Low-temperature catalytic hydrogenation of silicon and germanium tetrachlorides on the modified nickel chloride

The catalytic reduction of SiCl4 and GeCl4 by hydrogen to silicon and germanium nanopowder was carried out over a modified nickel chloride catalyst. The effects of nickel chloride surface on the reaction were intensively investigated. The results show that modified nickel chloride surface play an important role in reduction the value of the activation energy and reaction temperature of the catalytic hydrogenation SiCl4 and GeCl4. Elemental analysis of the catalyst and reaction results demonstrate that the catalyst operates in a temperature range from 423 to 573 K. Further temperature increase above 623 K was impractical as it led to a change in catalyst composition and silicide/germanide is formed in reactor. The resulting knowledge has helped to assume the reaction mechanism which is based on the formation of SiCl2 and GeCl2 in the reaction zone. This study will be useful in understanding the reduction of SiCl4 and GeCl4 with hydrogen and provides information regarding the development of a SiCl4 converter for a Siemens reactor to produce poly-Si in the solar cell industry and produce Ge nanopowders with minimum energy consumption.