Base-metal catalysts based on porous layered double hydroxides for alkaline-free sodium borohydride hydrolysis

International audience; Catalyzed hydrolysis of sodium borohydride (SBH) has demonstrated promise for generation of a pure hydrogen stream for use with fuel cells. In designing an improved continuous hydrogen generator that uses the substantial heat released in the hydrolysis reaction to more effectively separate the sodium borate by-product, we sought a robust base-metal catalyst that could tolerate the exothermic reaction under flow conditions. Working under base-free conditions in ethanol solvent we identified reduced nickel and iron-containing particles supported on layered double hydroxides (LDHs) as robust catalysts. Catalytic activity was enhanced further using high surface area hierarchical supports prepared using the ‘inverse opal’ method. In particular, macroporous NiMgAl and FeMgAl LDHs produced 0.4 and 1.0 mol of hydrogen per minute per mole of active metal of the supported catalyst in aqueous ethanol solvent.