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

Abstract

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. Recently, singleatom alloys (SAAs), which comprise separated solute atoms in metallic matrix, show great potential on circumventing scaling relationships. [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. Consequently, constructing Ru-based SAAs opens a new avenue toward high HER performance.Herein, we reported the synthesis of RuAu SAAs through a laser ablation in liquid (LAL) technique, which possesses strong quenching effect so as to fabricate metastable nanostructures with novel properties. [30,31] We choose Au as the alloying element on the basis of the following considerations: First, Au is known as an inert metal with weak hydrogen adsorption thus can counteract the strong hydrogen adsorption of Ru matrix. Second, the immiscibility between Au and Ru may create a unique geometric and electronic structure in RuAu SAAs. [32,33] Finally, chemically inert Au favors long-term durability during the reaction. As such, the as-prepared RuAu catalyst exhibits a low overpotential, 24 mV@10 mA cm −2 , which is much lower than Pt/C (46 mV@10 mA cm −2 ) in alkaline media. Moreover, the turnover frequency (TOF) of RuAu SAAs is three times that of the Pt/C catalyst. Density functional theory (DFT) computation reveals that the high performance originates from the relay catalysis of Ru host (for water dissociation) and Au dopant (for hydrogen evolution). To the best of our knowledge, this is the first report on the synthesis of RuAu SAAs with outstanding HER performance in alkaline media. Furthermore, the idea of the mixing immiscible metallic elements by LAL can be facilely Highly efficient and stable catalysts for the hydrogen evolution reaction, especially in alkaline conditions are crucial for the practical demands of electrochemical water splitting. Here, the synthesis of a novel RuAu single-atom alloy (SAA) by laser ablation in liquid is reported. The SAA exhibits a high stability and a low overpotential, 24 mV@10 mA cm −2 , which is much lower than that of a Pt/C catalyst (46 mV) in alkaline media. Moreover, the turnover frequency of RuAu SAA is th...

Laser‐Ablation‐Produced Cobalt Nickel Phosphate with High‐Valence Nickel Ions as an Active Catalyst for the Oxygen Evolution Reaction

“…However, the OER is very sluggish due to the multi‐step proton‐coupled electron transfer . Two strategies are usually adopted to enhance the OER performance, one is to increase the amount of active sites and the other is to improve the intrinsic activity of catalyst . Specifically, the amount of active sites could be promoted through designing diverse nanostructures, decreasing particles size, and achieving amorphous structures; while the intrinsic activity could be improved by generating high‐valence metal cations via defect engineering (e.g., introducing vacancies) …”

Atomic‐Local Environments of Single‐Atom Catalysts: Synthesis, Electronic Structure, and Activity

“…4) The most common application of SAAs is based on C-H activation, such as PtCu SAAs toward butane hydrogenation, [121] PtNi for hydrogenation from aqueous ammonia-borane, [122] NiCu for ethanol dehydrogenation, [123] and PdCu for phenylacetylene hydrogenation, [27b] which can achieve both effective dissociation of reactants and weak binding of intermediates, leading to high selectivity, stability, and resistance to poisoning. Beyond that, the SAAs can be used in other fields as well, such as electrocatalytic hydrogen evolution, [54,124] photocatalytic conversion, [125] and hydrogen storage. [126] M 1 -Other Supports: Similarly, carbon-vacancy, sulfur-vacancy, titanium-vacancy, and the nitrogen-vacancy in supports, such as MoS 2 , TiC, TiN, and MXene, were also found to show strong interactions with metal ions forming single atom sites.…”

Emerging Metal Single Atoms in Electrocatalysts and Batteries

“…[107] Recently, to fully utilize the atoms of noble metals, downsizing the catalyst nanoparticle to SAs has been highly desirable. [108][109][110][111][112][113][114][115][116][117][118][119][120][121] The ALD technique was used to generate the isolated Pt SAs and clusters, resulting in the utilization of approximately all the Pt atoms. [114] The size and loading density of Pt catalysts can be precisely adjusted by simply changing the number of ALD cycles or the deposition time.…”