Control of the hydrogen absorption and desorption of rare-earth intermetallic compounds

The rate at which rare-earth intermetallic compounds absorb and desorb hydrogen can be controlled by ’’poisoning’’ the catalytic reaction, H2=2H. Specimens treated with SO2, a well-known catalytic ’’poison’’, are prevented from absorbing hydrogen for extended periods. More surprisingly, SO2 treatment after hydriding prevents hydrogen desorption by specimens for weeks. The applications of this process to energy storage are numerous.