Electrochemical Construction of Hydrogenation System Using Active Hydrogen at Hydrogen Storage Alloy/Gas Interphase

从这项工作中获得的信息可概括如下1.MmNi&lt；4.2&gt；Al_&lt；0.5&gt；M_&lt；0.3&gt；(mm=混合稀土，M=Cr，Mn，Fe，Co，Ni)合金中的氢扩散系数(爱因斯坦扩散系数)随着M原子半径的增大而减小，这是因为它们中吸附的氢的稳定性增强。此外，无论x值如何，在Mm(B5)x(B_5=Ni_&lt；3.6&gt；Mn_&lt；0.4&gt；Al_&lt；0.3&gt；Co_&lt；0.7&gt；，0.8*x*1.12)合金电极上的析氢反应均按Volmer-Tafel机理进行。X值的增加有效地抑制了Tafel反应，促进了合金中的吸氢。用Pd片电极隔开的两室槽构建了一个新的连续加氢体系。在适当的诱导期后，乙苯的产生量呈线性增长，乙苯生产的电流效率可达90%以上。乙苯的生成率随着电解水电流密度的增加而增加。利用快淬法制备的储氢合金薄片电极也可以构建氢化体系。上述加氢体系可用于α-甲基苯乙烯、1-辛烯、2-辛烯和环己烯的加氢，加氢速率按cyclohexene&lt；2-octene&lt；alpha-methylstirene&lt；1-octene&lt；stirene.的顺序递增气态不饱和有机化合物乙炔的加氢反应也在进行，乙烷是通过乙烯生成的。Pd黑对氢化反应具有很高的催化活性，它可以通过Pd和活性氢通过Pd片电极的反应以三维方式沉积。与Pd片电极相比，4-甲基苯乙烯和2-辛烯在Pd片电极上的加氢速率显著提高。

The information obtained from this work can be summarized as follows.1. Hydrogen diffusion coefficient (Einstein diffusion coefficient) in MmNi_<4.2>Al_<0.5>M_<0.3> (Mm=misch metal, M=Cr, Mn, Fe, Co, Ni) alloys decreases with an increase in atomic radius of M because of enhanced stability of absorbed hydrogen in them. In addition, hydrogen evolution reaction at Mm(B_5)_x (B_5=Ni_<3.6>Mn_<0.4>Al_<0.3>Co_<0.7>,0.8*x*1.12) alloy electrodes proceeds via the Volmer-Tafel mechanism irrespective of x value. An increase in x value depresses the Tafel reaction effectively, leading to promotion of hydrogen absorption in the alloys.2. A new successive system for hydrogenation of stirene was constructed using a two-compartment cell separated by a Pd sheet electrode. The amount of produced ethylbenzene increases linearly after an appropriate induction period and current efficiency for ethylbenzene production is over 90%. The rate of ethylbenzene production increases with an increase in current density for electrolysis of water. The hydrogenation system can be also constructed by using hydrogen storage alloy sheet electrodes prepared by rapid-quenching method.3. The above-mentioned hydrogenation system can be applied to the hydrogenation of alpha-methylstirene, 1-octene, 2-octene and cyclohexene, and the hydrogenation rate increases in the order of cyclohexene<2-octene<alpha-methylstirene<1-octene<stirene. The hydrogenation of acetylene, gaseous unsaturated organic compound, also proceeds and ethane is produced via ethylene.4. Pd black, which is well-known to show high catalytic activity for the hydrogenation, can be deposited three-dimensionally by a reaction of Pd^<2+> with active hydrogen passing through a Pd sheet electrode. The hydrogenation rates of 4-methylstirene and 2-octene using a palladinized Pd sheet electrode increase markedly in comparison with those using a Pd sheet electrode.