The Effectiveness of Silver and Gold in Catalytic Homogenous and Heterogenous Borohydride Hydrolysis - a DFT Study.

Energy demands, and environmental aspects raised the need to study hydrogen-carrying material such as borohydride for the practical usage of hydrogen as a cleaner and more efficient fuel. A proper understanding of the hydrogen generation mechanism is a key requirement for the designing of efficient catalysts as the non-catalytic hydrolysis of borohydride in non-acidic media is a slow process. The hydrolysis mechanism of borohydride varies considerably using homogeneous and heterogenous catalysts. A comparison of the hydrolysis mechanism of borohydride using gold and silver as homogenous and heterogeneous catalyst is given in this review. Unexpectedly, with gold catalyst, Au+ or Au(111), only two steps of hydrolysis occur and BH(OH)2 is produced, while with silver catalyst, Ag+ or Ag(111), the hydrolysis can proceed to completion.