurization. The stacking number of active Mo S2 phases was important for influencing the hydrogenation activity.
基金supported by the Shandong Provincial Natural Science Foundation(ZR2009BQ008)the Fundamental Research Funds for the Central Universities(10CX03008A)
文摘Oil-soluble MoS2 nanoparticles with narrow size distribution have been synthesized by a facile composite-surfactants-aided-solvothermal process.The as-prepared nanoparticles can be directly used as hydrogenation nanocatalysts or as precursors to achieve efficient supported nanocatalysts.The surfaces of these nanoparticles are proposed to be encapsulated within a layer of organic modifiers,which are responsible for the enhancement of their solubility in organic solvents.The activated-carbon supported MoS2 nanocatalysts exhibit higher activity than the unsupported ones towards hydrogenation reactions of naphthalene,owing to the synergistic effects between nanoparticles and supports.The advantages of the present nanocatalysts,such as removal of conventional presulfiding requirements and reduction of nanoparticle aggregations,make them become promising applications in related petroleum chemical industry.
基金supported by National Natural Science Foundation of China(51672113)Six Talent Peaks Project in Jiangsu Province(2015-XCL-026)+3 种基金Natural Science Foundation of Jiangsu Province(BK20171299)State Key Laboratory of Photocatalysis on Energy and Environment(SKLPEE-KF201705),Fuzhou UniversityState Key Laboratory of Advanced Technology for Materials Synthesis and Processing(2016-KF-10),Wuhan University of Technologythe Qing Lan Project Foundation of Jiangsu Province~~
文摘Graphite‐like carbon nitride(g‐C3N4)‐based compounds have attracted considerable attention because of their excellent photocatalytic performance.In this work,a novel direct Z‐scheme system constructed from two‐dimensional(2D)g‐C3N4nanoplates and zero‐dimensional(0D)MoS2quantum dots(QDs)was prepared through the combination of a hydrothermal process and microemulsion preparation.The morphologies,structures,and optical properties of the as‐prepared photocatalysts were characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,atomic force microscopy,transmission electron microscopy,and UV‐vis diffuse reflectance spectroscopy.In addition,the photocatalytic performances of the prepared2D/0D hybrid composites were evaluated based on the photodegradation of rhodamine B under visible‐light irradiation.The results demonstrated that the introduction of MoS2QDs to g‐C3N4greatly enhanced the photocatalytic efficiency.For the optimum7%MoS2QD/g‐C3N4photocatalyst,the degradation rate constant was8.8times greater than that of pure g‐C3N4under visible‐light irradiation.Photocurrent and electrochemical impedance spectroscopy results further demonstrated that the MoS2QD/g‐C3N4composites exhibited higher photocurrent density and lower chargetransfer resistance than those of the pure g‐C3N4or MoS2QDs.Active species trapping,terephthalic acid photoluminescence,and nitro blue tetrazolium transformation experiments were performed to investigate the evolution of reactive oxygen species,including hydroxyl radicals and superoxide radicals.The possible enhanced photocatalytic mechanism was attributed to a direct Z‐scheme system,which not only can increase the separation efficiency of photogenerated electron‐hole pairs but also possesses excellent oxidation and reduction ability for high photocatalytic performances.This work provides an effective synthesis approach and insight to help develop other C3N4‐based direct Z‐scheme photocatalytic systems for environmental purification and energy conversion.
文摘Single‐atom catalysts(SACs)have demonstrated excellent performances in chemoselective hydrogenation reactions.However,the employment of precious metals and/or organic solvents compromises their sustainability.Herein,we for the first time report the chemoselective hydrogenation of 3‐nitrostyrene over noble‐metal‐free Co‐N‐C SAC in green solvent—compressed CO2.An interesting inverted V‐curve relation is observed between the catalytic activity and CO2 pressure,where the conversion of 3‐nitrostyrene reaches the maximum of 100%at 5.0 MPa CO2(total pressure of 8.1 MPa).Meanwhile,the selectivities to 3‐vinylaniline at all pressures remain high(>99%).Phase behavior studies reveal that,in sharp contrast with the single phase which is formed at total pressure above 10.8 MPa,bi‐phase composed of CO2/H_(2)gas‐rich phase and CO2‐expanded substrate liquid phase forms at total pressure of 8.1 MPa,which dramatically changes the reaction kinetics of the catalytic system.The reaction order with respect to H_(2)pressure decreases from~0.5 to zero at total pressure of 8.1 MPa,suggesting the dissolved CO2 in 3‐nitrostyrene greatly promotes the dissolution of H_(2)in the substrate,which is responsible for the high catalytic activity at the peak of the inverted V‐curve.
文摘以钼酸钠(Na_2MoO_4·2H_2O)、硫脲(NH_2CSNH_2)、CTAB为原料,利用水热法合成了MoS_2/C球状纳米花复合材料。通过XRD、SEM、TEM、TG等分析测试方法,研究了不同CTAB添加量对MoS_2/C复合材料的微观结构、表面形貌的影响规律,结果显示,有部分无定形碳嵌入了MoS_2层间,并抑制了MoS_2(002)面的堆积。电化学测试表明:与纯MoS_2相比,MoS_2/C复合材料具有更好的电化学性能,当加入0.025 g CTAB时首次放电比容量达到730 m Ah/g,在100 m A/g的电流密度下经过100次循环比容量稳定在415 m Ah/g。在此基础上讨论了MoS_2/C球状纳米花复合材料的可能生长机理以及对材料电化学性能的影响规律。
