AgPd Alloy Nanoparticles Decorated MoS₂ 2D Nanosheets: Efficient Hydrogen Evolution Catalyst in Wide pH Condition

Abstract

2D nanosheets of different metal chalcogenides have attracted potential interest due to their appealing physical and chemical properties. In this present study we have developed a novel approach for the synthesis of 2D sheets of MoS 2 following a simple hydrothermal method. Using a simple wet-chemical route, surface of 2D sheets of MoS 2 are modified with AgPd alloy nanoparticles following galvanic exchange technique. Electrocatalytic activity towards hydrogen evolution reaction (HER) of MoS 2 , MoS 2 /Ag, and AgPd alloy was checked in a wide range of pH condition. In 0.5 M H 2 SO 4 , bare MoS 2 nanosheets can generate 10 mA/cm 2 current density upon application of only À 0.329 V vs. reversible hydrogen electrode (RHE). After successful decoration of Ag nanoparticle, MoS 2 /Ag shows improved activity compared to bare MoS 2 sheets. MoS 2 /Ag can generate current density 10 mA/cm 2 only by applying À 0.299 V vs. RHE. Further MoS 2 /AgPd-1 can generate 10 mA/cm 2 current density upon application of À 0.229 V vs. RHE. So, from the result it is clear that the successive inclusion of Pd in place of Ag results in higher electrocatalytic activity. Again, MoS 2 /AgPd-2 can generate 10 mA/cm 2 current density upon application of only À 0.215 V vs. RHE. All the metal and alloy nanoparticle decorated MoS 2 show excellent stability in hydrogen evolution reaction. MoS 2 , MoS 2 /AgPd-1 and MoS 2 /AgPd-2 can generate unaltered current density up to 30 h.[a] M.

Nanoporous Silver Telluride for Active Hydrogen Evolution

“…Raman spectra of the nanoporous AgTe were obtained using a laser with an excitation wavelength of 532 nm. Figure d and Figure S6 show that Raman spectra taken for the sample without nanoporous AgTe have Raman shifts at 81, 132, 163, 210, and 267 cm –1 , which correspond to the Raman spectra of WTe 2 and tungsten oxides. , Raman spectra taken at the sample area with nanoporous AgTe have two Raman peaks at 105 and 152 cm –1 , which do not match those of previously reported Ag metal, Ag nanoparticles, and other Ag-related materials (see Table S2), and thus our nanoporous AgTe has two characteristic Raman-active vibration modes. − …”

“…AgTe showed a better HER performance than pristine Ag and Ag-related compounds including Ag 2 S and Ag 2 Se, as shown in Table . This could be explained by the greater robustness of metal tellurides against oxidation compared with other metal chalcogenides. , Further studies are needed to unveil the extraordinary HER performance of AgTe, which may be related to large spin–orbit coupling, large orbital overlaps with adjacent atoms, and its topological nature, which can provide exotic physics and chemistry in many exotic materials. − With a solid understanding of its crystal and electronic band structure and their roles in the HER, our nanoporous AgTe could be an excellent electrocatalyst for the HER with long-term stability.…”

Doping of MoS2 by “Cu” and “V”: An Efficient Strategy for the Enhancement of Hydrogen Evolution Activity

“…Tiny sheets have an edge length of ∼50 nm and a width of ∼10 nm and function as building blocks for the flower balls. FESEM images indicate that the microwave method helps to grow thinner nanosheets of MoS 2 compared to MoS 2 -NS developed from the hydrothermal method. , The morphology has slightly changed due to doping of transition metals like “V” and “Cu” in the MoS 2 host matrix. The high-magnification FESEM image shows that spherical flower balls become smaller after doping with “Cu.” The diameter of the flower balls of Cu-doped MoS 2 is ∼80 nm.…”

“…MoS 2 nanosheets were synthesized following the hydrothermal method reported earlier by our group and named MoS 2 -NS throughout the text.…”

Catalytic Hydrogen Evolution Reaction Enhancement on Vertically Aligned MoS2 by Synergistic Addition of Silver and Palladium

“…Several MoS 2 morphologies have been exploited in an attempt to maximize HER activity including vertically aligned flakes with modified termination, 3D MoS 2 /graphene foams, core‐shell structures with metals, metal oxides, or other TMDs, and defect‐rich basal planes laden with lattice substitutions or decorated with nanoparticles . Specifically, interest has been given towards the formation of composite electrodes, in some cases, composed of MoS 2 and minimal amounts of silver (Ag) and/or palladium (Pd) . The ideal hybrid electrode of Pd/Ag/MoS 2 electrode should consider activity, stability, and cost.…”