Amorphous molybdenum sulphide @ nanoporous gold as catalyst for hydrogen evolution reaction in acidic environment

Scaglione, Federico; Xue, Yang; Celegato, Federica; Rizzi, Paola; Battezzati, Livio

doi:10.1007/s10853-018-2490-2

Cited by 18 publications

(15 citation statements)

References 50 publications

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“…The edge sites‐driven hydrogen electroadsorption properties of TMDs have prompted the fabrication of amorphous molybdenum sulfide materials (MoS x ) to minimize exposure of the electrocatalytically inert MoS 2 basal planes for multiple applications . A simple, yet scalable method to fabricate MoS x has been reported by substrate‐insensitive electrodeposition from a [MoS 4 ] 2− precursor, and critical properties in MoS x materials such as film thickness, morphology, Mo:S stoichiometry, as well as incorporation of dopants or nanocomposite formation, have been easily tuned by experimental parameters.…”

Section: Introductionmentioning

confidence: 99%

Benchmarking the Activity, Stability, and Inherent Electrochemistry of Amorphous Molybdenum Sulfide for Hydrogen Production

Escalera‐López

Lou

Rees

2019

Advanced Energy Materials

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can be efficiently produced on demand and in a decentralized manner with (photo) electrochemical methods via the hydrogen evolution reaction (HER). [1][2][3][4] Despite of being the best performing HER catalysts, [5,6] noble metals such as Pt, Ir, and Pd are scarce and consequently hamper the viability of water electrolysis technologies. Hence earth-abundant materials, and notably transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS 2 ), have been extensively investigated as HER electrocatalysts. [7][8][9][10][11] The edge sites-driven hydrogen electroadsorption properties of TMDs [12,13] have prompted the fabrication of amorphous molybdenum sulfide materials (MoS x ) to minimize exposure of the electrocatalytically inert MoS 2 basal planes [14] for multiple applications. [15][16][17][18][19] A simple, yet scalable method to fabricate MoS x has been reported by substrate-insensitive electrodeposition from a [MoS 4 ] 2− precursor, [20,21] and critical properties in MoS x materials such as film thickness, [22] morphology, [23][24][25][26] Mo:S stoichiometry, [27] as well as incorporation of dopants [28][29][30] or nanocomposite formation, [31][32][33][34][35] have been easily tuned by experimental parameters.For long-term electrocatalytic applications, however, HER activity and stability of TMDs are paramount. In crystalline MoS 2 , basal plane activation, [36][37][38][39][40][41][42][43] edge site exposure, [44][45][46][47][48][49][50][51][52][53] and metal doping/incorporation/intercalation [54][55][56][57][58][59][60][61][62][63][64][65][66] are the most employed strategies.In contrast, the [Mo 3 S 13 ] 2− cluster-based polymeric structure of electrodeposited MoS x[67] requires alternative approaches to maximize activity. In addition, the detailed HER mechanism as well as the true catalytically active sites are still under debate. Whilst pioneering studies on ambient pressure X-ray photoelectron spectroscopy (XPS) indicated the MoS 2 edge-like sites formed after MoS 3 phase transformation under in operando conditions responsible for the HER performance, [68] in situ X-ray absorption spectroscopy experiments suggested terminal S 2 2− ligands (S 2 2− terminal ) to be the proton acceptor sites, [69] and more recently in situ Raman spectroscopy indicated these to be the electrochemically cleaved bridging S 2 2− ligands (S 2 2− bridging ). [70] Another study claimed that unsaturated Mo centers formed after cathodic dissolution of S 2 2− terminal to be the true HER Anodically electrodeposited amorphous molybdenum sulfide (AE-MoS x ) has attracted significant attention as a non-noble metal electrocatalyst for its high activity toward the hydrogen evolution reaction (HER). The [Mo 3 S 13 ] 2− polymerbased structure confers a high density of exposed sulfur moieties, widely regarded as the HER active sites. However, their intrinsic complexity conceals full understanding of their exact role in HER catalysis, hampering their full potential for water splitting applications. In this report, a unifying app...

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Section: Introductionmentioning

confidence: 99%

Benchmarking the Activity, Stability, and Inherent Electrochemistry of Amorphous Molybdenum Sulfide for Hydrogen Production

Escalera‐López

Lou

Rees

2019

Advanced Energy Materials

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“…Ligaments present the typical features resulting from de-alloying of an amorphous precursor .i.e. a rough and knobby surface constituted by several grains of nanometer size impinged together (see inset Fig.1a); such a morphology, in particular, has been proved having high electro-catalytic activity, compared with ligaments of similar size but fabricated from a crystalline precursor, thanks to retained atoms of Ag and Pd and under-coordinated sites due to surface kinks and originated by grain boundaries of impinged crystals during de-alloying process [30,31].…”

Section: Resultsmentioning

confidence: 99%

Electrodeposited platinum on de-alloyed nanoporous gold with enhanced electro-catalytic performance

Xue

Scaglione

Rizzi

et al. 2019

Applied Surface Science

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In this work, Pt nanoparticles were electrodeposited through cyclic voltammetry technique on three dimensional nanoporous gold, which was prepared by chemical de-alloying of Au-based metallic glass precursor in the form of ribbon. The electro-catalytic properties of the as-prepared samples were tested through potential cycling towards methanol oxidation in alkaline solution. Current density plots vs scan numbers indicate that the electrodes are active for the electro-oxidation of methanol and the Pt electrodeposited on gold ligaments contributes in increasing catalytic properties. In particular, results indicate that nanoporous gold with 30 cycles Pt electrodeposition exhibits competitive higher activity and longer durability towards methanol electro-oxidation.

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“…In the case of an amorphous precursor, ligaments are made up of many nanocrystals [ 12 ] originated by the germination during the transition from amorphous to crystalline structure [ 13 , 14 ]: When lesser noble atoms of the amorphous alloy are dissolved in the electrolyte, more noble atoms are freed by lateral coordination and move as ad-atoms by surface diffusion forming clusters that grow in dimension with the proceeding of the process until they impinge together forming ligaments. As a result, ligaments obtained from the dealloying of an amorphous precursor are multigrained, with more active sites at the grain boundaries and defects, making them more favorable in electrocatalysis applications [ 15 , 16 , 17 ] and surface-enhanced Raman spectroscopy (SERS) [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Breaking Down SERS Detection Limit: Engineering of a Nanoporous Platform for High Sensing and Technology

2022

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In this study, nanoporous gold (NPG) was synthesized by free corrosion dealloying of an amorphous precursor, Au20Cu48Ag7Pd5Si20 (at. %), in a mixture of nitric and hydrofluoric acid, starting from amorphous melt-spun ribbons. NPG revealed a 3D nanoporous structure composed of pores and multigrain ligaments of an average size of 60 nm. NPG was further anodized in oxalic acid at 8 V vs. Ag/AgCl reference electrode to obtain a bimodal morphology composed of ligaments disrupted in finer features. Both NPG and anodized samples (A-NPG) were found to be mechanically stable to bending and active for surface-enhanced Raman scattering (SERS). SERS activity of samples was investigated using 4,4′-bipyridine as a probe molecule. A detection limit of 10−16 M was found for both samples, but in A-NPG, the signal was strongly enhanced. The extremely high enhancement obtained for A-NPG is attributed both to the small size of ligaments and crystals of which they are made, as well as to the nanometric features resulting from anodization treatment. Such a microstructure showed homogenous SERS response in terms of average enhancement all across the surface, as demonstrated by mapping measurements. Furthermore, NPG and A-NPG were tested as electrodes for electrocatalytic applications, showing good properties. The engineering steps from the amorphous precursor to A-NPG led us to obtain a high-sensing platform, with extremely low detection limit and intrinsic properties, that might significantly contribute to the cutting-edge technology of the future.

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Amorphous molybdenum sulphide @ nanoporous gold as catalyst for hydrogen evolution reaction in acidic environment

Cited by 18 publications

References 50 publications

Benchmarking the Activity, Stability, and Inherent Electrochemistry of Amorphous Molybdenum Sulfide for Hydrogen Production

Benchmarking the Activity, Stability, and Inherent Electrochemistry of Amorphous Molybdenum Sulfide for Hydrogen Production

Electrodeposited platinum on de-alloyed nanoporous gold with enhanced electro-catalytic performance

Breaking Down SERS Detection Limit: Engineering of a Nanoporous Platform for High Sensing and Technology

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