Ruthenium-cobalt nanoalloys encapsulated in nitrogen-doped graphene as active electrocatalysts for producing hydrogen in alkaline media

Abstract

The scalable production of hydrogen could conveniently be realized by alkaline water electrolysis. Currently, the major challenge confronting hydrogen evolution reaction (HER) is lacking inexpensive alternatives to platinum-based electrocatalysts. Here we report a high-efficient and stable electrocatalyst composed of ruthenium and cobalt bimetallic nanoalloy encapsulated in nitrogen-doped graphene layers. The catalysts display remarkable performance with low overpotentials of only 28 and 218 mV at 10 and 100 mA cm−2, respectively, and excellent stability of 10,000 cycles. Ruthenium is the cheapest platinum-group metal and its amount in the catalyst is only 3.58 wt.%, showing the catalyst high activity at a very competitive price. Density functional theory calculations reveal that the introduction of ruthenium atoms into cobalt core can improve the efficiency of electron transfer from alloy core to graphene shell, beneficial for enhancing carbon–hydrogen bond, thereby lowing ΔGH* of HER.

Electrochemical Flocculation Integrated Hydrogen Evolution Reaction of Fe@N‐Doped Carbon Nanotubes on Iron Foam for Ultralow Voltage Electrolysis in Neutral Media

“…06-0696, cubic, a = 2.8664 Å, b = 2.8664 Å, c = 2.8664 Å). Moreover, the shape and full width at half maximum (FWHM) of the second-order graphitic structure of 2D band indicated that multilayers graphene was existed in the Fe@N-CNT/IF, [10] which was inconsistent with the result in Figure 1g. The weak XRD peaks around 26.6° were detected for carbon with low crystallinity.…”

“…It was clearly shown that only metal Fe phases with the strong diffraction peaks at 44.6° (110), 65.0° (200), and 82.3° (211) were confirmed in Fe@N-CNT/IF (JCPDS No. [10] The high I D /I G band intensity ratio of Fe@N-CNT/IF indicated the generation of large amounts of defects, suggesting that a large amount of N atoms were doped in the graphitic carbon layers. No Fe 2 O 3 phase was detected due to the strong reducing action of carbon derived from the decomposition of dicyandiamide.…”

Channel‐Rich RuCu Nanosheets for pH‐Universal Overall Water Splitting Electrocatalysis

“…[11][12][13][14] Ruthenium, owing to the advantages of the cheapest among platinum group metals and excellent performance in many applications such as N 2 electrochemical reduction and selective hydrogenation, has attracted much attention. [17][18][19][20] Forinstance, Su and co-workers have obtained Cu-doped RuO 2 hollow porous polyhedra through one-step annealing of Ru-exchanged Cu-BTC derivatives,w hich showed remarkable OER performance in 0.5 m H 2 SO 4 . [17][18][19][20] Forinstance, Su and co-workers have obtained Cu-doped RuO 2 hollow porous polyhedra through one-step annealing of Ru-exchanged Cu-BTC derivatives,w hich showed remarkable OER performance in 0.5 m H 2 SO 4 .…”

Ruthenium‐Based Single‐Atom Alloy with High Electrocatalytic Activity for Hydrogen Evolution

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performance and low price for working in alkaline solution.

Ruthenium, as a member of platinumgroup metals with 1/30 price of Pt, [14] has been proved to be a promising catalyst for HER in alkaline solution due to its high efficiency on water dissociation, [15][16][17][18] however, the strong interaction between Ru and H atoms impedes the subsequent hydrogen evolution because of the well-known scaling relationship for heterogeneous catalysts. [17,[19][20][21] Many efforts had been devoted to constructing Rubased heterostructures (e.g., Ru/carbon quantum dots, [22] Ru/C 2 N, [18] RuCo/ nitrogen-doped graphene, [23] fcc-Ru/ C 3 N 4 /C, [17] Ru/nitrogen-doped carbon, [24] Ru/graphene [25] ), which show great advantages on promoting water dissociation by synergistic effect. Nevertheless, less attention was paid on the improvement of hydrogen adsorption.

…”

“…[17,[19][20][21] Many efforts had been devoted to constructing Rubased heterostructures (e.g., Ru/carbon quantum dots, [22] Ru/C 2 N, [18] RuCo/ nitrogen-doped graphene, [23] fcc-Ru/ C 3 N 4 /C, [17] Ru/nitrogen-doped carbon, [24] Ru/graphene [25] ), which show great advantages on promoting water dissociation by synergistic effect. [23,26,27] meanwhile, the interaction between the solute atoms and matrix can modify their electronic structure, [26,28,29] leading to a suitable adsorption energy for hydrogen. Recently, singleatom alloys (SAAs), which comprise separated solute atoms in metallic matrix, show great potential on circumventing scaling relationships.…”