The Study of Thermochemical Hydrogen Preparation (II) Electrochemical Hydrid Cycle Using Sulfur-Iodine System

Abstract

Thermochemical water sphtting processes by use of sulfur compounds are presented，These processes are partly based on the thermal decomposition of sulfuric acid for the step evolving oxygen。Three hydrogen evolving steps were investigated；（1） C／／SO2，H2So4aq，H2／〆Pt，electrolysis （2） C／／SO2， H，SO、aq／1，，Hlaq／Pt，electrolysis（3）C／／SO2，H2SO4aq／12，Hlaq／／Pt，electrolysis without extemal electric poweL Activated charcoal was found to be favorable material for the anodic reaction．In the case（1），the cycle is completed with two reaction steps but still it needs some electric power．In the cases（2）and （3），a cation exchange membrane is used and an additional step（2HI→H2＋12）is necessary to produce hydrogen．The electric power required can be reduced compared with the case（！），and especially in the case（3），no electric power is required。 On the basis of the present study，some futur problems are proposed， Among the variety of thermochemical water