Structure dependent active sites of Ni<sub>x</sub>S<sub>y</sub> as electrocatalysts for hydrogen evolution reaction

Chung, Dong Young; Han, Joung Woo; Lim, Dong‐Hee; Jo, Jun-Ho; Yoo, Sung Jong; Lee, Hyunjoo; Sung, Yung‐Eun

doi:10.1039/c4nr07648f

Cited by 122 publications

(51 citation statements)

References 45 publications

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“…48 In our case, the Tafel slopes of all NiS x -m samples (101-148 mV/dec) implied that the rate determining step was the Volmer step, in which the proton adsorption played a key role. 23 In the case of NiS x -3 sample, the Tafel slope was the lowest, indicating that the proton adsorption was much easier than other NiS x samples. Therefore, it was inferred that the superior HER activity of NiS x -3 sample could originate from the much easier proton adsorption.…”

Section: Electrocatalytic Properties For Hydrogen Generationmentioning

confidence: 95%

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Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni₃S₄ for Hydrogen Evolution Reaction

et al. 2016

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The development of efficient noble-metal-free hydrogen evolution catalysts is quite appealing with the aim of providing cost-competitive hydrogen.Herein, nickel sulfides (NiS x ) with tunable NiS/Ni 3 S 4 molar ratios were synthesized via a simple hydrothermal method. Detailed electrochemical studies under neutral conditions indicated that the electrocatalytic property of NiS x catalysts was determined by the composition. Notably, the NiS x sample with the NiS/Ni 3 S 4 molar ratio of 1.0 exhibited the lowest overpotential and charge-transfer resistance. As analyzed from the Tafel plots, the rate determining step of NiS x catalysts for hydrogen generation was the Volmer step, in which the proton adsorption played a key role.Theoretical calculation revealed that NiS and Ni 3 S 4 exhibited the metallic behaviors with different work functions. Consequently, the NiS x sample with the NiS/Ni 3 S 4 molar ratio of 1.0 owned the most adsorbed protons, which led to the highest electrocatalytic property. Meanwhile, NiS x was demonstrated to be efficient cocatalysts to promote photocatalytic hydrogen generation. NiS x /CdS with the S 4 molar ratio of 1.0 showed the best photocatalytic activity with the apparent quantum efficiency of 56.5% at 420 nm. This result was in good agreement with the electrocatalytic activities of NiS x samples, indicating the intrinsic property for efficient hydrogen generation.

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Section: Electrocatalytic Properties For Hydrogen Generationmentioning

confidence: 95%

“…35 Sung and coworkers found that NiS and Ni 3 S 2 showed an apparent difference in electrocatalytic activity owing to their varied atomic configurations and crystalline structures. 23 Recently, Fu et al…”

Section: Introductionmentioning

confidence: 98%

Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni₃S₄ for Hydrogen Evolution Reaction

et al. 2016

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“…[15][16][17][18][19][20] Among them, transition metal suldes such as molybdic sulde, [21][22][23] nickel sulde, [24][25][26] iron sulde 27 and cobalt sulde 28,29 have attracted considerable interest due to their earth abundance and high electrocatalytic activity. However, the poor conductivities of the transition metal suldes have limited their overall electrocatalytic performance, so they are always considered for loading on conductive substrates to improve the materials' electrical conductivity.…”

Section: Introductionmentioning

confidence: 99%

Co₉S₈@N,P-doped porous carbon electrocatalyst using biomass-derived carbon nanodots as a precursor for overall water splitting in alkaline media

Liu

Zhang

et al. 2017

RSC Adv.

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In this study, we first synthesized Co 9 S 8 @N-doped porous carbon (Co 9 S 8 @NC) using shrimp-shell derived carbon nanodots as a carbon/nitrogen source in the presence of CoSO 4 by a one-step molten-salt calcination method. This was followed by low-temperature phosphorization in the presence of NaH 2 PO 2 , whereby Co 9 S 8 @N,P-doped porous carbon (Co 9 S 8 @NPC) was finally obtained using the Co 9 S 8 @NC as a precursor. The results demonstrated that the molten-salt calcination approach can effectively create a pyrolytic product with a porous structure and improve the material's surface area, which is favourable for electrocatalysis-related mass transport and the exposure of catalytic active sites during electrocatalysis. As an electrocatalyst, Co 9 S 8 @NPC exhibits higher catalytic activity for the hydrogen evolution reaction (HER) than Co 9 S 8 @NC in an alkaline medium. Among all the investigated Co 9 S 8 @NPC catalysts, Co 9 S 8 @NPC-10 (mass ratio of NaH 2 PO 2 to Co 9 S 8 @NC ¼ 10 : 1) displays the best HER activity with an overpotential of 261 mV at 10 mA cm À2 in the alkaline medium. Interestingly, Co 9 S 8 @NPC-10 also displays good catalytic activity for the oxygen evolution reaction (OER) in this study.Owing to its bifunctional catalytic activity towards the HER and OER, the fabricated Co 9 S 8 @NPC-10 was simultaneously used as an anode and cathode material to generate O 2 and H 2 from overall water splitting in the alkaline medium, exhibiting a nearly 100% faradaic yield. This study would be helpful to the design and development of high performance non-precious metal electrocatalysts to be applied in overall water splitting to produce H 2 and O 2 . IntroductionElectrocatalytic water splitting has been widely regarded as a potential renewable and sustainable energy technology to generate H 2 for replacing traditional fossil fuels, and H 2 has a high energy density and an environmentally-friendly combustion product. 1-3 To drive electrocatalytic water splitting to generate H 2 , an active electrocatalyst for the hydrogen evolution reaction (HER) is critically important, which would reduce the overpotential for the HER, thereby making the whole water splitting process more energy efficient. To date, the most efficient HER electrocatalysts are almost exclusively applied in acidic media owing to the rapid reaction rate of H + to H 2 on the catalyst surface, 4-8 however, studies on HER catalysts in alkaline media are relatively rare due to the more complex reaction mechanism of OH À on the catalyst surface and the sluggish kinetics of the counterpart electrode reaction for the oxygen evolution reaction (OER) during electrocatalytic water splitting. 9-11 So far, Pt-based and Ru/Ir-based catalysts have been extensively considered as the most active electrocatalysts for the HER and OER respectively in alkaline media, however, their high costs and source scarcity have limited large-scale production applications.3,7,12-14 Therefore, searching for cheap, earthabundant and efficient electrocatalysts with hi...

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“…4,11,13 For instance, Chung et al experimentally found the superior HER performance of NiS over that of Ni 3 S 2 in alkaline media. 13 Jiang et al successfully synthesized Ni x S y with various phases including NiS, NiS 2 and Ni 3 S 2 by adjusting the amounts of S source, confirming the highest HER activity of Ni 3 S 2 in alkaline media. 11 However, these synthesis procedures are either complicated or energyguzzling.…”

mentioning

confidence: 99%

“…All potentials were calibrated to reversible hydrogen electrode (RHE) according to previous report. 13 All electrochemical data were presented with iR compensation. Figure 1 shows the morphologies of pristine Ni x S y and Ni x S y /rGO composites.…”

mentioning

confidence: 99%

Solvent-mediated crystalline phases of Ni_xS_y anchored on rGO sheets as electrocatalysts for hydrogen evolution application

Shi

et al. 2019

Funct. Mater. Lett.

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A facile, one-pot solvent-mediated hydrothermal process was adopted to prepare nickel sulfide nanoparticles decorated on reduced graphene oxide (Ni x S y /rGO) as electrocatalysts for hydrogen evolution reaction (HER). The designed solvent (ethylene glycol and deionized water) played a decisive role in controlling both crystalline phase and morphology of Ni x S y /rGO composites, leading to pure α-NiS nanoparticles uniformly distributed on rGO sheets under suitable volume ratio of ethylene glycol and deionized water (2:1). The optimized α-NiS/rGO showed prominent HER catalytic performance with a rather small Tafel slope of 93 mV/decade and prominent current density of 10 mA/cm 2 at the overpotential of 177 mV in alkaline environments when compared to pristine α-NiS and NiS 2 /rGO catalysts. The excellent catalytic performance and longterm durability even after 8000 cycles confirmed the potential of α-NiS/rGO composites as efficient electrocatalysts for HER in the alkaline media.

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Structure dependent active sites of Ni_xS_y as electrocatalysts for hydrogen evolution reaction

Cited by 122 publications

References 45 publications

Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni₃S₄ for Hydrogen Evolution Reaction

Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni₃S₄ for Hydrogen Evolution Reaction

Co₉S₈@N,P-doped porous carbon electrocatalyst using biomass-derived carbon nanodots as a precursor for overall water splitting in alkaline media

Solvent-mediated crystalline phases of Ni_xS_y anchored on rGO sheets as electrocatalysts for hydrogen evolution application

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Structure dependent active sites of NixSy as electrocatalysts for hydrogen evolution reaction

Cited by 122 publications

References 45 publications

Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni3S4 for Hydrogen Evolution Reaction

Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni3S4 for Hydrogen Evolution Reaction

Co9S8@N,P-doped porous carbon electrocatalyst using biomass-derived carbon nanodots as a precursor for overall water splitting in alkaline media

Solvent-mediated crystalline phases of NixSy anchored on rGO sheets as electrocatalysts for hydrogen evolution application

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Structure dependent active sites of Ni_xS_y as electrocatalysts for hydrogen evolution reaction

Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni₃S₄ for Hydrogen Evolution Reaction

Composition-Dependent Catalytic Activities of Noble-Metal-Free NiS/Ni₃S₄ for Hydrogen Evolution Reaction

Co₉S₈@N,P-doped porous carbon electrocatalyst using biomass-derived carbon nanodots as a precursor for overall water splitting in alkaline media

Solvent-mediated crystalline phases of Ni_xS_y anchored on rGO sheets as electrocatalysts for hydrogen evolution application