The kinetics of liquid-phase hydrogenation of benzene in misch metai nickel-five (MINi5) and benzene slurry system was studied by investigating the influences of the reaction temperature, pressure, alloy concentration...The kinetics of liquid-phase hydrogenation of benzene in misch metai nickel-five (MINi5) and benzene slurry system was studied by investigating the influences of the reaction temperature, pressure, alloy concentration and stirring speed on the mass transfer-reaction processes inside the slurry. The results show that the whole process is controlled by the reaction at the surface of the catalyst. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particles are negligible. The apparent reaction rate is zero order for benzene concentration and first order for hydrogen concentration in the liquid phase. The kinetic modei obtained fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of MINi5-C6H6 slurry system is 42.16kJ·mol-1.展开更多
The hydrogen adsorption on Pt-Rh alloys in sulfuric acid aqueous solutions was studied by the method of cathode pulses. Hydrogen adsorption on the electrode with all ratio of alloy components (ωRh = 0-100%) is well d...The hydrogen adsorption on Pt-Rh alloys in sulfuric acid aqueous solutions was studied by the method of cathode pulses. Hydrogen adsorption on the electrode with all ratio of alloy components (ωRh = 0-100%) is well described by the Temkin logarithmic isotherm. The surface coverage by adsorbed hydrogen at the same potential is decreased with increasing content of rhodium in the system. A linear dependence of adsorption peak potential on the alloy compositions in the case of weakly bonded adsorbed hydrogen is established. Hydrogen adsorption heat as a function of surface coverage for Pt-Rh-electrodes was obtained. The shape of the current-potential curve and position of the weakly bonded hydrogen adsorption on the potential scale are all related to alloy compositions, thus can serve as the basis for the determination surface composition of alloys.展开更多
The diversities of hydrogen sorption properties of Mg2FeH6-based complexes with and without TiO2 were investigated. Mg2FeH6-based complexes with and without TiO2 were synthesized respectively by reactive mechanical al...The diversities of hydrogen sorption properties of Mg2FeH6-based complexes with and without TiO2 were investigated. Mg2FeH6-based complexes with and without TiO2 were synthesized respectively by reactive mechanical alloying,and hydrogen sorption properties of the complexes were examined by Sieverts-type apparatus. The results show that the sample without TiO2 releases 4.43 % (mass fraction) hydrogen in 1.5 ks at 653 K under 0.1 MPa H2 pressure and absorbs 90% of the total 4.43 % (mass fraction) hydrogen absorbed in 85 s at 623 K under 4.0 MPa H2 pressure. But for the sample with TiO2 addition under the same condition,it only needs 400 s to release all of the stored hydrogen and 60 s to absorb 90% of the total hydrogen absorbed. The activation energies for desorption process of the samples with and without TiO2 are determined to be 71.2 and 80.3 kJ/(mol.K),respectively. The improvement in hydrogen sorption rate and and reduction in activation energy can be attributed to the addition of TiO2.展开更多
基金State Key Project of Basic Research of China(TG2000026406)National Natural Science Foundation of China(No.50071053)
文摘The kinetics of liquid-phase hydrogenation of benzene in misch metai nickel-five (MINi5) and benzene slurry system was studied by investigating the influences of the reaction temperature, pressure, alloy concentration and stirring speed on the mass transfer-reaction processes inside the slurry. The results show that the whole process is controlled by the reaction at the surface of the catalyst. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particles are negligible. The apparent reaction rate is zero order for benzene concentration and first order for hydrogen concentration in the liquid phase. The kinetic modei obtained fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of MINi5-C6H6 slurry system is 42.16kJ·mol-1.
文摘The hydrogen adsorption on Pt-Rh alloys in sulfuric acid aqueous solutions was studied by the method of cathode pulses. Hydrogen adsorption on the electrode with all ratio of alloy components (ωRh = 0-100%) is well described by the Temkin logarithmic isotherm. The surface coverage by adsorbed hydrogen at the same potential is decreased with increasing content of rhodium in the system. A linear dependence of adsorption peak potential on the alloy compositions in the case of weakly bonded adsorbed hydrogen is established. Hydrogen adsorption heat as a function of surface coverage for Pt-Rh-electrodes was obtained. The shape of the current-potential curve and position of the weakly bonded hydrogen adsorption on the potential scale are all related to alloy compositions, thus can serve as the basis for the determination surface composition of alloys.
基金Project (50574105) supported by the National Natural Science Foundation of ChinaProject (NCET-06-0683) supported by the Program for the New Century Excellent Talents in University+1 种基金Project (08-030239) supported by the Program for 121 Excellent Talents in Hunan ProvinceProject (07MX21) supported by Mittal Student Innovation Foundation of Central South University
文摘The diversities of hydrogen sorption properties of Mg2FeH6-based complexes with and without TiO2 were investigated. Mg2FeH6-based complexes with and without TiO2 were synthesized respectively by reactive mechanical alloying,and hydrogen sorption properties of the complexes were examined by Sieverts-type apparatus. The results show that the sample without TiO2 releases 4.43 % (mass fraction) hydrogen in 1.5 ks at 653 K under 0.1 MPa H2 pressure and absorbs 90% of the total 4.43 % (mass fraction) hydrogen absorbed in 85 s at 623 K under 4.0 MPa H2 pressure. But for the sample with TiO2 addition under the same condition,it only needs 400 s to release all of the stored hydrogen and 60 s to absorb 90% of the total hydrogen absorbed. The activation energies for desorption process of the samples with and without TiO2 are determined to be 71.2 and 80.3 kJ/(mol.K),respectively. The improvement in hydrogen sorption rate and and reduction in activation energy can be attributed to the addition of TiO2.
