An electrochemical method for direct hydrogen production from boron compounds

Abstract

The present disclosure relates to an electrochemical method that comprises the direct production of hydrogen from boron compound types by reduction-oxidation reactions, the simultaneous production of boron hydride compounds and the production of hydrogen by oxidation-reduction reactions of boron hydride compounds, which does not require any additional pH adjustment or purification procedure in a solution system containing low-cost boron compounds (boric acid, boron salts, etc.), and which provides direct production of high purity hydrogen in a single step and at room temperature in an environmentally friendly and low-cost manner.

Description

[0001] AN ELECTROCHEMICAL METHOD FOR DIRECT HYDROGEN PRODUCTION FROM BORON COMPOUNDS

[0002] Technical Field

[0003] The present disclosure relates to an electrochemical method that does not require any additional pH adjustment or purification procedure, is environmentally friendly, and enables the production of high purity hydrogen with low-cost, in a single step and at room temperature in a solution system containing low-cost boron compounds (boric acid, boron salts, etc.).

[0004] State of the Art

[0005] Considering the increasing energy demand, the depletion of fossil fuel resources, as well as the alarming increase in climate change and environmental pollution, the high demand for clean, sustainable and renewable alternative energy sources is increasing day by day. Hydrogen, which is considered a key priority in achieving current goals among advanced energy technologies, is known as a clean, environmentally friendly, economically alternative and sustainable energy source [1 ,2], When all these reasons are taken into consideration, the idea that hydrogen will take the lead in the world energy market in the future and lead to economic growth brings the necessity of its production and effective use to the forefront. However, obtaining, storing and transporting the pure form of hydrogen is a difficult and complex process [3]. In addition, the use of existing hydrogen sources and hydrogen production with traditional methods are insufficient for applications requiring high energy demand (the desired energy density cannot be achieved due to the small storage area of mobile systems) [4,5]. The boron element has a strategically important place in hydrogen production and storage due to its chemical hydrides and nanostructured forms [3,6].

[0006] Among the boron compounds, sodium borohydride (NaBHD), discovered by Schlesinger and Brown in 1940 and known as the most important of the commercial boron hydrides, is a very strategic material in terms of having important advantages such as being hydrogen-rich, stable, very light and environmentally friendly [7,8]. Hydrogen produced from the hydrolysis of sodium borohydride is used for niche energy applications such as fuel cell power systems, internal combustion engines, unmanned aerial vehicles and portable mobile power devices, etc. [7-9], In addition, direct borohydride fuel cells (DBFCs), in which it is used as fuel, have come to the fore in recent years due to their significant advantages such as low operating temperature, flammability, crossover problem, high energy density and cell voltage [1 ,10,11]. Considering these superior properties, NaBHD, which allows hydrogen production by hydrolysis under ambient conditions, is an ideal hydrolytic compound with a promising future in terms of both the wide range of applications and commercialisation potential. However, it currently bears some important difficulties that need to be resolved. The self-hydrolysis reaction of sodium borohydride occurs exothermically. However, its reaction efficiency under ambient conditions is only around 7-8%, which is quite low [12,13]. From the catalytic hydrolysis of sodium borohydride, highly purified HD gas is obtained without any harmful side gas products based on the following reactions

[0014] , However, the hydrolysis reaction for hydrogen production from sodium borohydride is not reversible and it is important that the HDO / BHD' ratio is higher than 4:1 for high efficiency of hydrolysis. In addition, the reaction product sodium metaborate exists in different hydration degrees or forms depending on the solution pH and temperature

[0015] .

[0007] NaBHD shows high stability in alkaline aqueous solution and is usually kept stable in solutions with sodium hydroxide (NaOH) to prevent and control the spontaneous hydrolysis problem. To this end, there is a need for the use of suitable catalysts to facilitate the complete hydrolysis of NaBHD in an alkaline solution environment and to increase its reaction efficiency. The hydrolysis of sodium borohydride is carried out with the help of metal-containing or non-metallic catalysts. In this direction, in the patent application numbered 2019 / 05675, which is one of the studies in the state of the art, it is mentioned that the desired amount of hydrogen cannot be obtained in the catalysts prepared with known methods and the methods in which these catalysts are used and that the catalysts deteriorate in a short time. It is explained that a cobalt-based catalyst was developed as a solution to this problem. The use of catalysts in hydrolysis processes brings with it many disadvantages such as high cost, low electrocatalytic activity, low efficiency, high temperature, low stability, unsustainable source and the need to apply multiple process steps [16-19]. In addition, when sodium borohydride is considered in terms of direct use as a hydrogen source in fuel cells, its oxidation by electrochemical methods is among the current topics of the literature. According to the equation given below, NaBHD is oxidised to sodium metaborate (NaBOD) as a result of its electrochemical reaction with NaOH in aqueous medium, releasing 6 moles of water (HDO) and 8 moles of e- [20,21],

[0008] BI B i - 4.24 V

[0009] In the current electrochemical methods used in the literature, the oxidation efficiency of sodium borohydride requires control of important parameters such as the concentration of the analyte solution, the selection of the appropriate electrode for the electrolyte solution, temperature, scanning rate and pH. Moreover, in the oxidation reaction of boron hydride, due to problems such as the structure of the electrocatalyst and the low stability in long-term use, as well as the operating conditions, the theoretical high efficiency cannot be fully achieved in practice [22-24], Therefore, the oxidation of boron hydride with the existing electrochemical methods used in the literature requires a complex and stepwise process

[0025] , However, the high cost of NaBHD and the inefficiency of recycling the hydrolysis by-product limit its widespread use

[0026] , For this purpose, the regeneration (recycling from sodium metaborate) and reuse of sodium borohydride, which is produced at high cost, are also important in terms of sustainability. Sodium borohydride regeneration, which includes an irreversible reaction step, can be carried out thermochemically, mechanochemically and electrochemically depending on the energy source used.

[0010] Using thermochemical methods to effectively regenerate NaBHD requires high pressure, temperature and multiple reaction steps [27,28], Mechanochemical methods are like thermochemical processes and the source of energy used is based on mechanical forces [29,30], In electrochemical methods, sodium borohydride can be produced by reducing borates in alkaline solution with the help of suitable catalysts using electrical energy [31 ,32], Regeneration of sodium borohydride or its regeneration from sodium metaborate can theoretically be achieved by direct electrochemical reduction. However, this reduction process in the cathodic region is quite difficult and comprises multiple process steps [33,34], This reduction process requires not only a suitable electrolyte component but also an additional electrolysis step and expensive electrode components

[0035] , Moreover, this process does not constitute a reversible and efficient reaction step in practice and is also insufficient in terms of sustainability

[0036] . Considering all these, the oxidation, regeneration and sustainability of borohydride are of great importance in terms of hydrogen production.

[0011] As a result, there is a need to develop a method that provides direct hydrogen production from boron compounds and sustainable and continuous hydrogen production from boron hydride compounds by electrochemical methods. Direct, single-step electrochemical hydrolysis of boron hydride in aqueous solution and its difficult regeneration are open to development. In this context, the production of hydrogen with industrially scalable, high purity, low cost and environmentally friendly methods for the production, hydrolysis and regeneration of boron hydride in the literature descriptions mentioned above is a very critical issue when evaluated in terms of eliminating the deficiencies in the currently used methods. Since the production of hydrogen from boron compounds comprises many process steps in addition to the high cost and long-term processes, the necessity of producing high purity hydrogen in a single step, on-site and at room temperature with novel, easy, low-cost and environmentally friendly methods is clearly seen and explained with the subject of the invention.

[0012] Brief Description of The Invention

[0013] The present invention relates to an electrochemical method for direct hydrogen production from boron compounds that meets the above-mentioned requirements, eliminates disadvantages and provides some additional advantages.

[0014] The main aim of the invention is to provide an electrochemical method to produce high purity hydrogen in a solution system containing low-cost boron compounds (boric acid, boron salts, etc.) in a single step and at room temperature, which does not require any additional pH adjustment or purification procedure and is environmentally friendly and low-cost.

[0015] By mentioned electrochemical method, unlike the literature, the synthesis of high purity boron hydrides, hydrogen production by oxidation-reduction reactions and regeneration of boron hydrides (reproduction of boron hydride from the formed metaborates) are enabled using cheap carbon-based electrodes directly from sustainable boron compounds in a single step and at room temperature. Another important advantage of mentioned method is that it does not require the use of any catalyst. The production is carried out with the use of 100% domestic and national materials. It offers the opportunity of direct production in a solution environment containing boron compounds by using low-cost carbon-based materials with sustainable resources.

[0016] Mentioned method is low-cost, and since production is carried out in an atmospheric environment at room temperature, it does not require high temperature, pressure and additional heating / cooling systems. Direct production is carried out in a single step and in a single container.

[0017] Mentioned method enables boron hydride regeneration (production of boron hydride from borates) carried out under difficult and costly conditions in a single step and simultaneously at low cost and in a sustainable manner.

[0018] The present disclosure eliminates the boron hydride pretreatment step used in hydrogen production and requires high production costs. Thus, it enables the direct production of high purity hydrogen from low-cost boron compounds.

[0019] In state of the art, the catalyst type, pH, concentration, temperature and scanning rate significantly affect the electrochemical oxidation of the NaBH4compound and complex or limit the system. However, by means of said electrochemical method, these effects are eliminated, and hydrogen production can be carried out directly.

[0020] The production of NaBH4by known electrochemical methods requires high costs and poses an economic obstacle when considered in terms of hydrogen production. Said electrochemical method comes to the forefront economically and strategically in terms of enabling the simultaneous production of boron hydride compounds during the direct production of hydrogen from abundant and low-cost boron compounds. Said electrochemical method does not comprise any pre-treatment step, purification procedure, use of an additional catalyst or the need to prepare a special electrode. In short, by means of said method, the high-cost NaBH4pre-reaction step is eliminated before its use in hydrogen production. Said method is a user-friendly and low-cost production method and does not require complex reaction systems.

[0021] In prior art, the electrochemical reduction process for the regeneration of sodium borohydride from sodium metaborate requires a very difficult process and cost. The aim of the invention in this direction is to provide the direct and easy implementation of the NaBH4regeneration process at low cost as an alternative to the methods used in the literature and to added-value to the innovation of the subject of the invention. Another aim of the invention is to provide an electrochemical method that does not use harmful chemicals to the environment and human health. In the invention, which describes an easy, cheap, fast, user- and environment-friendly electrochemical hydrogen production method, no waste is released into the environment during production.

[0022] Turkey is in an important position in economic and strategic terms as the country with the largest boron reserves in the world. When the production and use of hydrogen from boron compounds are considered in terms of economic facts, our production process that is the subject of the invention aims to reduce our country's investment costs in high value-added technologies to even lower levels.

[0023] In addition, it is aimed to provide important solutions to the problems observed in existing technologies for portable and mobile applications in hydrogen fuel technologies by realising the use of the invention in direct liquid-fed boron fuel cells.

[0024] The invention aims to use hydrogen gas produced directly from boron compounds in hydrogen-fuelled automobiles, aircraft, rockets, mobile devices, and similar systems.

[0025] By the method that is the subject of the present disclosure, production of new generation borohydride compounds with high added-value and, by ensuring the continuity of their regeneration, hydrogen production from boron compounds suitable for use in unmanned aerial vehicles, small portable power devices, space rockets, energy storage systems, fuel cells, power devices, various chemical reactions (requiring the use of boron hydride and hydrogen), hydrogenation of foods, etc. is realised.

[0026] By mentioned method, the production of boron hydrides also takes place in the intermediate step during the production of hydrogen gas. It is envisaged that the production and regeneration of boron hydride compounds, which require difficult and expensive processes, will be more widely used in the industry by means of the easy and low-cost synthesis and transformation (repeated use) of the invention.

[0027] The structural and characteristic features of the invention and all its advantages will be understood more clearly by means of the detailed explanation written, and therefore the evaluation should be made by taking this detailed explanation into consideration. Detailed Description of the Invention

[0028] In this detailed description, preferred embodiments of an electrochemical method for direct hydrogen production from boron compounds are explained only for the purpose of better understanding the subject and in a way that does not create any limiting effects.

[0029] The electrochemical method that is the subject of the invention, provides direct high purity hydrogen production in a single step and at room temperature in a solution system containing low-cost boron compounds (boric acid, boron salts, etc.), does not require any additional pH adjustment or purification procedure, and is environmentally friendly and low- cost, comprises the process steps of:

[0030] • preparation of an electrolyte solution system containing boron as acid (boric acid etc.), base or salt form in the concentration range of 0.000001 mol / L-5.0 mol / L,

[0031] • preparation of a three-electrode system, o preparation of a three-electrode system in which the working electrode is carbon-based materials, the counter electrode is carbon-based materials or Pt wire, and the reference electrode is a silver or metal-based electrode containing the solution electrolyte, o connection of the electrodes immersed in the prepared electrolyte system to the current / potential (potentiostat / galvanostat) source by connection cables,

[0032] • direct production of hydrogen by reduction-oxidation reactions from boron species and simultaneously, production of boron hydride compounds and production of hydrogen by oxidation-reduction reactions of boron hydride compounds_,in an electrolyte solution containing boron, without any additional pH adjustment and catalyst requirement in the electrolyte solution, by applying the cyclic voltammetry method directly in high purity, in a single step and at room temperature (ensuring continuity, reducing by-products such as sodium metaborate formed as a result of oxidation of the obtained boron hydrides and converting them back into boron hydrides).

[0033]

[0034] Diagram 1. Schematic representation of hydrogen production by electrochemical method in solution system containing boron compounds

[0035] In all electrochemical production in the method of the present disclosure, there is a current / potential source (potentiostat / galvanostat) device to apply and measure potential or current in a controlled manner.

[0036] Production by the electrochemical method of the present disclosure is carried out using three-electrode or two-electrode systems. Production by the electrochemical method is carried out by connecting the electrodes immersed in the electrolyte to the current / potential (potentiostat / galvanostat) source by connection cables.

[0037] In the potential-controlled electrochemical method of the present disclosure (cyclic voltammetry (CV), production is carried out by applying a potential that changes at certain intervals.

[0038] While the potential that changes at certain intervals with the potentiostat is applied, the potential on the working electrode is controlled by means of the reference electrode and the potentials applied on the working electrode and the counter electrode are recorded by means of the computer.

[0039] In the three-electrode electrochemical method within the method of the present disclosure, carbon-based materials are used as working electrodes, carbon-based materials or Pt wire as counter electrodes, and silver or metal-based electrodes containing solution electrolyte as reference electrodes. In the cyclic voltammetry method, a potential scan was performed at a number of 1 -1000 cycles varying between -6.0 V and +4.0 V at a scanning rate of 1 .0 mV / s and 1 .0 V / s.

[0040] The electrochemical solution system consists of an electrolyte system containing boron in the concentration range of 0.000001 mol / L - 5.0 mol / L.

[0041] The subject of the present disclosure describes an electrochemical method to produce new generation hydrogen in a single step, at room temperature and with high purity, without the need for any additional pH adjustment and catalyst in an electrolyte solution system containing boron compounds (boric acid, boron salts, etc.). With said electrochemical method, in addition to the simultaneous and continuous production of hydrogen in a solution environment containing boron species, the formation of boron hydride compounds, hydrogen production by oxidation-reduction reactions, recycling of sodium metaborate by-product species formed as a result of oxidation of boron hydrides and continuity of their transformation / cycle back to boron hydrides are simultaneously provided.

[0042] In the electrochemical method used for hydrogen production, parameters such as the type of carbon-based material used, the type and concentration of boron source used, the potential operating range, the scanning rate, etc. can be easily adjusted and the appropriate design opportunity can be made according to the scaling. Thus, said electrochemical method also stands out in terms of enabling sustainable hydrogen production at the desired speed and capacity in a controlled manner in a single step at room temperature. The sustainable electrochemical method, which allows the production of high purity hydrogen from abundant and cheap boron compounds and the repeated use of its source, emphasises the innovation of the subject of the invention in terms of not being among the existing methods used in the literature. Our invention, which comprises the production of high purity direct hydrogen at room temperature, in a single step, on-site, with controllable and adjustable production quantities with an environmentally friendly and low-cost electrochemical method, aims to eliminate the problems in existing production methods and increase hydrogen production efficiency. In addition, by means of this invention, the need for complex reaction systems and catalysts that require high costs will be eliminated, and hydrogen production will be possible with the green synthesis method.

[0043] Mentioned electrochemical method covers the direct production of hydrogen from boron compounds in a single step, and comprises the production of boron hydrides, oxidationreduction, and the continuity of hydrogen production simultaneously. By mentioned electrochemical method, direct hydrogen production from boron compounds is carried out in a single step and on-site at room temperature.

[0044] By mentioned electrochemical method, hydrogen production is carried out with carbon-based materials directly from boron compounds and without the use of any catalyst.

[0045] A comparison of the different features and advantages of said method compared to existing methods is presented in detail in Table 1 . Table 1. Comparison of the invention with the prior art

[0046]

[0047] REFERENCES

[0048] [1] H.N. Abdelhamid, A review on hydrogen generation from the hydrolysis of sodium borohydride, Int J Hydrogen Energy. 46 (2021 ) 726-765. https: / / doi.Org / 10.1016 / j . ijhydene.2020.09.186.

[0049] [2] E.A. Vorms, E.A. Suprun, A. v Nartova, R.L Kvon, G. Oshchepkov, Electrochimica Acta Electrodeposited NiCu nanoparticles for the borohydride oxidation reaction : Effect of Cu on the activity and stability of Ni upon surface oxidation, Electrochim Acta. 433 (2022) 141196. https: / / doi.Org / 10.1016 / j. electacta.2022.141196.

[0050] [3] E. Fakioglu, Y. Yurum, T.N. Veziroglu, A review of hydrogen storage systems based on boron and its compounds, Int J Hydrogen Energy. 29 (2004) 1371-1376. https: / / d0i.0rg / l 0.1016 / j. ijhydene.2003.12.010.

[0051] [4] A.G. Olabi, A. saleh bahri, A.A. Abdelghafar, A. Baroutaji, E.T. Sayed, A.H. Alami, H. Rezk, M.A. Abdelkareem, Large-vscale hydrogen production and storage technologies: Current status and future directions, Int J Hydrogen Energy. 46 (2021 ) 23498-23528. https: / / doi.Org / 10.1016 / j.ijhydene.2020.10.110.

[0052] [5] LA. Hassan, H.S. Ramadan, M.A. Saleh, D. Hissel, Hydrogen storage technologies for stationary and mobile applications: Review, analysis and perspectives, Renewable and Sustainable Energy Reviews. 149 (2021 ). https: / / doi.Org / 10.1016 / j.rser.2021.111311.

[0053] [6] Z. Huang, S. Wang, R.D. Dewhurst, N. v. Ignat’ev, M. Finze, H. Braunschweig, Boron: Its Role in Energy-Related Processes and Applications, Angewandte Chemie - International Edition. 59 (2020) 8800-8816. https: / / doi.org / 10.1002 / anie.201911108. [7] H.N. Abdelhamid, A review on hydrogen generation from the hydrolysis of sodium borohydride, Int J Hydrogen Energy. 46 (2021 ) 726-765. https: / / doi.Org / 10.1016 / j . ijhydene.2020.09.186.

[0054] [8] D.M.F. Santos, C.A.C. Sequeira, Sodium borohydride as a fuel for the future,

[0055] Renewable and Sustainable Energy Reviews. 15 (2011 ) 3980-4001. https: / / doi.Org / 10.1016 / j . rser.2011 .07.018.

[0056] [9] U.B. Demirci, O. Akdim, J. Andrieux, J. Hannauer, R. Chamoun, P. Miele, Sodium borohydride hydrolysis as hydrogen generator: Issues, state of the art and applicability upstream froma fuel cell, Fuel Cells. 10 (2010) 335-350. https: / / doi.Org / 10.1002 / fuce.200800171 .

[0057]

[0010] D. Xu, Y. Zhang, Q. Guo, Research progress on catalysts for hydrogen generation through sodium borohydride alcoholysis, Int J Hydrogen Energy. 47 (2022) 5929-5946. https: / / d0i.0rg / l 0.1016 / j . ijhydene.2021 .11 .232.

[0058]

[0011] N.A.M. Harun, N. Shaari, A review on sulfonated poly (ether ether ketone) based-membrane in direct borohydride fuel cell applications , Int J Energy Res. (2022). https: / / doi.Org / 10.1002 / er.8470.

[0059]

[0012] E. Shafirovich, V. Diakov, A. Varma, Combustion-assisted hydrolysis of sodium borohydride for hydrogen generation, Int J Hydrogen Energy. 32 (2007) 207-211. https: / / doi.Org / 10.1016 / j. ijhydene.2006.08.020.

[0060]

[0013] Y. Kojima, Y. Kawai, H. Nakanishi, S. Matsumoto, Compressed hydrogen generation using chemical hydride, J Power Sources. 135 (2004) 36—41. https: / / doi.Org / 10.1016 / j.jpowsour.2004.03.079.

[0061]

[0014] H. Zhang, G. Xu, L. Zhang, W. Wang, W. Miao, K. Chen, L. Cheng, Y. Li, S. Han,

[0062] Ultrafine cobalt nanoparticles supported on carbon nanospheres for hydrolysis of sodium borohydride, Renew Energy. 162 (2020) 345-354. https: / / d0i.0rg / l 0.1016 / j. renene.2020.08.031 .

[0063]

[0015] E.Y. Marrero-Alfonso, A.M. Beaird, T.A. Davis, M.A. Matthews, Hydrogen generation from chemical hydrides, Ind Eng Chem Res. 48 (2009) 3703-3712. https: / / doi.Org / 10.1021 / ie8016225.

[0064]

[0016] B. Jaleh, M. Nasrollahzadeh, A. Nasri, M. Eslamipanah, A. Moradi, Z. Nezafat, Biopolymer-derived (nano)catalysts for hydrogen evolution via hydrolysis of hydrides and electrochemical and photocatalytic techniques: A review, Int J Biol Macromol. 182 (2021 ) 1056-1090. https: / / doi.Org / 10.1016 / j.ijbiomac.2021 .04.087.

[0065]

[0017] H.N. Abdelhamid, A review on hydrogen generation from the hydrolysis of sodium borohydride, Int J Hydrogen Energy. 46 (2021 ) 726-765. https: / / doi.Org / 10.1016 / j. ijhydene.2020.09.186.

[0018] L. Yi, W. Wei, C. Zhao, C. Yang, L. Tian, J. Liu, X. Wang, Electrochemical oxidation of sodium borohydride on carbon supported Pt-Zn nanoparticle bimetallic catalyst and its implications to direct borohydride-hydrogen peroxide fuel cell, Electrochim Acta. 158 (2015) 209-218. https: / / doi.Org / 10.1016 / j.electacta.2O15.01 .111.

[0066]

[0019] S. Kaya, Y. Yilmaz, O.F. Er, D. Alpaslan, B. Ulas, T.E. Dudu, H. Kivrak, Highly Active RuPd Bimetallic Catalysts for Sodium Borohydride Electrooxidation and Hydrolysis, J Electron Mater. 51 (2022) 403-411. https: / / doi.org / 10.1007 / s11664-021 -09306-8.

[0067]

[0020] M. Simoes, S. Baranton, C. Coutanceau, Electrooxidation of sodium borohydride at Pd, Au, and Pd xLAu1 -x carbon-supported nanocatalysts, Journal of Physical Chemistry C. 113 (2009) 13369-13376. https: / / doi.org / 10.1021 / jp902741z.

[0068]

[0021] A. Caglar, T.A. Hansu, O. Sahin, H. Kivrak, The characterization and sodium borohydride electrooxidation of novel carbon nanotube supported copromoted Pd as anode catalyst for fuel cell, Energy Storage. 4 (2022). https: / / doi.org / 10.1002 / est2.301.

[0069]

[0022] C. Shu, T. Sun, J. Jia, Z. Lou, Mild process for reductive desulfurization of diesel fuel using sodium borohydride in situ generated via sodium metaborate electroreduction, Ind Eng Chem Res. 52 (2013) 7660-7667. https: / / doi.org / 10.1021 / ie401073c.

[0070]

[0023] C. Shu, T. Sun, J. Jia, Z. Lou, A novel desulfurization process of gasoline via sodium metaborate electroreduction with pulse voltage using a boron-doped diamond thin film electrode, Fuel. 113 (2013) 187-195. https: / / doi.Org / 10.1016 / j.fuel.2013.05.069.

[0071]

[0024] D.M.F. Santos, C.A.C. Sequeira, On the electrosynthesis of sodium borohydride, in:

[0072] Int J Hydrogen Energy, 2010: pp. 9851-9861. https: / / d0i.0rg / l 0.1016 / j . ijhydene.2010.01 .129.

[0073]

[0025] J. I. Martins, M.C. Nunes, R. Koch, L. Martins, M. Bazzaoui, Electrochemical oxidation of borohydride on platinum electrodes: The influence of thiourea in direct fuel cells, Electrochim Acta. 52 (2007) 6443-6449. https: / / doi.Org / 10.1016 / j.electacta.2007.04.066.

[0074]

[0026] Y. Liu, M. Paskevicius, T.D. Humphries, C.E. Buckley, Simultaneous preparation of sodium borohydride and ammonia gas by ball milling, Int J Hydrogen Energy. 47 (2022) 25347-25356. https: / / doi.Org / 10.1016 / j.ijhydene.2022.05.262.

[0075]

[0027] K. Eom, E. Cho, M. Kim, S. Oh, S.W. Nam, H. Kwon, Thermochemical production of sodium borohydride from sodium metaborate in a scaled-up reactor, Int J Hydrogen Energy. 38 (2013) 2804-2809. https: / / doi.Org / 10.1016 / j.ijhydene.2012.12.053.

[0076]

[0028] T. Ou, M. Panizza, A. Barbucci, Thermochemical recycling of hydrolyzed NaBH4. Part II: Systematical study of parameters dependencies, Int J Hydrogen Energy. 38 (2013) 15940-15945. https: / / doi.Org / 10.1016 / j. ijhydene.2013.09.061 .

[0077]

[0029] C. Lang, Y. Jia, J. Liu, H. Wang, L. Ouyang, M. Zhu, X. Yao, NaBH4 regeneration from NaBO2 by high-energy ball milling and its plausible mechanism, Int J Hydrogen Energy. 42 (2017) 13127-13135. https: / / doi.Org / 10.1016 / j.ijhydene.2017.04.014.

[0030] C. Qakanyildirim, M. Guru, The production of nabh4 from its elements by mechanochemical reaction and usage in hydrogen recycle, Energy Sources, Part A: Recovery, Utilization and Environmental Effects. 33 (2011 ) 1912-1920. https: / / doi.Org / 10.1080 / 15567030903503175.

[0078]

[0031] C. Shu, F. Lai, F. Zhu, D. Luo, Optimal extractive and reductive desulfurization process using sodium borohydride in situ generated via sodium metaborate electroreduction in ionic liquid, Chemical Engineering and Processing - Process Intensification. 150 (2020). https: / / doi.Org / 10.1016 / j.cep.2020.107869.

[0079]

[0032] S. Zhang, B. Chen, L. Gao, T. Xiong, C. Du, Y. Zhu, J. Zhao, Electrochemical reduction of NaBO2 into NaBH4 with pulse voltage using the Eu-Co-Ni-B coating electrode, J Dispers Sci Technol. 43 (2022) 178-187. https: / / doi.Org / 10.1080 / 01932691 .2020.1845957.

[0080]

[0033] H.X. Nunes, D.L. Silva, C.M. Rangel, A.M.F.R. Pinto, Rehydrogenation of sodium borates to close the NaBH4-H2 cycle: A review, Energies (Basel). 14 (2021 ). https: / / doi.Org / 10.3390 / en14123567.

[0081]

[0034] Q. Qakanyildirim, M. Guru, Hydrogen cycle with sodium borohydride, Int J Hydrogen Energy. 33 (2008) 4634-4639. https: / / doi.Org / 10.1016 / j.ijhydene.2008.05.084.

[0082]

[0035] S. Zhang, B. Chen, L. Gao, T. Xiong, C. Du, Y. Zhu, J. Zhao, Electrochemical reduction of NaBO2 into NaBH4 with pulse voltage using the Eu-Co-Ni-B coating electrode, J Dispers Sci Technol. 43 (2022) 178-187. https: / / doi.Org / 10.1080 / 01932691 .2020.1845957.

[0083]

[0036] C. Shu, T. Sun, J. Jia, Z. Lou, A novel desulfurization process of gasoline via sodium metaborate electroreduction with pulse voltage using a boron-doped diamond thin film electrode, Fuel. 113 (2013) 187-195. https: / / doi.Org / 10.1016 / j.fuel.2013.05.069.

[0084]

[0037] Z.P. Li, N. Morigazaki, B.H. Liu, S. Suda, P reparation of sodium borohydride by the reaction of MgH with 2 dehydrated borax through ball milling at room temperature, 2003. www.elsevier.com / locate / jallcom.

[0085]

[0038] D.M.F. Santos, C.A.C. Sequeira, On the electrosynthesis of sodium borohydride, in:

[0086] Int J Hydrogen Energy, 2010: pp. 9851-9861. https: / / d0i.0rg / l 0.1016 / j . ijhydene.2010.01 .129.

[0087]

[0039] L. Yi, W. Wei, C. Zhao, C. Yang, L. Tian, J. Liu, X. Wang, Electrochemical oxidation of sodium borohydride on carbon supported Pt-Zn nanoparticle bimetallic catalyst and its implications to direct borohydride-hydrogen peroxide fuel cell, Electrochim Acta. 158 (2015) 209-218. https: / / d0i.0rg / l 0.1016 / j.electacta.2O15.01 .111.

[0088]

[0040] J. Ma, N.A. Choudhury, Y. Sahai, A comprehensive review of direct borohydride fuel cells, Renewable and Sustainable Energy Reviews. 14 (2010) 183-199. https: / / doi.Org / 10.1016 / j. rser.2009.08.002.

[0041] H. Qelikkan, M. §ahin, M.L. Aksu, T. Nejat Veziroglu, The investigation of the electrooxidation of sodium borohydride on various metal electrodes in aqueous basic solutions, Int J Hydrogen Energy. 32 (2007) 588-593.

Claims

CLAIMS1. An electrochemical method that provides direct high purity hydrogen production in a single step and at room temperature, which is low-cost and environmentally friendly and which is not requiring any additional pH adjustment or purification procedure, in a solution system that containing low-cost boron compounds (boric acid, boron salts, etc.) characterized by comprising the process steps of:• preparation of an electrolyte solution system as boron-containing acid (boric acid, etc.) or base or salt form,• preparation of a three-electrode system, o connection of the electrodes immersed in the prepared electrolyte to the current / potential (potentiostat / galvanostat) source by connection cables,• direct production of hydrogen by reduction-oxidation reactions from boron species in boron containing electrolyte solution by the cyclic voltammetry method in a single step and at room temperature, directly with high purity and without any additional pH adjustment and catalyst requirement in the electrolyte solution while simultaneously production of boron hydride compounds and production of hydrogen by oxidation-reduction reactions of boron hydride.

2. The electrochemical method that provides hydrogen production according to Claim 1 , characterized by comprising; the process step of the preparation of an electrolyte solution system containing boron as acid (boric acid, etc.), base or salt form in the concentration range of 0.000001 mol / L-5.0 mol / L.

3. The electrochemical method that provides hydrogen production according to Claim 1 , wherein; the working electrode is carbon-based materials, the counter electrode is carbon-based materials or Pt wire, and the reference electrode is silver or metalbased electrode containing solution electrolyte.

4. The electrochemical method that provides hydrogen production according to Claim 1 , characterized by comprising; the process step of transformation / conversion again back into boron hydrides by the way of reduction of by-products such as sodium metaborate which is formed as a result of the oxidation of boron hydrides obtained, in the step of obtaining hydrogen by oxidation-reduction reactions of boron hydride compounds for ensuring the continuity.

5. The electrochemical method that provides hydrogen production according to Claim 1 , wherein; the process steps are carried out at room temperature.

6. The electrochemical method that provides hydrogen production according to Claim 1 , characterized by comprising; the process step of applying a variable potential scan in the range of -6.0 V to +4.0 V with a scan rate of 1 -1000 cycles in the range of 1.0 mV / s to 1 .0 V / s.

Images