Hydriding/dehydriding properties of a series of LaNi₅ based alloys were compared by applying both hydrogen gas phase and electrochemical hydrogen charge/discharge methods. The highest hydrogen absorption capacity of 1.4 wt.% H₂ was found for LaNi_4.3Co_0.4Al_0.3, although LaNi_4.8Sn_0.2 also reveals comparable hydrogen capacity (>1.3%). A significant difference in the hydriding kinetics was observed for all studied alloys before and after activation. The activated alloys (5 cycles at 65 °C, 40 atm. H₂) reach their maximum capacities after less than a minute, whereas the pure LaNi₅ alloy needs several minutes for complete hydriding. The electrochemical hydriding/dehydriding behavior of the alloys reveals superior performance of LaNi_4.3Co_0.4Al_0.3 and LaNi_4.8Sn_0.2 compared to the other compositions studied, as the capacity of LaNi_4.8Sn_0.2 decreases by only 10% for 60 charge/discharge cycles at a current density of 100 mA/g. Good agreement between the hydrogen sorption kinetics of the alloys obtained electrochemically and from hydrogen gas phase has also been observed.

Described herewith is an electrochemical method to decontaminate sulphur compounds. Studies were carried out of sulphites (SO₃²⁻) oxidation on a range of anode catalysts. The electrocatalysts were characterized by scanning electron microscopy, XRD, XPS and BET. Polarization curves were recorded of electrodes incorporating lyophilized higher fullerenes and manganese oxides. The experiments showed that lyophilized higher fullerenes and C₆₀/C₇₀ fullerene catalysts in conjunction with manganese oxides electrochemically convert sulphites (SO₃²⁻) to sulphates (SO₄²⁻). The oxidation products do not poison the electrodes. The XPS analysis shows that the catalysts incorporating DWCNTs, MWCNTs and higher fullerenes have a higher concentration of sp³C carbon bonding leading to higher catalytic activity. It is ascertained that higher fullerenes play a major role in the synthesis of more effective catalysts. The electrodes built by incorporating lyophilized catalysts containing higher fullerenes and manganese oxides are shown as most promising in the effective electrochemical decontamination of industrial and natural wastewaters.