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Catal. Sustain. Energy 2018; 5: 41–48

Short communication

Olga V. Netskina*, Tihon N. Filippov, Oksana V. Komova, Valentina I. Simagina generation by both acidic and catalytic hydrolysis of https://doi.org/10.1515/cse-2018-0006 most closely satisfy these severe requirements [8-13]. First, Received October 9, 2018; accepted October 16, 2018 they have no rivals in the mass content of hydrogen. For Abstract: tablets have been employed example, potassium borohydride, sodium borohydride as hydrogen-storage materials. Hydrogen release was and have hydrogen densities of 0.083, performed by acidic hydrolysis where of sulfuric 0.112 and 0.145 g·cm-3, respectively, which exceeds the and hydrochloric were added to the tablets, and value for liquefied hydrogen (0.07 g·cm-3). Second, by catalytic hydrolysis where water was added tablets interaction with water increases the hydrogen yield of -state NaBH4/Co composite. In acidic solutions twofold, water being involved in the gas generation. hydrogen evolution occurred instantaneously, and at high concentrations of acids the releasing hydrogen contained an MH n + nH2O → M(OH )n + nH2  , (1) (1) admixture of . Hydrogen evolution from the solid- where M is an alkali or alkaline-earth metal. state NaBH4/Co composite proceeded at a uniform rate of 4CoCl + 8NaBH + 18H O ⎯⎯→ (4Co : 2B) + 6B(OH ) + 8NaCl + 25H  (2) 13.8±0.1 cm3·min-1, water vapor being the only impurity in the However, hydrolysis2 of hydrides4 is not2 a totally safe catalyst 3 2 evolving gas. process, since it evolves a large amount of heat per of -1 -1 hydrogen: 2LiHBH –3 145→ kJ·molB2 H6; MgH 2 – 160 kJ·mol ; LiBH 4 – (4) -1 -1 -1 Keywords: Hydrogen, sodium borohydride, 90 kJ·mol ; LiAlH4 – 150 kJ·mol ; NaAlH4 – 142 kJ·mol ; AlH3 ­ hydrolysis, diborane, catalyst hydrolysis 156 kJ·mol-1; CaH – 140 kJ·mol-1; NaH – 152 kJ·mol-1 [14,15]. 2NaBH2 + H SO → Na SO + B H + 2H  (5) Unlike most ,4 sodium2 4 borohydride2 4 interaction2 6 2 with water has a comparatively small heat effect (80 kJ

per mole of2NaBH hydrogen)4 + so2 HClthat its→ complete2NaCl conversion+ B2 H6 + can2H 2  (6) 1 Introduction be achieved either at temperatures above 110 °С and in the presence of vapors of hydrochloric or acetic acids [16], The development of compact hydrogen sources is an + → +  or over metalBH catalysts3 3H 2[17,18]O whichB(OH opens)3 the3H possibility2 (7) important direction of hydrogen energy research [1-7]. of the control of the process of hydrogen generation. Compact hydrogen sources must provide high yields Inexpensive but active+ +catalysts are→ most often+ +  of hydrogen per unit of mass or volume without any 2NaBH 4 6H2O H2SO4 Na 2SO4 2B(OH )3 8H2 (8) used [19,20]. Acid catalysts prepared by modifying the additional heating, as well as purification of hydrogen support with sulfuric [21], boric, and citric [22] acids are from compounds that act as catalytic poisons for + + → + +  also efficientNaBH in 4hydrogen3H2O generationHCl fromNaCl solutionsB(OH of )3 4H2 (9) electrodes of low-temperature exchange membrane sodium borohydride. fuel cells, requirements strongly narrowing the range of Along with the+ catalytic→ sodium borohydride+  hydrogen-generating materials suitable for energy-carrier NaBH 4 4H 2O NaB(OH )4 4H 2 (10) hydrolysis, hydrogen generation by adding inorganic or applications. Binary and complex hydrides of alkali metals organic acids to a of this hydride has also been discussed in the literature [23-25]. It has been demonstrated *Corresponding author: Olga V. Netskina, Laboratory of Hydrides that the addition of a weak solution (0.25 M) of phosphoric Investigation, Boreskov Institute of SB RAS, Pr. Akademika acid to sodium borohydride in the presence of a copper Lavrentieva 5, Novosibirsk, 630090, Russia, [email protected] catalyst which has a low activity to a substantial Tihon N. Filippov, Photocatalysis group, Boreskov Institute of Cata- growth in the hydrogen generation rate [26]. Nevertheless lysis SB RAS, Pr. Akademika Lavrentieva 5, Novosibirsk, 630090, Russia in dilute solutions of acids, complete conversion of this Oksana V. Komova, Valentina I. Simagina, Laboratory of Hydrides hydride could not be achieved without catalysts and Investigation, Boreskov Institute of Catalysis SB RAS, Pr. Akademika increased concentrations of acids were used to increase Lavrentieva 5, Novosibirsk, 630090, Russia

Open Access. © 2018 Olga V. Netskina et al., published by De Gruyter. This work is licensed under the Creative Commons Attribution- NonCommercial-NoDerivs 4.0 License.

1 42 O.V. Netskina, et al. the hydrogen yield and the rate of gas generation [27]. No 7791-13-1, 97 wt%) in a 0.12 М aqueous solution of An XRD analysis of the non-gaseous products of the sodiumMH n borohydride+ nH2O → Mat( OH40 )°Сn +withnH 2constant , stirring (1) interaction of sodium borohydride with acids has shown at 400 rpm. The Co:NaBH4 mole ratio was 1:25. them to be sodium boratesMH +andnH sodiumO → M salts(OH )of+ thenH  , (1) n 2 n 2 4CoCl2 + 8NaBH 4 + 18H 2O ⎯⎯→ (4Co : 2B)catalyst + 6B(OH )3 + 8NaCl + 25H 2  (2) corresponding acids [28]. According to a chromatographic analysis, the hydrogen-containing4CoCl + gas8NaBH did not+ contain18H O any⎯⎯ → (4Co : 2B) + 6B(OH ) + 8NaCl + 25H  (2) (2) 2 4 2 catalyst→  3 2 impurities even in the case of hydrochloric acid [29]. This 2BH 3 B2 H6 (4) result is doubtful and needs additional investigation since After gas evolution the black ferromagnetic catalyst 2BH 3 → B2 H6  (4) easily evaporates and is always present precipitate2NaBH 4was+ Hseparated2SO4 → Nafrom2SO the4 +reactionB2 H6 + medium,2H2  (5) above a hydrochloric acid solution. washed with acetone (CAS No 67-64-1, 99 wt%) and dried 2NaBH 4 + H2SO4 → Na 2SO4 + B2 H6 + 2H2  (5) Despite the convenienceof aqueous sodium in a2 vacuumNaBH box+ 2 atHCl 70 →°С for2NaCl 2 hr. The+ B synthesizedH + 2H cobalt (6) borohydride solutions for hydrogen generation by catalyst was4 stored in desiccators under2 argon6 to prevent2 + → + +  acidic and catalytic hydrolysis,2NaBH 4 in 2storageHCl the2NaCl sodiumB2 Hits6 oxidation2H2 by air. The reduction of the cobalt catalyst (6) borohydride slowly interacts with water even in the by sodiumBH 3 + borohydride3H2O → B leads(OH to)3 the+ 3 formationH2  of spherical (7) presence of sodium hydroxideBH 3 [30-32].+ 3H2O This→ Bnot(OH only)3 +leads3H2 particles (average size 30 nm) consisting of a core of (7) to a reduction in hydrogen content but also to changes in amorphous cobalt- and an -containing shell 2NaBH 4 + 6H2O + H2SO4 → Na 2SO4 + 2B(OH )3 + 8H2  (8) the character of the in situ2NaBH reduction4 + 6H of2 Ocobalt+ H2 SOcatalysts4 → Na 2(thicknessSO4 + 2B (3-5OH nm).)3 + 8InH an2  earlier study the molar ratio of (8) because of the forming sodium tetrahydroxoborate [33]. the elements in such cobalt-boron catalysts was found NaBH + 3H O + HCl → NaCl + B(OH ) + 4H  (9) Considering the instability of sodium borohydride to be Co:B:O:H=3.2:1.5:1.4:14 2 [39]. The physicochemical3 2 NaBH 4 + 3H2O + HCl → NaCl + B(OH )3 + 4H2  (9) solutions it was suggested that this hydride in the form of properties of the prepared cobalt catalyst have been tablets may be stored and used for hydrogen generation describedNaBH in4 + detail4H 2 elsewhereO → NaB [39,40].(OH )4 + 4H 2  (10) NaBH 4 + 4H 2O → NaB(OH )4 + 4H 2  (10) [34-37]. The advantages of such an approach are: high The elemental composition of the catalyst was content of hydrogen (up to 10 wt %), the absence of an identified by atomic-emission spectroscopy with alkali, no losses of hydrogen in storage, simplicity of inductively-coupled plasma on an Optima 4300V operation using water from any natural source, as well instrument (Germany). The relative error of determination as the possibility to vary the rate of gas generation by of cobalt and boron did not exceed 5 %. varying the amounts of the added inexpensive cobalt For the hydrogen generation kinetic study, the tablets catalyst [38]. It is important to consider the composition were placed into a temperature-controlled glass reactor at 3 of the gas evolving from the NaBH4 tablet when used as 40 °С and then 5 cm of water or an acid solution of a given a hydrogen source since impurities can poison concentration (H2SO4 – from 6.2 to 98 wt%, CAS No 7664- electrodes catalytically. To date, little attention has been 93-9; HCl – 34 wt%, CAS No 7647-01-0) was added. The paid to this issue in the literature. Also, there have been volume of the evolving gas was determined volumetrically no publications comparing the efficiencies of hydrogen using a gas burette and reduced to normal conditions generation from solid-state compositions of NaBH4 by (N refers to normal conditions, i.e., 0°C, 1 atm). Each acidic and catalytic hydrolysis. experiment was repeated three times and the average The aims of this work are (I) to compare the kinetic values were taken to construct the kinetic dependences. regularities of hydrogen generation from sodium The relative experimental error did not exceed 2 %. borohydride tablets in solutions of acids with different The qualitative analysis of the hydrogen-containing concentrations and from NaBH4/Co tablets upon addition gas was performed on a Nicolet 380 IR-spectrometer of water and (II) to determine the qualitative composition (Thermo Scientific, USA). The spectrometer was equipped of the forming hydrogen-containing gas. with a gas cell with an optical path length of 10 cm. The scan space was from 900 to 4000 cm-1, the resolution was 1 cm-1. Each spectrum was averaged over 64 scans. The 2 Methods absorption bands were assigned using the NIST Chemistry WebBook [41]. To prepare the tablets, a powder of sodium borohydride (CAS No 16940-66-2, 98 wt%) – 0.0352 g and a mechanical mixture of this hydride – 0.0352 g with a cobalt catalyst 3 Results and Discussion – 0.0117 g ((4Co:2B)catalyst in equation (2)) were pressed in a PRG-400 hydraulic press (Russia). The cobalt catalyst The kinetics of hydrogen evolution upon the addition was prepared by the reduction of cobalt chloride (CAS of sulfuric or hydrochloric acids to tablets of sodium 1

1 Hydrogen generation by both acidic and catalytic hydrolysis of sodium borohydride 43

Figure 1. Solid-state (a) NaBH4 and (b) NaBH4/Co tablets. borohydride (Fig. 1a) was compared with that upon the addition of water to tablets of a solid-state NaBH4/Co composite (Fig. 1b). The interaction of sodium borohydride with acids has been demonstrated to proceed very swiftly (Fig. 2). The reaction was completed within 10 seconds. Addition of a diluted solution (6.2 wt %) led to the evolution of 83 Ncm3 of hydrogen-containing gas which corresponds to complete hydride conversion. An IR analysis has shown that the evolved gas (Fig. 3) did not contain impurities other than water vapor since in the IR spectrum only the vibrations of deformational vibrations Н–О–Н at 1600 cm-1 are observed [42-44]. Unlike the heterogeneous catalysts [45,46], the acids are reagents which are used up during reaction. For Figure 2. Acidic and catalytic hydrolysis of sodium borohydride. smaller volumes of acids more concentrated solutions were used [27,28]. Our investigations (Fig. 2) have shown that the volume of the evolving gas decreased with an increasing concentration of sulfuric acid. First of all, this may be caused by the formation of diborane, the presence of which, in the hydrogen-containing gas, was confirmed by IR spectroscopy (Fig. 3). IR spectra of gaseous products formed in the presence of a highly-concentrated acid show a series of absorption bands at 970, 1170, 1600, 1870, 2520 and 2610 cm-1 characteristic of diborane (Table 1). The obtained results are in good agreement with the mechanism of interaction of sodium borohydride with acids in diluted and concentrated solutions. According to [50-53], in an acid medium the interaction of a proton with the borohydride anion occurs via the formation + ¯ of an intermediate complex H2BH3 (or H ×BH4 ) which decomposes to form molecular hydrogen and borane. Figure 3. IR spectra of hydrogen-containing gas generated by acidic and catalytic hydrolysis of sodium borohydride. 44 O.V. Netskina, et al.

Table 1. Vibration frequencies of diborane [47-49]. Frequency, cm-1 Intensity Symmetry* Mode Character of diborane vibration

960…980 strong B2u n14

1160…1180 very strong B3u n18

1580…1610 very strong B3u n17

1860…1880 strong B2u n13

2510…2570 very strong B3u n16

MH n + nH2O → M(OH )n + nH2  , (1) 2610…2630 strong B n 1u 8 4CoCl2 + 8NaBH 4 + 18H 2O ⎯⎯→ (4Co : 2B)catalyst + 6B(OH )3 + 8NaCl + 25H 2  (2)

MH n + nH2O → M(OH )n + nH2  , (1) 2BH 3 → B2 H6  (4) *B – antisymmetric with respect to the main axis of symmetry. 4CoCl2 + 8NaBH 4 + 18H 2O ⎯⎯→ (4Co : 2B)catalyst + 6B(OH )3 + 8NaCl + 25H 2  (2) – hydrogen; – boron. 2NaBH 4 + H2SO4 → Na 2SO4 + B2 H6 + 2H2  (5) + → +  MH n nH2O2BHM(OH→)Bn HnH2 , (1) (4) + 3 → 2 6 + +  (6) (6) H2 BH 3  BH 3 + H2  (3) 2NaBH 4 2HCl 2NaCl B2 H6 2H 2 (3)

The formation of borane (BH ) has been confirmed 4CoCl2 + 8NaBH 4 + 18H 2O ⎯⎯→ (4Co : 2B)catalyst + 6B(OH )3 + 8NaCl + 25H 2  (2) MH + nH O → M3 (OH ) + nH  , In this case,2 theNaBH hydrogen + HsourcesSO are→ sodium Na SO borohydride + B H + 2H(1) (5) experimentally byn converting2 it to trimethylaminen borane2 BH + 3H O →4B(OH2) +43H  2 4 2 6 2 (7) The formation of borane (BH3) has been andconfirmed acid.3 experim2 entally3 by converting2 it to trimethylamine [54] and sodium trihydrocyanoborate [55]. In concentrated 2BH 3 → B2 H6  (4) In dilute acids BH was instantly hydrolized which acids (sulfuric, phosphoric and others) dimerization of 3 4CoCl2 + 8NaBH 4 + 18H 2O ⎯⎯→ (4Co : 2B)catalyst2+NaBH6B(OH4 +)23 HCl+ 8NaCl→ 2NaCl+ 25H+2 B2 H6 + 2H2 (2) (6) borane [54] and sodium trihydrocyanoborateincreased2NaBH [55 4the].+ 6InhydrogenH 2 concentratedO + Hcontent2SO4 →in acids theNa 2forming SO(sulfuric,4 + 2gasB( OH[59],phosphoric) 3 + 8H2  and (8) borane was observed. 2NaBH 4 + H2SO4 → Na 2SO4 + B2 H6 + 2H2  (5) since water is an additional source of hydrogen: MH + nH O → M(OH ) + nH  , (4) (1) n others)2 dimerization→ n  of2 borane was observed. BH + 3H O → B(OH ) + 3H  (7) (7) 2BH 3 B2 H6 2NaBHNaBH 4 4++2 HCl3H23→O2+ NaClHCl2 +→B 2 HNaCl6 + 2H +2 B3 ( OH )32 + 4 H 2  (4) (6) (9) Such an+ approach has+ often been⎯⎯ employed→ to prepare + + +  4CoCl2 28BHNaBH→4 B18HH 2O (4Co : 2B)catalyst 6BHB( OHHence,+ 3)H3 O in8 →NaCldiluteB(OH solutions)25+H3H2 the reaction (2)between the (4) (7) diborane under laboratory3 2 conditions6 [58]. Hence, in 3 +2 →+3 2 + + → + +  (8) 2NaBH 4 + H2SO4 → Na 2SO4 + B2 H6 +acid2NaBHH and2  4hydride 2 4NaBHH 2 canO 4 be NaBdescribed6H( 2OHO )as4H follows 2SO4H42 [28]: Na 2SO 4 2B(5(OH) )3 8H2 (10) highly concentrated solutions the interaction between the →  2NaBH + 6H O + H SO → Na SO + 2B(OH ) + 8H  (8) acid2 BHand3 sodiumSuchB2 H borohydride 6 an approach is described has often by the been equation employed to4 prepare 2 diborane2 4 under2 4 laboratory(4) 3 conditions2 [58]. + + → + +  (9) [56,57]: 2NaBH 4 + 2HCl → 2NaCl + B2 H6 + 2H2  NaBH 4 3H2O HCl NaCl B( OH )3 (64) H2 + + → + +  (8) (5) NaBH 4 3H2O HCl NaCl B(OH )3 4H2 (9) 2NaBH 4Hence,+ H2SO in4 →highlyNa 2SO concentrated4 + B2 H6 + 2 solutionsH2  the interaction between the acid and( 5sodium) borohydride is + → +  BH 3 + 3H2O → B(OH )3 + 3H2  NaBH 4 4H 2O NaB (OH ) 4 4H 2 (7) (10) NaBH 4 + 4H 2O → NaB(OH )4 + 4H 2  (10) 2NaBH 4described+ 2HCl → by2NaCl the equation+ B2 H6 +[526H,527]: (6) 2NaBH + 6H O + H SO → Na SO + 2B(OH ) + 8H  (8) 4 + 2 → 2 4 + 2 4 +  3 2 BH 3 + 32HNaBH2O → 4B(OHH)23SO+ 43H2 Na 2SO4 B2 H 6 2H 2 (7) (5) NaBH + 3H O + HCl → NaCl + B(OH ) + 4H  (9) + 4 + 2 → + + 3  2 2NaBH 4 2NaBH6H2O4 +H22HClSO4 →Na2NaCl2SO4 + 2BB2(HOH6 +)32H82H2 (8) (6)

NaBH 4 + 4H 2O → NaB(OH )4 + 4H 2  (10) NaBH 4 +In3 thisH2O case,+ HCl the→ hydrogenNaCl + B (sourceOH )3 s+ are4H 2sodium borohydride and acid. (9)

NaBH 4 +In4 diluteH 2O → acidsNaB (BHOH3) was4 + 4 iHnstantly2  hydrolize d which increase d the hydrogen content(10) in the forming gas

[59], since water is an additional source of hydrogen:

BH 3 + 3H2O → B(OH )3 + 3H2  (7)

Hence, in dilute solutions the reaction between the acid and hydride can be described as follows [28]:

2NaBH 4 + 6H2O + H2SO4 → Na 2SO4 + 2B(OH )3 + 8H2  (8)

NaBH 4 + 3H2O + HCl → NaCl + B(OH )3 + 4H2  (9)

Thus, in our work, when the concentration of sulfuric acid was reduced (Fig. 2) the dimerization of

borane was suppressed by the hydrolysis of borane in excess water. This is also the reason for the 1 1 reduction of diborane in the hydrogen-containing gas.

It should be noted that the gas forming in highly concentrated solutions of sulfuric and hydrochloric

acids also contains, apart from the diborane, impurities of sulfur oxides and hydrogen chloride, 1 respectively. The presence of sulfur oxides is indicated by observation of the absorption band

at 1410 cm-1 [60] while the presence of hydrogen chloride follows from the absorption at 2600 to

1 1

MH n + nH2O → M(OH )n + nH2  , (1)

4CoCl2 + 8NaBH 4 + 18H 2O ⎯⎯→ (4Co : 2B)catalyst + 6B(OH )3 + 8NaCl + 25H 2  (2)

2BH 3 → B2 H6  (4)

2NaBH 4 + H2SO4 → Na 2SO4 + B2 H6 + 2H2  (5)

2NaBH 4 + 2HCl → 2NaCl + B2 H6 + 2H2  (6)

BH 3 + 3H2O → B(OH )3 + 3H2  (7) Hydrogen generation by both acidic and catalytic hydrolysis of sodium borohydride 45

2NaBH 4 + 6H2O + H2SO4 → Na 2SO4 + 2B(OH )3 + 8H2  (8) 4 Conclusions NaBH 4 + 3H2O + HCl → NaCl + B(OH )3 + 4H2  (9) (9) The kinetic regularities of the release of hydrogen from NaBHThus,+ in4 HourO work,→ NaB when(OH the) concentration+ 4H  of sulfuric (10) MH4 + nH2 O → M(OH4 ) +2 nH  , sodium borohydride tablets upon addition of sulfuric or(1) acid was reducedn (Fig.2 2) the dimerizationn of2 borane was hydrochloric acids, and from tablets that are a mixture of suppressed by the hydrolysis of borane in excess water. sodium borohydride and a cobalt catalyst upon addition This is4CoCl also the+ reason8NaBH for the+ reduction18H O ⎯of⎯ diborane→ (4Co in: the2B ) + 6B(OH ) + 8NaCl + 25H  (2) 2 4 2 catalystof water have been3 studied. It was demonstrated2 that in hydrogen-containing gas. solutions of acids the conversion of the hydride proceeded It should be noted that the gas forming in highly 2BH → B H  swiftly. The reaction time was less than 10 seconds. In(4) concentrated3 solutions2 6 of sulfuric and hydrochloric the 6.2 wt% solution of sulfuric acid the released gas acids also contains, apart from the diborane, impurities contained only water vapors. In more concentrated of sulfur2NaBH oxides +andH hydrogenSO → chloride,Na SO respectively.+ B H + The2H  (5) 4 2 4 2 4 2 6 2 solutions a quantity of diborane was observed that presence of sulfur oxides is indicated by observation of increased with increasing acid content. This shows that the absorption band at 1410 cm-1 [60] while the presence of 2NaBH + 2HCl → 2NaCl + B H + 2H  in highly concentrated acid solutions the dimerization ( 6) hydrogen chloride4 follows from the absorption2 6 at 2600 2to of borane (as an intermediate) takes place, giving the 3100 cm-1 [61,62]. The presence of such impurities means presence of diborane in the hydrogen-containing gas. that the hydrogen-containing+ → gas must+ be purified before (7) BH 3 3H2O B(OH )3 3H2 Apart from diborane, in highly concentrated solutions it can be used in fuel cell applications. of sulfuric and hydrochloric acids the gas released also In the presence of a cobalt catalyst the sodium + + → + contained+ impurities of sulfur oxides and hydrogen borohydride2NaBH hydrolysis4 6H2 OproceededH2SO at4 a uniformNa 2SO rate4 and2B (OH )3 8H2 (8) chloride, respectively. was completed within 6 minutes (Fig. 2) to produce 83 Sodium borohydride interaction with water in the Ncm3 of the gas.+ In this +case, the→ hydrogen+ sources are+  NaBH 4 3H2O HCl NaCl B(OH )3 4presenceH2 of a cobalt catalyst proceeded at a uniform rate( 9) sodium borohydride and water: and was completed within 6 min. It was demonstrated + → +  that in this case water vapor was the only impurity in the NaBH 4 4H 2O NaB(OH )4 4H 2 (10) (10) released hydrogen allowing the hydrogen it to be supplied to the anode space of a proton exchange membrane fuel At the onset of the reaction the NaBH /Co tablets 4 cell without purification and humidification. Control over dissolved, accompanied by a growth in the reaction rate the hydrogen generation rate is possible by varying the (Fig. 2). After 30 sec the rate of the catalytic interaction cobalt catalyst content in tablets. of hydride with water became constant and was equal to 13.8±0.1 cm3·min-1. The quantity of the hydride remaining Acknowledgements: This work was conducted within in the reaction medium did not influence the process rate, the framework of the budget project No. 0303-2016-0015 indicating that the reaction was zero-order in sodium 1 for Boreskov Institute of Catalysis. The authors are grateful borohydride. Similar behavior of sodium borohydride to Tayban E.S. for providing kinetic experiments. hydrolysis has been observed not only in the presence of a cobalt catalyst [63-66], but also in the presence of ruthenium [67-70], [71-73], platinum [74] and References bimetallic Ni-Co [75], Ni-Ru [76], Co-Mn [77] catalysts. The main reason for the constant rate of reagent conversion [1] Abdalla A.M., Hossain S., Nisfindy O.B., Azad A.T., Dawood M., may be the limited quantity of catalyst in the reaction Azad A.K., Hydrogen production, storage, transportation and key challenges with applications: A review, Energ. Convers. medium. By varying the content of the cobalt catalyst in Manage., 2018, 165, 602-627. the tablets it is possible to set required rates of hydrogen [2] Züttel A., methods, Naturwissenschaften, generation as was demonstrated in [38]. It should be noted 2004, 91, 157-172. that according to IR spectroscopy data (Fig. 3) only water [3] Niaz S., Manzoor T., Pandith A.H., Hydrogen storage: Materials, vapor was present as an impurity in the forming hydrogen methods and perspectives, Renew. Sust. Energ. Rev. 2015, 50, which allowed its use in a proton exchange membrane 457-469. [4] Zacharia R., Rather S.U., Review of solid state hydrogen storage fuel cell without humidification [78]. methods adopting different kinds of novel materials, J. Nanomater., 2015, 2015, 914845. [5] Durbin D.J., Malardier-Jugroot C., Review of hydrogen storage techniques for on board vehicle applications, Int. J. Hydrogen Energy., 2013, 38, 14595-14617.

1 46 O.V. Netskina, et al.

[6] Pukazhselvan D., Kumar V., Singh S.K., High capacity hydrogen [24] Akdim O., Demirci U.B., Miele P., Acetic acid, a relatively green storage: Basic aspects, new developments and milestones, single-use catalyst for hydrogen generation from sodium Nano Energy. 2012, 1, 566-589. borohydride, Int. J. Hydrogen Energy, 2009, 34, 7231-7238. [7] Jiang H.-L., Singh S.K., Yan J.-M., Zhang X.-B., Xu Q., Liquid-Phase [25] Balbay A., Sahin O., Hydrogen production from sodium chemical hydrogen storage: Catalytic hydrogen generation borohydride in water mixtures., Energ. Source Part under ambient conditions, ChemSusChem, 2010, 3, 541-549. A., 2014, 36, 1166-1174. [8] Mohtadi R., Remhof A., Jena P., Complex metal : [26] Balbay A., Saka C., Effect of addition on the

Multifunctional materials for energy storage and conversion, J. hydrogen production from hydrolysis of NaBH4 with Cu based Phys.: Condens. Matter., 28 (2016) 353001. catalyst, Energ. Source Part A., 2018, 40, 794-804. [9] Ley M.B., Jepsen L.H., Lee Y.-S., Cho Y.W., Bellosta Von Colbe J.M., [27] Javed U., Subramanian V.(R.), Hydrogen generation using a Dornheim M., Rokni M., Jensen J.O., Sloth M., et al., Complex borohydride-based semi-continuous milli-scale reactor: Effects hydrides for hydrogen storage - New perspectives, Mater. of physicochemical parameters on hydrogen yield, Energy Today, 2014, 17, 122-128. Fuels, 2009, 23, 408-413. [10] Yadav M., Xu Q., Liquid-phase chemical hydrogen storage [28] Murugesan S., Subramanian V.(R.), Effects of acid accelerators materials, Energy Environ Sci., 2012, 5, 9698-9725. on hydrogen generation from solid sodium borohydride using [11] Chen P., Hydrogen storage: Liquid and chemical, In: A. Sayigh small scale devices, J. Power Sources, 2009, 187, 216-223. (Ed.), Comprehensive Renewable Energy: Fuel Cells and [29] Abdul-Majeed W.S., Arslan M.T., Zimmerman W.B., Application Hydrogen Technology, Elsevier Ltd., Amsterdam, 2012. of acidic accelerator for production of pure hydrogen from

[12] Li H.-W., Yan Y., Orimo S.-I., Züttel A., Jensen C.M., Recent NaBH4, Int. J. Ind. Chem., 2014, 5, 15. progress in metal borohydrides for hydrogen storage, [30] Minkina V.G., Shabunya S.I., Kalinin V.I., Martynenko Energies., 2011, 4, 185-214. V.V., Stability of aqueous-alkaline sodium borohydride [13] Jain I.P., Jain P., Jain A., Novel hydrogen storage materials: A formulations, Russ. J. Appl. Chem., 2008, 81, 380-385. review of lightweight complex hydrides, J. Alloys Compd., 2010, [31] Minkina V.G., Shabunya S.I., Kalinin V.I., Martynenko V.V., 503, 303-339. Smirnova A.L., Stability of Alkaline Aqueous Solutions of [14] Kong V.C.Y., Foulkes F.R., Kirk D.W., Hinatsu J.T., Development Sodium Borohydride, Int. J. Hydrogen Energy, 2012, 37, of hydrogen storage for fuel cell generators. I: Hydrogen 3313-3318. generation using hydrolysis hydrides, Int. J. Hydrogen Energy., [32] Netskina O.V., Komova O.V., Mukha S.A., Simagina V.I.,

1999, 24, 665-675. Aqueous-alkaline NaBH4 solutions: The influence of hydride

[15] Fakioglu E., Yurum Y., Veziroglu T.N., A review of hydrogen decomposition on catalytic properties of Co3O4, Catal. storage systems based on boron and its, Int. J. Hydrogen Commun., 2016, 85, 9-12. Energy., 2004, 29, 1371-1376. [33] Netskina O.V., Komova O.V., Simagina V.I., Odegova G.V.,

[16] Akkuş M.S., Murathan H.B., Özgür D.Ö., Özkan G., Özkan G., Prosvirin I.P., Bulavchenko O.A., Aqueous-alkaline NaBH4 New insights on the mechanism of vapour phase hydrolysis solution: The influence of storage duration of solutions on of sodium borohydride in a fed-batch reactor, Int. J. Hydrogen reduction and activity of cobalt catalysts, Renewable Energy, Energy., 2018, 43, 10734-10740. 2016, 99, 1073-1081. [17] Demirci U.B., Akdim O., Andrieux J., Hannauer J., Chamoun [34] Liu B.H., Li Z.P., Suda S., Solid sodium borohydride as a R., Miele P., Sodium borohydride hydrolysis as hydrogen hydrogen source for fuel cells, J. Alloys Compd., 2009, 468, generator: Issues, state of the art and applicability upstream 493-498. from a fuel cell, Fuel Cells., 2010, 10, 335-350. [35] Liu C.-H., Kuo Y.-C., Chen B.-H., Hsueh C.-L., Hwang K.-J., Ku

[18] Liu B.H., Li Z.P., A review: Hydrogen generation from J.-R., Tsau F., Jeng M.-S., Synthesis of solid-state NaBH4/ borohydride hydrolysis reaction, J. Power Sources, 2009, 187, Co-based catalyst composite for hydrogen storage through 527-534. a high-energy ball-milling, Int. J. Hydrogen Energy, 2010, 35,

[19] Demirci U.B., Miele P., Cobalt in NaBH4 hydrolysis, Phys. Chem. 4027-4040. Chem. Phys., 2010, 12, 14651-14665. [36] Netskina O.V., Ozerova A.M., Komova O.V., Odegova G.V., [20] Zhong H., Ouyang L.Z., Ye J.S., Liu J.W., Wang H., Yao X.D., Simagina V.I., Hydrogen storage systems based on solid-state

Zhu M., An one-step approach towards hydrogen production NaBH4/CoxB composite: Influence of catalyst properties on

and storage through regeneration of NaBH4, Energy Storage hydrogen generation rate, Catal. Today, 2015, 245, 86–92. Materials, 2017, 7, 222-228. [37] Netskina O.V., Komova O.V., Prosvirin I.P., Pochtar’ A.A., [21] Manna J., Roy B., Sharma P., Efficient hydrogen generation Ozerova A.M., Simagina V.I., Solid-State Hydrogen-Generating from sodium borohydride hydrolysis using silica sulfuric acid Composites Based on Sodium Borohydride: Effect of the catalyst, J. Power Sources, 2015, 275, 727-733. Heat Treatment of Boron–Cobalt Catalysts on the Hydrogen [22] Nabid M.R., Bide Y., Fereidouni N., Boron and co-doped Generation Rate, Russ. J. Appl. Chem., 2017, 90, 1666-1673. carbon dots as a metal-free catalyst for hydrogen generation [38] Simagina V.I., Ozerova A.M., Komova O.V., Odegova G.V., from sodium borohydride, New J. Chem., 2016, 40, 8823-8828. Kellerman D.G., Fursenko R.V., Odintsov E.S., Netskina O.V., [23] Kim H.J., Shin K.-J., Kim H.-J., Han M.K., Kim H., Shul Y.-G., catalysts for small-scale energy application, Jung K.T., Hydrogen generation from aqueous acid-catalyzed Catal. Today, 2015, 242, 221-229. hydrolysis of sodium borohydride, Int. J. Hydrogen Energy, [39] Netskina O.V., Ozerova A.M., Komova O.V., Kochubey D.I., 2010, 35, 12239-12245. Kanazhevskiy V.V., Ishchenko A.V., Simagina V.I., The effect of heat-treatment temperature of cobalt-boron catalysts on their Hydrogen generation by both acidic and catalytic hydrolysis of sodium borohydride 47

activity in sodium borohydride hydrolysis, Top. Catal., 2016, [57] Brown H.C., Schlesinger H.I., Sheft I., Ritter D.M., Addition 59, 1431–1437. Compounds of Hydrides. Sodium Trimethoxyboro- [40] Netskina O.V., Kochubey D.I., Prosvirin I.P., Malykhin S.E., hydride and Related Compounds, J. Am. Chem. Soc., 1953, 75, Komova O.V., Kanazhevskiy V.V., Chukalkin Yu.G., Bobrovskii 192–195. V.I., Kellerman D.G., Ishchenko A.V., et al., Cobalt-boron [58] Duke B.J., Gulbert J.R., Read I.A., Preparation and purification of

catalyst for NaBH4 hydrolysis: The state of the active diborane, J. Chem. Soc. A., 1964, 540-542. component forming from cobalt chloride in a reaction medium, [59] Weiss H.G., Shapiro I., Diborane from the sodium borohydride- Mol. Catal., 2017, 441, 100–108. sulfuric acid reaction, J. Am. Chem. Soc., 1959, 81, 6167–6168. [41] NIST Chemistry WebBook: NIST Standard Reference Database, [60] Dunn J.P., Koppula P.R., Stenger H.G., Wachs I.E., Oxidation No 69, 2018. https://webbook.nist.gov/chemistry. of sulfur dioxide to sulfur trioxide over supported vanadia

[42] Devlin J.P., Sadlej J., Buch V., Spectra of Large H2O catalysts, Appl. Catal. B, 1998, 19, 103-117. Clusters: New Understanding of the Elusive Bending Mode of [61] Liu Y.-T., Tsai M.-T., Liu C.-Y., Tsai P.-Y., Lin K.-C., Shih Y.H., Chang Ice, J. Phys. Chem. A, 2001, 105, 974-983. A.H.H., Photodissociation of gaseous acetyl chloride at 248 nm [43] Roscioli J.R., Diken E.G., Johnson M.A., Horvath S., McCoy A.B., by time-resolved fourier-transform : The

Prying Apart a Water with Anionic H-Bonding: A HCl, CO, and CH2 product channels, J. Phys. Chem. A, 2010, 114,

Comparative Spectroscopic Study of the X-·H2O (X = OH, O, F, 7275-7283. Cl, and Br) Binary Complexes in the 600−3800 cm-1 Region, J. [62] Robertson E.G., Medcraft C., Puskar L., Tuckermann R., Phys. Chem. A, 2006, 110, 4943–4952. Thompson C.D., Bauereckerc S., McNaughtona D., IR [44] Brubach J.-B., Mermet A., Filabozzi A., Gerschel A., Roy P., spectroscopy of physical and chemical transformations in cold Signatures of the hydrogen bonding in the infrared bands of hydrogen chloride and ammonia aerosols, Phys. Chem. Chem. water, J. Chem. Phys., 2005, 122, 184509. Phys., 2009, 11, 7853–7860. [45] Brack P., Dann S.E., Upul Wijayantha K.G., Heterogeneous and [63] Zhao J.Z., Ma H., Chen J., Improved hydrogen generation from homogenous catalysts for hydrogen generation by hydrolysis alkaline solution using carbon-supported Co-B as catalysts, Int.

of aqueous sodium borohydride NaBH4 solutions, Energy Sci. J. Hydrogen Energy, 2007, 32, 4711-4716. Eng., 2015, 3, 174-188. [64] Andrieux J., Swierczynski D., Laversenne L., Garron A., [46] Simagina V.I., Komova O.V., Netskina O.V., Nano-sized cobalt Bennici S., Goutaudier C., Miele P., Auroux A., Bonnetot B.,

catalysts for hydrogen storage systems based on ammonia A multifactor study of catalyzed hydrolysis of solid NaBH4 on borane and sodium borohydride, In: A.A. Gromov, U. Teipel cobalt : thermodynamics and kinetics, Int. J. (Eds.), Metal Nanopowders: Production, Characterization, and Hydrogen Energy, 2009, 34, 939-951. Energetic Applications, Wiley-VCH, Verlag, 2014. [65] Rakap M., Ozkar S., Intrazeolite cobalt (0) nanoclusters as [47] Bell R.P., Longuet-Higgins H.C., The normal vibrations of low-cost and reusable catalyst for hydrogen generation from

bridged X2Y6 , Proc. R. Soc. London, A., 1945, 183, the hydrolysis of sodium borohydride, Appl. Catal. B, 2009, 91, 357-374. 21-29. [48] Price W.C., The absorption spectrum of diborane, J. Chem. [66] Zhang X., Zhao J., Cheng F., Liang J., Tao Z., Chen J., Electroless- Phys., 1948, 16, 894-902. deposited Co-P catalysts for hydrogen generation from alkaline

[49] Song Y., Murli C., Liu Z., In situ high-pressure study of diborane NaBH4 solution, Int. J. Hydrogen Energy, 2010, 35, 8363-8369. by infrared spectroscopy, J. Chem. Phys., 2009, 131, 174506. [67] Amendola S.C., Sharp-Goldman S.L., Janjua M.S., Kelly M.T., [50] Davis R.E., Swain C.G., General acid catalysis of the hydrolysis Petillo P.J., Binder M., An ultrasafe hydrogen gas generator: of sodium borohydride, J. Am. Chem. Soc., 1960, 82, aqueous, alkaline borohydride solutions and Ru Catalyst, J. 5949–5950. Power Sources, 2000, 85, 186-189.

[51] Kreevoy M.M., Hutchins J.E.C., H2BH3 as intermediate in [68] Hsueh C.-L., Chen C.-Y., Ku J.-R., Tsai S.-F., Hsu Y.-Y., Tsau F., tetrahydridoborate hydrolysis, J. Am. Chem. Soc., 1972, 94, Jeng M.-S., Simple and fast fabrication of polymer template-Ru 6371-6376. composite as a catalyst for hydrogen generation from alkaline

[52] Olah G.A., Westerman P.W., Mo Y.K., Klopman G., Electrophilic NaBH4 solution, J. Power Sources, 2008, 177, 485-492. reactions at single bonds. VII. Hydrogen-deuterium exchange [69] Liang Y., Dai B.H., Ma L.P., Wang P., Cheng H.M., Hydrogen accompanying protolysis (deuterolysis) of the borohydride generation from sodium borohydride solution using a and aluminum hydride anion with anhydrous strong acids. ruthenium supported on graphite catalyst, Int. J. Hydrogen

The intermediacy of pentahydroboron (BH5) and pentahyd- Energy, 2010, 35, 3023-3028.

roaluminum (AlH5) and their structural relationship with the [70] Ozkar S., Zahmakiran M., Hydrogen generation from hydrolysis + methonium (CH5 ), J. Am. Chem. Soc., 1972, 94, 7859-7862. of sodium borohydride using Ru(0) nanoclusters as catalyst, J. [53] Willen R., Possible mechanisms of the reaction between tetrahy- Alloys Compd., 2005, 404-406, 728-731. droborate and hydrogen ion: A permutational analysis, J. Chem. [71] Hua D., Hanxi Y., Xinping A., Chuansin C., Hydrogen production Soc., Dalton Trans., 1979, 1, 33-40. from catalytic hydrolysis of sodium borohydride solution [54] Davis R.E., Boron hydrides. IV. Concerning the geometry of the using , Int. J. Hydrogen Energy, 2003, 28, activated complex in hydrolysis of borohydride ion by trimethy- 1095-1100. lammonium ion, J. Am. Chem. Soc., 1962, 84, 892-894. [72] Metin O., Ozkar S., Hydrogen generation from the hydrolysis [55] Levine L.A., Kreevoy M.M., Solvent isotope effects on tetrahydri- of sodium borohydride by using water dispersible, hydrogen- doborate hydrolysis, J. Am. Chem. Soc., 1972, 94, 3346-3349. -stabilized nickel (0) nanoclusters as catalyst, Int. J. [56] Schlesinger H.I., Brown H.C., Metallo Borohydrides. III. Hydrogen Energy, 2007, 32, 1707-1715. Borohydride, J. Am. Chem. Soc., 1940, 62, 3429–3435. 48 O.V. Netskina, et al.

[73] Liu B.H., Li Z.P., Suda S., Nickel- and cobalt-based catalysts for hydrogen generation by hydrolysis of borohydride, J. Alloys Compd., 2006, 415, 288-293. [74] Guella G., Patton B., Miotello A., Kinetic features of the platinum catalyzed hydrolysis of sodium borohydride from 11B NMR measurements, J. Phys. Chem. C, 2007, 111, 18744-18750. [75] Ingersoll J.C., Mani N., Thenmozhihal J.C., Muthaiah A., Catalytic hydrolysis of sodium borohydride by a novel nickel-cobalt- boride catalyst, J. Power Sources, 2007, 173, 450-474. [76] Liu C.H., Chen B.H., Hsueh C.L., Ku J.R., Jeng M.S., Tsau F., Hydrogen generation from hydrolysis of sodium borohydride using Ni-Ru nanocomposite as catalysts, Int. J. Hydrogen Energy, 2009, 34, 2153-2163. [77] Mitov M., Rashkov R., Atanassov N., Effects of nickel foam dimensions on catalytic activity of supported Co-Mn-B nanocomposites for hydrogen generation from stabilized borohydride solutions, J. Mater. Sci., 2007, 42, 3367-3372. [78] Vasu G., Tangirala A.K., Viswanathan B., Dhathathreyan K.S., Continous bubble humidification and control of relative

humidity of H2 for a PEMFC system, Int. J. Hydrogen Energy, 2008, 33, 4640-4648.