Progress in sodium borohydride as a hydrogen storage material: Development of hydrolysis catalysts and reaction systems

High volume hydrogen production from the hydrolysis of sodium borohydride using a cobalt catalyst supported on a honeycomb matrix

“…The volume required to store 4 kg of hydrogen gas in compressed cylinders at 200 bar is about 225 L. The production and storage of liquefied H 2 is costly, as it requires high-energy input and sophisticated equipment. Alternatively, the use of sodium borohydride (NaBH 4 , SBH) as a potential hydrogen storage material has attracted significant interest from the late 1990s by virtue of its high Gravimetric Hydrogen Storage Capacity (GHSC) [1,3]. Hydrogen gas can be released from SBH by hydrolysis in the presence of water forming sodium metaborate (NaBO 2 ) and heat (Eq.…”

“…(1)) NaBH 4 þ ð2 þ xÞH 2 O/NaBO 2 $x H 2 O þ 4H 2 þ $ 300 kJ=mol (1) The value of GHSC depends upon the hydration state of the NaBO 2 by-product (GHSC ¼ 10.8% with x ¼ 0; GHSC ¼ 7.3% with x ¼ 2 and GHSC ¼ 5.5% with x ¼ 4). The most common hydration state of sodium metaborate is two [4]. For practical application of the NaBH 4 eH 2 O system for hydrogen generation in a controlled manner, one has to take into account also the stability of NaBH 4 solutions given the thermodynamic spontaneity of reaction (1).…”

“…The most common hydration state of sodium metaborate is two [4]. For practical application of the NaBH 4 eH 2 O system for hydrogen generation in a controlled manner, one has to take into account also the stability of NaBH 4 solutions given the thermodynamic spontaneity of reaction (1). For this reason alkali metal hydroxides, generally sodium or potassium hydroxides (NaOH or KOH) are used to stabilize NaBH 4 in aqueous solutions.…”

“…In order to avoid this deactivation process an initial NaBH 4 concentration lower than 16 g in 100 g of water is generally used [10,15]. A number of studies have been published dealing with both the catalytic activity and long-term stability of Co 2 eB catalysts doped with either Cr or W [1,4,5,7,13,16,17]. Cobalt oxides have also been extensively studied [14,18,19] Several types of reactors, both static and dynamic have been designed to exploit the SBH reaction.…”

Magnetically-actuated mesoporous nanowires for enhanced heterogeneous catalysis

“…Despite this limitation, the values for the hydrogen generation activity are far better than in many other catalysts and are actually comparable to the more competitive state-of-the-art solid catalysts based on noble metals [47,[81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97] (Table S4). In addition, this approach offers the relevant advantage of reducing the Pt content (i.e., cost-effectiveness) and the important benefits from the magnetic behaviour of the catalysts, i.e., easy manipulation, recyclability and improved catalytic performance.…”