铑催化下铜在盐酸中的放氢反应

Evolution of Hydrogen over Copper in HCl Medium with Catalysis of Rhodium

纯铜片在盐酸中几乎不溶解,但若在铜片上镀有Rh后,Rh—Cu片在盐酸中可自发发生放氢反应。本文基于这一现象,采用测定Rh-Cu片在HCl中放氢体积之方法,考查了[Cl^-]、 [H^+]、温度等因素对Rh—Cu片放氢反应的影响,求得各动力学影响因素与放氢体积的关系式和反应活化能。从热力学角度解释了这一反应现象并提出了放氢反应机理。

The effects of the concentration of chlorine and hydrogen ions and temperature on the evolution of hydrogen over Rh-Cu sheet in HC1 medium are studied by means of the determination of volume of evoluted hydrogen. A formula to describe the relationship between there factors with the volume of evoluted hydrogen is deduced and reaction activation energy is calculated, to be 60kJ/mol. The thermodynamics is studied to explain the phenomenon of the evolution of hydrogen. The mechanism belongs to electrochemical step (fast) and electrochemical desorption step (slow) at the first 60 min, and then as the electrode potential increase to the equilibrium electrode potential for discharge of H^+, the mechanism is converted to composite desorption.