Synthesis of Ni/NiO@MoO_3−x Composite Nanoarrays for High Current Density Hydrogen Evolution Reaction

Abstract

High current density hydrogen evolution reaction (HER) in alkaline water electrolysis plays crucial role in renewable and sustainable energy systems, while posing a great challenge to the highly‐efficient electrocatalysts. Here, the synthesis of Ni/NiO@MoO3−x composite nanoarrays is reported by a moderate reduction strategy, combining Ni/NiO nanoparticles (≈20 nm) with amorphous MoO3−x nanoarrays. The Ni/NiO@MoO3−x composite nanoarrays possess enhanced hydrophilicity, optimize reaction energy barriers, accelerate reactant diffusion/bubble detachment, and therefore display an ultrahigh alkaline HER activity with a low η10 overpotential of 7 mV as well as Tafel slope of 34 mV dec−1. More significantly, the Ni/NiO@MoO3−x nanoarrays only demand low overpotentials of 75 and 112 mV to deliver 100 and 200 mA cm−2 hydrogen production current, and can steadily work at 100 mA cm−2 for 40 h, which is more efficient and stable than the Pt/C catalyst.

One-Step Electrochemical Synthesis and Surface Reconstruction of NiCoP as an Electrocatalyst for Bifunctional Water Splitting

“…Transition-metal-based electrocatalysts have shown great potential for overall water splitting over the past few years. Various oxides (MoO x ) [ 9 ], hydroxides (Ni(OH) 2 ) [ 10 , 11 ], sulfides (MoS 2 ) [ 12 ], selenides (MoSe 2 ) [ 13 ], nitrides (VN) [ 14 ], and carbides (MXene) [ 15 , 16 ] materials have been extensively reported as water splitting electrocatalysts. Among the aforementioned catalysts, transition metal phosphides (TMPs) possess a hydrogenase-like structure, and are regarded as promising nonprecious electrocatalysts for overall water splitting [ 17 , 18 , 19 , 20 , 21 , 22 ].…”

Boosting Hydrogen Oxidation Kinetics by Promoting Interfacial Water Adsorption on d-p Hybridized Ru Catalysts

“…Moreover, the increased water adsorption on Sn-Ru/C was demonstrated by the test of the contact angle (CA). As depicted in Figure b, the Sn-Ru/C and Ru/C show different hydrophilicities with water CAs of 145.8 and 132.0°, respectively, suggesting that Sn-Ru/C is much easier to contact with water than Ru/C . Water adsorption on the catalyst surface was also detected by Raman spectroscopic technology.…”

Construction of core–shell Ni–Co(OH)F@NiCo2S4nanorods for highly efficient hydrazine-assisted hydrogen evolution

“…The final adsorption capacities of Ni–Co(OH)F, Co(OH)F@CoS 2 , Ni–Co(OH)F@NiCo 2 S 4 and NiCo 2 S 4 for H 2 were 4.0, 2.7, 0.98 and 0.54 mmol mg −1 , respectively. 11 The corresponding electrochemical curves further indicated that Ni–Co(OH)F has the most positive hydrogen adsorption peak with 0.438 V compared to NiCo 2 S 4 with 0.212 V, Ni–Co(OH)F@NiCo 2 S 4 with 0.242 V and Co(OH)F@CoS 2 with 0.333 V. As a more positive peak suggested the stronger adsorption for H species, 40 it can be summarized that the order of hydrogen adsorption ability was Ni–Co(OH)F > Co(OH)F@CoS 2 > Ni–Co(OH)F@NiCo 2 S 4 > NiCo 2 S 4 , which agrees well with the H 2 pulse chemical adsorption test results. In addition, the Ni 0 species appeared in the XPS spectrum of Ni–Co(OH)F@NiCo 2 S 4 core–shell nanorods possessing relatively weak adsorption for H species.…”

“…In addition, the Ni 0 species appeared in the XPS spectrum of Ni–Co(OH)F@NiCo 2 S 4 core–shell nanorods possessing relatively weak adsorption for H species. 33,40 This may adjust the strong H adsorption behavior of Co in the Ni–Co(OH)F@NiCo 2 S 4 catalyst. 8,12,42 Therefore, the Ni–Co(OH)F@NiCo 2 S 4 core–shell nanorods show a moderate H adsorption behavior.…”