The preparation and performance of high activity Ni-Cr binary catalysts for direct borohydride fuel cells

Abstract

Ni-Cr binary anode catalysts used in direct borohydride fuel cells (DBFCs) were prepared using a constant potential electrodeposition method. Compared with pure metal Ni catalysts, the electro-oxidation currents of borohydride ions (BH − 4 ) more than doubled when using Ni-Cr binary catalysts under the same conditions. The enhanced activity of the Ni-Cr binary catalysts could be attributed to the change in distribution of BH 4 − ions on the surface of the Ni electrode. This is due to Cr electrodeposits, which allows a greater number of hydrogen atoms to catalyze from each tetrahedron BH -4 ion. The performance of Ni-Cr binary catalysts could also be improved by optimizing the electrodeposition conditions. The results show that Ni-Cr binary catalysts are optimally prepared using an electrodeposition method of 1s with a Cr 3+ concentration of 0.2 mol L −1 and a potential of −0.100 V. ), theoretical conversion efficiencies (91%), non-toxic catalysts, and the convenient transportation of fuel [1]. These devices employ an alkaline solution of sodium borohydride (NaBH 4 ) as fuel and oxygen or hydrogen peroxide as the oxidant. The DBFC converts the chemical energy stored in the borohydride ion (BH − 4 ) directly into electricity by redox processes. DBFCs not only overcome the disadvantages of production, storage and transportation issues related to the use of hydrogen gas, but also eliminate safety concerns regarding the use of hydrogen gas as fuel in traditional fuel cells. However, the degree of the direct electro-oxidation reaction of borohydride ions (BH To take advantage of the various benefits of different catalyst materials and to improve performance, many researchers have been engaged in developing composite anodic materials such as bi-metallic and multi-metallic materials. The activity and stability of bi-metallic catalysts are better than those of mono-metallic catalysts [10]. Considering the high cost of noble metals such as Au, Pt, and Pd, it is worthwhile to investigate non-precious metal catalysts for use as anode catalysts. Among non-precious metals, nickel is considered a promising candidate for the direct electrooxidation of BH − 4 . Improved performance of DBFCs has been achieved by using anode loading Ni-based composite catalysts on nickel foams [11]. In this paper, Ni-Cr binary anode catalysts for DBFCs were prepared using a constant Ni-Cr binary catalysts, borohydride ion, electro-oxidation, fuel cell

Zinc-Cobalt Alloy Deposited on the Titanium Surface as Electrocatalysts for Borohydride Oxidation

“…Development of cost-effective catalysts for borohydride oxidation, e.g., precious-metal -non-precious-metal bimetallic or even multi-metallic systems allows reducing the content of the expensive material. Nowadays, non-precious systems, such as Ni-Cr, 36 Ni/ZnNi/Ni/Cu 37 and CoNiMnB 38 are particularly attractive, however they have yet to be adequately studied.…”

Investigation of stability of gold nanoparticles modified zinc–cobalt coating in an alkaline sodium borohydride solution

“…Complete replacement of the precious metal by a non-precious one in the binary catalyst followed by their supporting on a relevant non-precious substrate with pronounced outstanding properties has been tested. Nowadays, non-precious systems, such as Ni-Cr [37], Ni/ ZnNi/Ni/Cu [38] and CoNiMnB [39], are particularly attractive; however, they have not yet been adequately studied and call for further investiga-tions. Alternative techniques of partial or full replacement of a non-precious metal by the precious one have also been used.…”

Investigation of sodium borohydride and hydrazine oxidation on gold nanoparticles modified zinc–cobalt coating

“…Nowadays, non-precious systems for DBFC, such as Ni-Cr, [36], Ni/ZnNi/Ni/Cu [37] and CoNiMnB [38] are of particular interest; however, they have not been adequately studied yet. The simple galvanic replacement of Zn by Pd or Au in the Ni-Zn coating enabled fabrication of the stable nanostructures of ternary or even quaternary catalysts like Ni/PdNi [39] or Cu/Ni/AuNi [40] with a reduced content of noble metal that seem to be promising ones for the direct borohydride fuel cells.…”