Interface engineering has been widely investigated to regulate the structure and performance of electrodes and photoelectrodes,but the investigation of multiple carbon interface modifications on the electrocatalytic o...Interface engineering has been widely investigated to regulate the structure and performance of electrodes and photoelectrodes,but the investigation of multiple carbon interface modifications on the electrocatalytic oxygen evolution reaction(OER)is still shortage.Herein,we report remarkable promotion of OER performance on the NiFe‐based nanocomposite electrocatalyst via the synergy of multiple carbon‐based interface engineering.Specifically,carbon nanotubes were in situ grown on carbon fiber paper to improve the interface between CFP and NiFeO_(x)H_(y),and graphite carbon nanoparticles were in situ loaded and partly doped into the NiFeO_(x)H_(y) to modify the intergranular interface charge transfer and electronic structure of NiFeO_(x)H_(y).Consequently,the as‐obtained NiFeO_(x)H_(y)‐C/CNTs/CFP catalyst exhibited significantly enhanced electrocatalytic OER activity with an overpotential of 202 mV at 10 mA cm^(-2) in 1 mol L^(-1) KOH.Our work not only extends application of carbon materials but also provides an alternative strategy to develop highly efficient electrocatalysts.展开更多
A novel gas-phase electrocatalytic cell containing a low-temperature proton exchange membrane(PEM)was developed to electrochemically convert CO_2into organic compounds.Two different Cu-based cathode catalysts(Cu and C...A novel gas-phase electrocatalytic cell containing a low-temperature proton exchange membrane(PEM)was developed to electrochemically convert CO_2into organic compounds.Two different Cu-based cathode catalysts(Cu and Cu–C)were prepared by physical vapor deposition method(sputtering)and subsequently employed for the gas-phase electroreduction of CO_2at different temperatures(70–90°C).The prepared electrodes Cu and Cu–C were characterized by X-ray diffraction(XRD),X-ray photoemission spectroscopy(XPS)and scanning electron microscopy(SEM).As revealed,Cu is partially oxidized on the surface of the samples and the Cu and Cu–C cathodic catalysts were comprised of a porous,continuous,and homogeneous film with nanocrystalline Cu with a grain size of 16 and 8 nm,respectively.The influence of the applied current and temperature on the electro-catalytic activity and selectivity of these materials was investigated.Among the two investigated electrodes,the pure Cu catalyst film showed the highest CO_2specific electrocatalytic reduction rates and higher selectivity to methanol formation compared to the Cu–C electrode,which was attributed to the higher particle size of the former and lower Cu O/Cu ratio.The obtained results show potential interest for the possible use of electrical renewable energy for the transformation of CO_2into valuable products using low metal loading Cu based electrodes(0.5 mg Cu cm^(-2))prepared by sputtering.展开更多
Carbon nanotubes-Nafion (CNTs-Nation) composites were prepared by impregnated CNTs with Nation in ethanol solution and characterized by FT-IR. Pt-Ru catalysts supported on CNTs-Nafion composites were synthesized by ...Carbon nanotubes-Nafion (CNTs-Nation) composites were prepared by impregnated CNTs with Nation in ethanol solution and characterized by FT-IR. Pt-Ru catalysts supported on CNTs-Nafion composites were synthesized by microwave-assisted polyol process. The physical and electrochemical properties of the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), CO stripping voltammetry, cyclic voltammetry (CV) and chronoamperometry (CA). The results showed that the Nation incorporation in CNTs-Nation composites did not significantly alter the oxygen-containing groups on the CNTs surface. The Pt-Ru catalyst supported on CNTs-Nafion composites with 2 wt% Naton showed good dispersion and the best CO oxidation and methanol electro-oxidation activities.展开更多
The effect of irreversibly adsorbed Bi on commercial Pt/C catalyst toward glucose electro-oxidation re- action (GOR) in different electrolytes (acidic, neutral, alkaline) is studied. Bi is successfully deposited o...The effect of irreversibly adsorbed Bi on commercial Pt/C catalyst toward glucose electro-oxidation re- action (GOR) in different electrolytes (acidic, neutral, alkaline) is studied. Bi is successfully deposited on Pt/C from Bi3+ containing acidic solution from 0 to 90% coverage degree. The stability of the Bi layer in acid and alkaline corresponded to previous studies and started to dissolve at 0.7 V and 0.8 V versus re- versible hydrogen electrode (RIIE), respectively. However, in neutral phosphate buffer the layer showed remarkable stability to at least 1.2V versus RHE. Bi modification at low (20%) and high (80%) coverage showed the highest increase in the activity of Pt/C toward GOR by a factor up to 7 due to the increased poisoning resistance of the modified catalyst. The effect of poisoning was especially reduced at high Bi coverage (80%), which shows that adsorbate blocked by Bi through the third-body effect is effective. Finally, with or without Bi modification GOR on PtIC was most active in alkaline conditions.展开更多
Alloying degree, particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent(s) used in the preparation process can affect the particle size and alloying de...Alloying degree, particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent(s) used in the preparation process can affect the particle size and alloying degree of the object substance, which lead to a great positive impact on its properties. In this work, three types of solvents and their mixtures were used in preparation of the Pt-Ru/C catalysts by chemical reduction of metal precursors with sodium borohydride at room temperature. The structure of the catalysts was characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The catalytic activity and stability for methanol electro-oxidation were studied by Cyclic Voltammetry (CV) and Chronoamperometry (CA). Pt-Ru/C catalyst prepared in H2O or binary solvents of H2O and isopropanol had large particle size and low alloying degree leading to low catalytic activity and less stability in methanol electro-oxidation. When tetrahydrofuran was added to the above solvent systems, Pt-Ru/C catalyst prepared had smaller particle size and higher alloying degree which resulted in better catalytic activity, lower onset and peak potentials, compared with the above catalysts. Moreover, the catalyst prepared in ternary solvents of isopropanol, water and tetrahydrofuran had the smallest particle size, and the high alloying degree and the dispersion kept unchanged. Therefore, this kind of catalyst showed the highest catalytic activity and good stability for methanol electro-oxidation.展开更多
Pd@Ru bimetallic nanoparticles deposited on carbon black electro-catalysts have been fabricated by microwave-assisted polyol reduction method and investigated for methanol electro-oxidation (MEO). The structure and ...Pd@Ru bimetallic nanoparticles deposited on carbon black electro-catalysts have been fabricated by microwave-assisted polyol reduction method and investigated for methanol electro-oxidation (MEO). The structure and electro-catalytic properties of the as-prepared catalysts were characterized by XRD, SEM, TEM and cyclic voltammetry (CV) techniques. The results showed that the introduction of Ru element (2-10 wt%) into Pd 20 wt%/C (hereafter, denoted as Pd/C) produced a series of core-shell structured binary catalysts. Pd@Ru 5 wt%/C (hereafter, denoted as Pd@Rus/C) catalyst displayed the highest catalytic activity towards MEO. And the mass activity of Pd@Ru5/C electrode catalyst at E = -0.038 V (vs. Hg/HgO) was 1.42 times higher than that of Pd/C electrode catalyst. In addition, the relationship between the catalytic stability for MEO on Pd@Ru/C catalysts and the value of dbp/dfp (the ratio of MEO peak current density in the negative scan and positive scan) were also investigated. The result demonstrated that Pd@Rus/C offering the smallest value of Jbp/Jfp displayed the best stable catalytic performance.展开更多
A novel Fe-Pd bifunctional catalyst supported on mesh-type γ-Al<sub>2</sub>O<sub>3</sub>/Al was prepared and applied in the degradation of Rhodamine B (RhB). The monolithic mesh-type Fe-Pd/γ-...A novel Fe-Pd bifunctional catalyst supported on mesh-type γ-Al<sub>2</sub>O<sub>3</sub>/Al was prepared and applied in the degradation of Rhodamine B (RhB). The monolithic mesh-type Fe-Pd/γ-Al<sub>2</sub>O<sub>3</sub>/Al bifunctional catalyst could be separated from the solution directly and could synthesize H<sub>2</sub>O<sub>2</sub> in situ. The characterization results showed that Fe could improve the dispersion of Pd<sup>0</sup>, and the electronic interactions between Pd and Fe could increase the Pd<sup>0</sup> contents on the catalyst, which increased the productivity of H<sub>2</sub>O<sub>2</sub>. Furthermore, DFT calculations proved that the addition of Fe could inhibit the dissociation of O<sub>2</sub> and promote the nondissociative hydrogenation of O<sub>2</sub> on the surface of Fe-Pd/γ-Al<sub>2</sub>O<sub>3</sub>/Al, which resulted in the increasement of H<sub>2</sub>O<sub>2</sub> selectivity. Finally, the in-situ synthesized H<sub>2</sub>O<sub>2</sub> by Pd was furtherly decomposed in situ by Fe to generate<span lang="EN-US" style="white-space:normal;font-size:10pt;font-family:;" "=""><span lang="EN-US" style="white-space:normal;font-size:10pt;font-family:;" "=""><span style="white-space:normal;color:#FFFFFF;font-family:Roboto, " background-color:#d46399;"=""><img src="Edit_e6a13073-7151-40b7-b2c3-a59a59d064fc.png" alt="" /></span></span></span>OH radicals to degrade organic pollutants. Therefore, Fe-Pd/ γ-Al<sub>2</sub>O<sub>3</sub>/Al catalysts exhibited excellent catalytic activity in the in-situ synthesis of H<sub>2</sub>O<sub>2</sub> and the degradation of RhB due to the synergistic effects between Pd and Fe on the catalyst. It provided a new idea for the design of bifunctional electro-Fenton catalysts. Ten cycles of experiments showed that the catalytic activity of Fe-Pd/γ-Al<sub>2</sub>O<sub>3</sub>/Al catalyst could be maintained for a long time.展开更多
We reports an efficient approach for production of hydrogen from crude bio-oil and biomass char in the dual fixed-bed system by using the electrochemical catalytic reforming method. The maximal absolute hydrogen yield...We reports an efficient approach for production of hydrogen from crude bio-oil and biomass char in the dual fixed-bed system by using the electrochemical catalytic reforming method. The maximal absolute hydrogen yield reached 110.9 g H2/kg dry biomass. The product gas was a mixed gas containing 72%H2, 26%CO2, 1.9%CO, and a trace amount of CH4. It was observed that adding biomass char (a by-product of pyrolysis of biomass) could remarkably increase the absolute H2 yield (about 20%-50%). The higher reforming temperature could enhance the steam reforming reaction of organic compounds in crude bio-oil and the reaction of CO and H20. In addition, the CuZn-Al2O3 catalyst in the water-gas shift bed could also increase the absolute H2 yield via shifting CO to CO2.展开更多
One of the thrust areas of research is to find an alternative fuel to meet the increasing demand for energy.Glucose is a good source of alternative fuel for clean energy and is easily available in abundance from both ...One of the thrust areas of research is to find an alternative fuel to meet the increasing demand for energy.Glucose is a good source of alternative fuel for clean energy and is easily available in abundance from both naturally occurring plants and industrial processes.Electrochemical oxidation of glucose in fuel cell requires high electro-catalytic surface of the electrode to produce the clean electrical energy w ith minimum energy losses in the cell.Pt and Pt based alloys exhibit high electro-catalytic properties but they are expensive.For energy synthesis at economically cheap price,non Pt based inexpensive high electro catalytic material is required.Electro synthesized Zn O-Al2O3composite is found to exhibit high electro-catalytic properties for glucose oxidation.The Cyclic Voltammetry and Chronoamperometry curves reflect that the material is very much comparable to Pt as far as the maximum current and the steady state current delivered from the glucose oxidation are concerned.XRD image confirms the mixed oxide composite.SEM images morphology show increased 3D surface areas at higher magnification.This attributed high current delivered from electrochemical oxidation of glucose on this electrode surface.展开更多
Nanocrystalline tungsten carbide thin films were fabricated on graphite substrates by plasma enhanced chemical vapor deposition (PECVD) at H2 and Ar atmosphere, using WF6 and CH4 as precursors. The crystal phase, st...Nanocrystalline tungsten carbide thin films were fabricated on graphite substrates by plasma enhanced chemical vapor deposition (PECVD) at H2 and Ar atmosphere, using WF6 and CH4 as precursors. The crystal phase, structure and chemical components of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectrometer (EDS), respectively. The results show that the film prepared at CH4/WF6 concentration ratio of 20 and at 800℃ is composed of spherical particles with a diameter of 20-35 nm. Electrochemical investigations show that the electrochemical real surface area of electrode of the film is large, and the electrode of the film exhibits higher electro-catalytic activity in the reaction of methanol oxidation. The designated constant current of the film catalyst is 123.6 mA/cm^2 in the mixture solution of H2SO4 and CH3OH at the concentration of 0.5 and 2.0 mol/L at 70℃, and the designated constant potential is only 0.306 V (vs SCE).展开更多
Surface area,pore properties,synergistic behavior,homogenous dispersion,and interactions between carbon matrix and metal-nanostructures are the key factors for achieving the better performance of carbon-metal based(el...Surface area,pore properties,synergistic behavior,homogenous dispersion,and interactions between carbon matrix and metal-nanostructures are the key factors for achieving the better performance of carbon-metal based(electro)catalysts.However,the traditional hydro-or solvothermal preparation of(electro)catalysts,particularly,bi-or tri-metallic nanostructures anchored graphene(G)or carbon nanotubes(CNTs),often pose to poor metal–support interaction,low synergism,and patchy dispersion.At first,bimetallic flower-like-CuFeS_(2)/NG and cube-like-NiFeS_(2)/NCNTs nanocomposites were prepared by solvothermal method.The resultant bimetallic nanocomposites were employed to derive the 2D-nano-sandwiched Fe_(2)CuNiS_(4)/NGCNTs-SW(electro)catalyst by a very simple and green urea-mediated“mix-heat”method.The desired physicochemical properties of Fe_(2)CuNiS_(4)/NGCNTs-SW such as multiple active sites,strong metal-support interaction,homogenous dispersion and enhanced surface area were confirmed by various microscopic and spectroscopic techniques.To the best of our knowledge,this is the first urea-mediated“mix-heat”method for preparing 2D-nano-sandwiched carbon-metal-based(electro)catalysts.The Fe_(2)CuNiS_(4)/NGCNTs-SW was found to be highly effective for alkaline-mediated oxygen evolution reaction at low onset potential of 284.24 mV,and the stable current density of 10 mA cm^(−2) in 1.0 m KOH for 10 h.Further,the Fe_(2)CuNiS_(4)/NGCNTs-SW demonstrated excellent catalytic activity in the reduction of 4-nitrophenol with good kapp value of 87.71×10^(−2)s^(-1)and excellent reusability over five cycles.Overall,the developed urea-mediated“mix-heat”method is highly efficient for the preparation of metal-nanoarchitectures anchored 2D-nano-sandwiched(electro)catalysts with high synergism,uniform dispersion and excellent metal-support interaction.展开更多
Anode electro-catalysts for direct dimethyl-ether fuel cell (DDFC), Pt/C, PtRu/C (1∶1) and PtSn/C (3∶2), were prepared by chemical impregnation-reductio n method with formaldehyde as the reductant. DME electro-oxida...Anode electro-catalysts for direct dimethyl-ether fuel cell (DDFC), Pt/C, PtRu/C (1∶1) and PtSn/C (3∶2), were prepared by chemical impregnation-reductio n method with formaldehyde as the reductant. DME electro-oxidation and adsorptio n at Pt electrode and Pt electro-catalysts were investigated by Cyclic Voltammet ry(CV), Quasi-steady state polarization and Gas Chromatography(GC). CV showed th at there were two current peaks of DME electro-oxidation at Pt electrode around 0.8V (vs RHE); DME was adsorbed at Pt electrode more weakly and slowly than oxyg en, methanol, even hydrogen; the onset potential of DME oxidation was 50mV less than that of methanol, and DME peak potential 110 mV lower, thus more advantageo us for using in fuel cells than methanol. GC showed that small amount of HCHO wa s generated during DME electro-oxidation. The mechanism of DME electro-oxidation was proposed. Among the three electro-catalysts (Pt/C, PtRu/C and PtSn/C), Pt a lloy catalysts, especially PtRu/C, showed a higher performance toward DME electr o-oxidation, as in the case of methanol. Temperature experiments showed that bot h DME electro-oxidation and adsorption on Pt and Pt alloy catalysts were favored with increased temperature.展开更多
文摘Interface engineering has been widely investigated to regulate the structure and performance of electrodes and photoelectrodes,but the investigation of multiple carbon interface modifications on the electrocatalytic oxygen evolution reaction(OER)is still shortage.Herein,we report remarkable promotion of OER performance on the NiFe‐based nanocomposite electrocatalyst via the synergy of multiple carbon‐based interface engineering.Specifically,carbon nanotubes were in situ grown on carbon fiber paper to improve the interface between CFP and NiFeO_(x)H_(y),and graphite carbon nanoparticles were in situ loaded and partly doped into the NiFeO_(x)H_(y) to modify the intergranular interface charge transfer and electronic structure of NiFeO_(x)H_(y).Consequently,the as‐obtained NiFeO_(x)H_(y)‐C/CNTs/CFP catalyst exhibited significantly enhanced electrocatalytic OER activity with an overpotential of 202 mV at 10 mA cm^(-2) in 1 mol L^(-1) KOH.Our work not only extends application of carbon materials but also provides an alternative strategy to develop highly efficient electrocatalysts.
基金Financial support from the "Spanish Ministry of Economy, Industry, and Competitiveness" (Project CTQ2016-75491-R)from Abengoa Researchthe Spanish Ministry of Economy, Industry, and Competitiveness for financial support through the Ramón y Cajal Program, Grant: RYC-2015-19230
文摘A novel gas-phase electrocatalytic cell containing a low-temperature proton exchange membrane(PEM)was developed to electrochemically convert CO_2into organic compounds.Two different Cu-based cathode catalysts(Cu and Cu–C)were prepared by physical vapor deposition method(sputtering)and subsequently employed for the gas-phase electroreduction of CO_2at different temperatures(70–90°C).The prepared electrodes Cu and Cu–C were characterized by X-ray diffraction(XRD),X-ray photoemission spectroscopy(XPS)and scanning electron microscopy(SEM).As revealed,Cu is partially oxidized on the surface of the samples and the Cu and Cu–C cathodic catalysts were comprised of a porous,continuous,and homogeneous film with nanocrystalline Cu with a grain size of 16 and 8 nm,respectively.The influence of the applied current and temperature on the electro-catalytic activity and selectivity of these materials was investigated.Among the two investigated electrodes,the pure Cu catalyst film showed the highest CO_2specific electrocatalytic reduction rates and higher selectivity to methanol formation compared to the Cu–C electrode,which was attributed to the higher particle size of the former and lower Cu O/Cu ratio.The obtained results show potential interest for the possible use of electrical renewable energy for the transformation of CO_2into valuable products using low metal loading Cu based electrodes(0.5 mg Cu cm^(-2))prepared by sputtering.
基金supported by National Natural Science Foundation of China (NO.0576023)Key Project of Science and Technology Department of Guangdong Province (NO.2008B010800036 NO.2008B010800037)
文摘Carbon nanotubes-Nafion (CNTs-Nation) composites were prepared by impregnated CNTs with Nation in ethanol solution and characterized by FT-IR. Pt-Ru catalysts supported on CNTs-Nafion composites were synthesized by microwave-assisted polyol process. The physical and electrochemical properties of the catalysts were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), CO stripping voltammetry, cyclic voltammetry (CV) and chronoamperometry (CA). The results showed that the Nation incorporation in CNTs-Nation composites did not significantly alter the oxygen-containing groups on the CNTs surface. The Pt-Ru catalyst supported on CNTs-Nafion composites with 2 wt% Naton showed good dispersion and the best CO oxidation and methanol electro-oxidation activities.
基金Jane and Aatos Erkko FoundationJenny and Antti Wihuri Foundation for funding
文摘The effect of irreversibly adsorbed Bi on commercial Pt/C catalyst toward glucose electro-oxidation re- action (GOR) in different electrolytes (acidic, neutral, alkaline) is studied. Bi is successfully deposited on Pt/C from Bi3+ containing acidic solution from 0 to 90% coverage degree. The stability of the Bi layer in acid and alkaline corresponded to previous studies and started to dissolve at 0.7 V and 0.8 V versus re- versible hydrogen electrode (RIIE), respectively. However, in neutral phosphate buffer the layer showed remarkable stability to at least 1.2V versus RHE. Bi modification at low (20%) and high (80%) coverage showed the highest increase in the activity of Pt/C toward GOR by a factor up to 7 due to the increased poisoning resistance of the modified catalyst. The effect of poisoning was especially reduced at high Bi coverage (80%), which shows that adsorbate blocked by Bi through the third-body effect is effective. Finally, with or without Bi modification GOR on PtIC was most active in alkaline conditions.
基金supported by 863 Project(No.2006AA05Z102)the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China (No.707050)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education (No.20060610023)Chengdu Natural Science Foundation (Nos.06GGYB449GX-030,and 07GGZD139GX)
文摘Alloying degree, particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent(s) used in the preparation process can affect the particle size and alloying degree of the object substance, which lead to a great positive impact on its properties. In this work, three types of solvents and their mixtures were used in preparation of the Pt-Ru/C catalysts by chemical reduction of metal precursors with sodium borohydride at room temperature. The structure of the catalysts was characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The catalytic activity and stability for methanol electro-oxidation were studied by Cyclic Voltammetry (CV) and Chronoamperometry (CA). Pt-Ru/C catalyst prepared in H2O or binary solvents of H2O and isopropanol had large particle size and low alloying degree leading to low catalytic activity and less stability in methanol electro-oxidation. When tetrahydrofuran was added to the above solvent systems, Pt-Ru/C catalyst prepared had smaller particle size and higher alloying degree which resulted in better catalytic activity, lower onset and peak potentials, compared with the above catalysts. Moreover, the catalyst prepared in ternary solvents of isopropanol, water and tetrahydrofuran had the smallest particle size, and the high alloying degree and the dispersion kept unchanged. Therefore, this kind of catalyst showed the highest catalytic activity and good stability for methanol electro-oxidation.
基金supported by the National Basic Research Program of China(2013CB934001)the Natural Science Foundation of Beijing(2051001)the Natural Science Foundation of China(51074011)
文摘Pd@Ru bimetallic nanoparticles deposited on carbon black electro-catalysts have been fabricated by microwave-assisted polyol reduction method and investigated for methanol electro-oxidation (MEO). The structure and electro-catalytic properties of the as-prepared catalysts were characterized by XRD, SEM, TEM and cyclic voltammetry (CV) techniques. The results showed that the introduction of Ru element (2-10 wt%) into Pd 20 wt%/C (hereafter, denoted as Pd/C) produced a series of core-shell structured binary catalysts. Pd@Ru 5 wt%/C (hereafter, denoted as Pd@Rus/C) catalyst displayed the highest catalytic activity towards MEO. And the mass activity of Pd@Ru5/C electrode catalyst at E = -0.038 V (vs. Hg/HgO) was 1.42 times higher than that of Pd/C electrode catalyst. In addition, the relationship between the catalytic stability for MEO on Pd@Ru/C catalysts and the value of dbp/dfp (the ratio of MEO peak current density in the negative scan and positive scan) were also investigated. The result demonstrated that Pd@Rus/C offering the smallest value of Jbp/Jfp displayed the best stable catalytic performance.
文摘A novel Fe-Pd bifunctional catalyst supported on mesh-type γ-Al<sub>2</sub>O<sub>3</sub>/Al was prepared and applied in the degradation of Rhodamine B (RhB). The monolithic mesh-type Fe-Pd/γ-Al<sub>2</sub>O<sub>3</sub>/Al bifunctional catalyst could be separated from the solution directly and could synthesize H<sub>2</sub>O<sub>2</sub> in situ. The characterization results showed that Fe could improve the dispersion of Pd<sup>0</sup>, and the electronic interactions between Pd and Fe could increase the Pd<sup>0</sup> contents on the catalyst, which increased the productivity of H<sub>2</sub>O<sub>2</sub>. Furthermore, DFT calculations proved that the addition of Fe could inhibit the dissociation of O<sub>2</sub> and promote the nondissociative hydrogenation of O<sub>2</sub> on the surface of Fe-Pd/γ-Al<sub>2</sub>O<sub>3</sub>/Al, which resulted in the increasement of H<sub>2</sub>O<sub>2</sub> selectivity. Finally, the in-situ synthesized H<sub>2</sub>O<sub>2</sub> by Pd was furtherly decomposed in situ by Fe to generate<span lang="EN-US" style="white-space:normal;font-size:10pt;font-family:;" "=""><span lang="EN-US" style="white-space:normal;font-size:10pt;font-family:;" "=""><span style="white-space:normal;color:#FFFFFF;font-family:Roboto, " background-color:#d46399;"=""><img src="Edit_e6a13073-7151-40b7-b2c3-a59a59d064fc.png" alt="" /></span></span></span>OH radicals to degrade organic pollutants. Therefore, Fe-Pd/ γ-Al<sub>2</sub>O<sub>3</sub>/Al catalysts exhibited excellent catalytic activity in the in-situ synthesis of H<sub>2</sub>O<sub>2</sub> and the degradation of RhB due to the synergistic effects between Pd and Fe on the catalyst. It provided a new idea for the design of bifunctional electro-Fenton catalysts. Ten cycles of experiments showed that the catalytic activity of Fe-Pd/γ-Al<sub>2</sub>O<sub>3</sub>/Al catalyst could be maintained for a long time.
基金This work was supported by the National Basic Research Program of Ministry of Science and Technology of China (No.2007CB210206), the National High Tech Research and Development Program (No.2009AA05Z435), and the National Natural Science Foundation of China (No.50772107).
文摘We reports an efficient approach for production of hydrogen from crude bio-oil and biomass char in the dual fixed-bed system by using the electrochemical catalytic reforming method. The maximal absolute hydrogen yield reached 110.9 g H2/kg dry biomass. The product gas was a mixed gas containing 72%H2, 26%CO2, 1.9%CO, and a trace amount of CH4. It was observed that adding biomass char (a by-product of pyrolysis of biomass) could remarkably increase the absolute H2 yield (about 20%-50%). The higher reforming temperature could enhance the steam reforming reaction of organic compounds in crude bio-oil and the reaction of CO and H20. In addition, the CuZn-Al2O3 catalyst in the water-gas shift bed could also increase the absolute H2 yield via shifting CO to CO2.
基金"TEQIP,COE Phase Ⅱ "in Jadavpur University for the support of this work
文摘One of the thrust areas of research is to find an alternative fuel to meet the increasing demand for energy.Glucose is a good source of alternative fuel for clean energy and is easily available in abundance from both naturally occurring plants and industrial processes.Electrochemical oxidation of glucose in fuel cell requires high electro-catalytic surface of the electrode to produce the clean electrical energy w ith minimum energy losses in the cell.Pt and Pt based alloys exhibit high electro-catalytic properties but they are expensive.For energy synthesis at economically cheap price,non Pt based inexpensive high electro catalytic material is required.Electro synthesized Zn O-Al2O3composite is found to exhibit high electro-catalytic properties for glucose oxidation.The Cyclic Voltammetry and Chronoamperometry curves reflect that the material is very much comparable to Pt as far as the maximum current and the steady state current delivered from the glucose oxidation are concerned.XRD image confirms the mixed oxide composite.SEM images morphology show increased 3D surface areas at higher magnification.This attributed high current delivered from electrochemical oxidation of glucose on this electrode surface.
基金This work was supported by the National Natural Scmnce Foundation of China(Grant Nos.20276069,20476097)
文摘Nanocrystalline tungsten carbide thin films were fabricated on graphite substrates by plasma enhanced chemical vapor deposition (PECVD) at H2 and Ar atmosphere, using WF6 and CH4 as precursors. The crystal phase, structure and chemical components of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectrometer (EDS), respectively. The results show that the film prepared at CH4/WF6 concentration ratio of 20 and at 800℃ is composed of spherical particles with a diameter of 20-35 nm. Electrochemical investigations show that the electrochemical real surface area of electrode of the film is large, and the electrode of the film exhibits higher electro-catalytic activity in the reaction of methanol oxidation. The designated constant current of the film catalyst is 123.6 mA/cm^2 in the mixture solution of H2SO4 and CH3OH at the concentration of 0.5 and 2.0 mol/L at 70℃, and the designated constant potential is only 0.306 V (vs SCE).
基金supported by JSPS KAKENHI(Grant number 24K15389)S.C.Kim greatly acknowledges the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education of the Republic of Korea(2020R1I1A3052258)for financial support.
文摘Surface area,pore properties,synergistic behavior,homogenous dispersion,and interactions between carbon matrix and metal-nanostructures are the key factors for achieving the better performance of carbon-metal based(electro)catalysts.However,the traditional hydro-or solvothermal preparation of(electro)catalysts,particularly,bi-or tri-metallic nanostructures anchored graphene(G)or carbon nanotubes(CNTs),often pose to poor metal–support interaction,low synergism,and patchy dispersion.At first,bimetallic flower-like-CuFeS_(2)/NG and cube-like-NiFeS_(2)/NCNTs nanocomposites were prepared by solvothermal method.The resultant bimetallic nanocomposites were employed to derive the 2D-nano-sandwiched Fe_(2)CuNiS_(4)/NGCNTs-SW(electro)catalyst by a very simple and green urea-mediated“mix-heat”method.The desired physicochemical properties of Fe_(2)CuNiS_(4)/NGCNTs-SW such as multiple active sites,strong metal-support interaction,homogenous dispersion and enhanced surface area were confirmed by various microscopic and spectroscopic techniques.To the best of our knowledge,this is the first urea-mediated“mix-heat”method for preparing 2D-nano-sandwiched carbon-metal-based(electro)catalysts.The Fe_(2)CuNiS_(4)/NGCNTs-SW was found to be highly effective for alkaline-mediated oxygen evolution reaction at low onset potential of 284.24 mV,and the stable current density of 10 mA cm^(−2) in 1.0 m KOH for 10 h.Further,the Fe_(2)CuNiS_(4)/NGCNTs-SW demonstrated excellent catalytic activity in the reduction of 4-nitrophenol with good kapp value of 87.71×10^(−2)s^(-1)and excellent reusability over five cycles.Overall,the developed urea-mediated“mix-heat”method is highly efficient for the preparation of metal-nanoarchitectures anchored 2D-nano-sandwiched(electro)catalysts with high synergism,uniform dispersion and excellent metal-support interaction.
文摘Anode electro-catalysts for direct dimethyl-ether fuel cell (DDFC), Pt/C, PtRu/C (1∶1) and PtSn/C (3∶2), were prepared by chemical impregnation-reductio n method with formaldehyde as the reductant. DME electro-oxidation and adsorptio n at Pt electrode and Pt electro-catalysts were investigated by Cyclic Voltammet ry(CV), Quasi-steady state polarization and Gas Chromatography(GC). CV showed th at there were two current peaks of DME electro-oxidation at Pt electrode around 0.8V (vs RHE); DME was adsorbed at Pt electrode more weakly and slowly than oxyg en, methanol, even hydrogen; the onset potential of DME oxidation was 50mV less than that of methanol, and DME peak potential 110 mV lower, thus more advantageo us for using in fuel cells than methanol. GC showed that small amount of HCHO wa s generated during DME electro-oxidation. The mechanism of DME electro-oxidation was proposed. Among the three electro-catalysts (Pt/C, PtRu/C and PtSn/C), Pt a lloy catalysts, especially PtRu/C, showed a higher performance toward DME electr o-oxidation, as in the case of methanol. Temperature experiments showed that bot h DME electro-oxidation and adsorption on Pt and Pt alloy catalysts were favored with increased temperature.