Facile Synthesis of Amorphous Ternary Metal Borides–Reduced Graphene Oxide Hybrid with Superior Oxygen Evolution Activity

Abstract

Metal borides represent an emerging family of advanced electrocatalyst for oxygen evolution reaction (OER). Herein, we present a fast and simple method of synthesizing iron-doped amorphous nickel boride on reduced graphene oxide (rGO) sheets. The hybrid exhibits outstanding OER performance and stability in prolonged OER operation. In 1.0 M KOH, only 230 mV is required to afford a current density of 15 mA cm −2 with a small Tafel slope of 50 mV dec −1 . DFT calculations lead to a suggestion that the in situ formation of MO x H y during electrochemical activation acts as active sites for water oxidation. The superior OER activity of the as-prepared catalyst is attributed to (i) its unique amorphous structure to allow abundant active sites, (ii) synergistic effect of constituents, and (iii) strong coupling of active material and highly conductive rGO. This work not only provides new perspectives to design a highly effective material for OER but also opens a promising avenue to tailor the electrochemical properties of metal borides, which could be extended to other materials for energy storage and conversion technologies.

Nanostructured core–shell metal borides–oxides as highly efficient electrocatalysts for photoelectrochemical water oxidation

“…15 Only recently, metal boride catalysts have shown excellent electrochemical catalytic performances due to their fast kinetics and superior stability, stemming from the synergistic effect of in situ formed thin oxide, hydroxide or oxyhydroxide layer and boride core. 3,16,17 A Ni-B@NiO x H catalyst supported on nickel foam showed for instance 20 mA cm −2 at 0.28 V overpotential in 1.0 M KOH, which surpassed the activity of most previously reported nonprecious electrocatalysts for OER. 18 Within the core-shell catalysts, the surface shell functions as catalytic sites while the inner core facilitates charge transfer.…”

“…1 Among the potential candidates, hydrogen has emerged to be one of the most promising energy carriers possessing superiorities such as high energy density and abundancy. 2,3 PEC water splitting is considered as a sustainable solution to directly produce hydrogen from water using solar fuel. 4,5 To date, significant improvement has been achieved for photocathodes; profiting highly from the experiences in industrial semiconductor production technology such as solar cell development.…”

“…Conventionally, nanostructured metal boride catalysts are synthesized by the chemical reduction of metal salt precursors with NaBH 4 . 3,22 An additional annealing treatment is usually necessary if crystalline structures need to be obtained. 16 From the practical application perspective for this kind of catalysts, more simple, cost-efficient, high-yield synthetic routes are preferred, for amenable mass production while enabling sufficient active sites.…”

Natural‐Cellulose‐Nanofibril‐Tailored NiFe Nanoparticles for Efficient Oxygen Evolution Reaction

“…[15] Graphene, a typical nanocarbon support, has been widely concerned in energy storage and conversion because of its high porosity and good conductivity. [16,17] For instance, Han et al synthesized Co 1-x Ni x S 2graphene composite, and the CNS-NGA (Ni-doped CoS 2 integrated with nitrogen-doped reduced graphene) showed a much lower overpotential (330 mV at 10 mA cm À 2 ) than CNS (Ni-doped CoS 2 ), which benefited from the three-dimensional (3D) porous structure with a large surface area. [18] However, for graphene-based catalyst, since the number of active groups is limited, the bonding of the metal catalysts with graphene is weak, which prevented the metal catalyst from dispersing homogeneously, and give the resulted electrocatalyst poor stability.…”

“…When it comes to the porous nanostructure, various nanocarbon materials doped with sulfur, nitride, phosphide, boride, and oxide have been investigated as a metal support to improve the catalytic performance . Graphene, a typical nanocarbon support, has been widely concerned in energy storage and conversion because of its high porosity and good conductivity . For instance, Han et al synthesized Co 1‐x Ni x S 2 ‐graphene composite, and the CNS‐NGA (Ni‐doped CoS 2 integrated with nitrogen‐doped reduced graphene) showed a much lower overpotential (330 mV at 10 mA cm −2 ) than CNS (Ni‐doped CoS 2 ), which benefited from the three‐dimensional (3D) porous structure with a large surface area .…”