Hydrogen production from sodium borohydride on a Ni-Ru catalyst : an electroche...

• Author(s): Rangel, C. M. ; Fernandes, Vitor R. ; Ferreira, M. J. F. ; Pinto, A. M. F. R. ; Hashimoto, T. ; Thompson, G. E.
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.9/1478
• Origin: Repositório do LNEG
• Document Type: Conference Object
• Language: English

Description

Previous work by the authors has demonstrated a high rate and high yield hydrolysis of sodium borohydride, in the presence of a Ni-Ru catalyst synthesized by wet chemistry. The catalyst has been fully characterized and utilized more than 300 times exhibiting high stability and durability. In this work, results of an electrochemical study are reported using the powder catalyst supported on a Ni foam in order to measure the open circuit potential during hydrogen production and to study the reaction using voltammetry and ac impedance. Production rates were as high as 10 Lmin-1gcat -1 at 65ºC. Electrochemical studies indicated that the hydrogen evolution mechanism corresponds to a Volmer- Heyrovsky type, suggested by a Tafel slope of 117 mVdec-1. Tafel region potentials are in agreement with values found for hydrolysis at the open circuit. The Langmuir-Hinshelwood mechanism explains the hydrolysis of sodium borohydride using a Ni-Ru catalyst. The role of Ni and Ru is briefly discussed.