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 heterogeneous catalysts. A comparison of the hydrolysis mechanism of borohydride using gold and silver as homogenous and heterogeneous catalysts 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.