Ni@Pd core-shell nanoparticles with a mean particle size of 8–9 nm were prepared by solvothermal reduction of bivalent nickel and palladium in oleylamine and trioctylphosphine.Subsequently,the first-ever deposition o...Ni@Pd core-shell nanoparticles with a mean particle size of 8–9 nm were prepared by solvothermal reduction of bivalent nickel and palladium in oleylamine and trioctylphosphine.Subsequently,the first-ever deposition of Ni@Pd core-shell nanoparticles having different compositions on a metal-organic framework(MIL-101)was accomplished by wet impregnation in n-hexane.The Ni@Pd/MIL-101 materials were characterized by powder X-ray diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,and energy-dispersive X-ray spectroscopy and also investigated as catalysts for the hydrogenation of nitrobenzene under mild reaction conditions.At 30 °C and 0.1 MPa of H2 pressure,the Ni@Pd/MIL-101 gives a TOF as high as 375 h–1 for the hydrogenation of nitrobenzene and is applicable to a wide range of substituted nitroarenes.The exceptional performance of this catalyst is believed to result from the significant Ni-Pd interaction in the core-shell structure,together with promotion of the conversions of aromatics by uncoordinated Lewis acidic Cr sites on the MIL-101 support.展开更多
Ni nanoparticles embedded in nitrogen-doped carbon(Ni@C-N) materials were prepared by ther-molysis of a Ni-containing metal-organic framework (Ni-MOF) under inert atmosphere. The as-synthesized Ni@C-N materials we...Ni nanoparticles embedded in nitrogen-doped carbon(Ni@C-N) materials were prepared by ther-molysis of a Ni-containing metal-organic framework (Ni-MOF) under inert atmosphere. The as-synthesized Ni@C-N materials were characterized by powder X-ray diffraction, N_2 adsorp-tion-desorption analysis, scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, and X-ray photoelectron spectroscopy. The MOF-derived Ni-based mate-rials were then examined as heterogeneous catalysts for the oxidation of alkanes under mild reac-tion conditions. The Ni@C-N composites displayed high activity and selectivity toward the oxidation of a variety of saturated C–H bonds, affording the corresponding oxidation products in good-to-excellent yields. Furthermore, the catalysts could be recycled and reused for at least four times without any significant loss in activity and selectivity under the investigated conditions.展开更多
The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to ...The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to efficient charge transfer,the abundance of catalytic sites,and extended light absorption.Herein,an S‐scheme heterojunction of 2D/2D zinc porphyrin‐based metal‐organic frameworks/BiVO_(4)nanosheets(Zn‐MOF/BVON)was fabricated for efficient photocatalytic CO_(2)conversion.The optimal one shows a 22‐fold photoactivity enhancement when compared to the previously reported BiVO4 nanoflake(ca.15 nm),and even exhibits~2‐time improvement than the traditional g‐C3N4/BiVO4 heterojunction.The excellent photoactivities are ascribed to the strengthened S‐scheme charge transfer and separation,promoted CO_(2)activation by the well‐dispersed metal nodes Zn_(2)(COO)_(4)in the Zn‐MOF,and extended visible light response range based on the results of the electrochemical reduction,electron paramagnetic resonance,and in‐situ diffuse reflectance infrared Fourier transform spectroscopy.The dimension‐matched Zn‐MOF/BVON S‐scheme heterojunction endowed with highly efficient charge separation and abundant catalytic active sites contributed to the superior CO2 conversion.This study offers a facile strategy for constructing S‐scheme heterojunctions involving porphyrin‐based MOFs for solar fuel production.展开更多
Visible-light-initiated organic transformations have received much attention because of low cost, relative safety, and environmental friendliness. In this work, we report on a novel type of visible-light-driven photoc...Visible-light-initiated organic transformations have received much attention because of low cost, relative safety, and environmental friendliness. In this work, we report on a novel type of visible-light-driven photocatalysts, namely, porous nanocomposites of CdS-nanoparticle-decorated metal-organic frameworks (MOF), prepared by a simple solvothermal method in which porous MIL-100(Fe) served as the support and cadmium acetate (Cd(Ac)2) as the CdS precursor. When the selective oxidation of benzyl alcohol to benzaldehyde is used as the probe reaction, the results show that the combination of MIL-100(Fe) and CdS semiconductor can remarkably enhance the photocatalytic efficiency at room temperature, as compared to that of pure CdS. The enhanced photocatalytic performance can be attributed to the combined effects of enhanced light absorption, more efficient separation of photogenerated electron-hole pairs, and increased surface area of CdS due to the presence of MIL-100(Fe). This work demonstrates that MOF-based composite materials hold great promise for applications in the field of solar-energy conversion into chemical energy.展开更多
基金supported by the National Natural Science Foundation of China(21322606 and 21436005)the Specialized Research Fund for the Doctoral Program of Higher Education(20120172110012)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Natural Science Foundation of Guangdong Province(S2011020002397 and 2013B090500027)~~
文摘Ni@Pd core-shell nanoparticles with a mean particle size of 8–9 nm were prepared by solvothermal reduction of bivalent nickel and palladium in oleylamine and trioctylphosphine.Subsequently,the first-ever deposition of Ni@Pd core-shell nanoparticles having different compositions on a metal-organic framework(MIL-101)was accomplished by wet impregnation in n-hexane.The Ni@Pd/MIL-101 materials were characterized by powder X-ray diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,and energy-dispersive X-ray spectroscopy and also investigated as catalysts for the hydrogenation of nitrobenzene under mild reaction conditions.At 30 °C and 0.1 MPa of H2 pressure,the Ni@Pd/MIL-101 gives a TOF as high as 375 h–1 for the hydrogenation of nitrobenzene and is applicable to a wide range of substituted nitroarenes.The exceptional performance of this catalyst is believed to result from the significant Ni-Pd interaction in the core-shell structure,together with promotion of the conversions of aromatics by uncoordinated Lewis acidic Cr sites on the MIL-101 support.
基金supported by the National Natural Science Foundation of China (21322606,21436005,21576095)the State Key Laboratory of Pulp and Paper Engineering (2015TS03)+2 种基金the Doctoral Fund of Ministry of Education of China (20120172110012)Fundamental Research Funds for the Central Universities (2015ZP002,2015PT004)Guangdong Natural Science Foundation (2013B090500027)
文摘Ni nanoparticles embedded in nitrogen-doped carbon(Ni@C-N) materials were prepared by ther-molysis of a Ni-containing metal-organic framework (Ni-MOF) under inert atmosphere. The as-synthesized Ni@C-N materials were characterized by powder X-ray diffraction, N_2 adsorp-tion-desorption analysis, scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, and X-ray photoelectron spectroscopy. The MOF-derived Ni-based mate-rials were then examined as heterogeneous catalysts for the oxidation of alkanes under mild reac-tion conditions. The Ni@C-N composites displayed high activity and selectivity toward the oxidation of a variety of saturated C–H bonds, affording the corresponding oxidation products in good-to-excellent yields. Furthermore, the catalysts could be recycled and reused for at least four times without any significant loss in activity and selectivity under the investigated conditions.
文摘The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to efficient charge transfer,the abundance of catalytic sites,and extended light absorption.Herein,an S‐scheme heterojunction of 2D/2D zinc porphyrin‐based metal‐organic frameworks/BiVO_(4)nanosheets(Zn‐MOF/BVON)was fabricated for efficient photocatalytic CO_(2)conversion.The optimal one shows a 22‐fold photoactivity enhancement when compared to the previously reported BiVO4 nanoflake(ca.15 nm),and even exhibits~2‐time improvement than the traditional g‐C3N4/BiVO4 heterojunction.The excellent photoactivities are ascribed to the strengthened S‐scheme charge transfer and separation,promoted CO_(2)activation by the well‐dispersed metal nodes Zn_(2)(COO)_(4)in the Zn‐MOF,and extended visible light response range based on the results of the electrochemical reduction,electron paramagnetic resonance,and in‐situ diffuse reflectance infrared Fourier transform spectroscopy.The dimension‐matched Zn‐MOF/BVON S‐scheme heterojunction endowed with highly efficient charge separation and abundant catalytic active sites contributed to the superior CO2 conversion.This study offers a facile strategy for constructing S‐scheme heterojunctions involving porphyrin‐based MOFs for solar fuel production.
基金This work is supported by the National Natural Science Foundation of China (Grant No. U1232102), National Basic Research Program of China (Nos. 2010CB923302 and 2013CB834605), and the Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) of Ministry of Education (Grant No. 20113402110029).
文摘Visible-light-initiated organic transformations have received much attention because of low cost, relative safety, and environmental friendliness. In this work, we report on a novel type of visible-light-driven photocatalysts, namely, porous nanocomposites of CdS-nanoparticle-decorated metal-organic frameworks (MOF), prepared by a simple solvothermal method in which porous MIL-100(Fe) served as the support and cadmium acetate (Cd(Ac)2) as the CdS precursor. When the selective oxidation of benzyl alcohol to benzaldehyde is used as the probe reaction, the results show that the combination of MIL-100(Fe) and CdS semiconductor can remarkably enhance the photocatalytic efficiency at room temperature, as compared to that of pure CdS. The enhanced photocatalytic performance can be attributed to the combined effects of enhanced light absorption, more efficient separation of photogenerated electron-hole pairs, and increased surface area of CdS due to the presence of MIL-100(Fe). This work demonstrates that MOF-based composite materials hold great promise for applications in the field of solar-energy conversion into chemical energy.