Nickel-Doped Silver Sulfide: An Efficient Air-Stable Electrocatalyst for Hydrogen Evolution from Neutral Water

Abstract

A low-cost, platinum-free electrocatalyst for hydrogen (H 2 ) generation via the water splitting reaction holds great promise to meet the demand of clean and sustainable energy sources. Recent studies are mainly concerned with semiconducting materials like sulfides, selenides, and phosphides of different transition metals as electrocatalysts. Doping of the transition metals within the host matrix is a good strategy to improve the electrocatalytic activity of the host material. However, this activity largely depends on the nature of the dopant metal and its host matrix as well. To exploit this idea, here, in the present work, we have synthesized semiconducting Ag 2 S nanoparticles and successfully doped them with different transition metals like Mn, Fe, Co, and Ni to study their electrocatalytic activity for the hydrogen evolution reaction from neutral water (pH = 7). Among the systems doped with these transition metals, the Ni-doped Ag 2 S (Ni–Ag 2 S) system shows a very low overpotential (50 mV) with high catalytic current in neutral water. The trend in electrocatalytic activity of different transition metals has also been explained. The Ni–Ag 2 S system also shows very good stability in ambient atmosphere over a long period of time and suffers no catalytic degradation in the presence of oxygen. Structural characterizations are carried out using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy to establish the phase purity and morphology of the materials.

Crystal Chemistry, Band-Gap Red Shift, and Electrocatalytic Activity of Iron-Doped Gallium Oxide Ceramics

“…While it is trivial to mention that the creation of new catalytic centers in Ga 2 O 3 through Fe is the reason for the electrocatalytic performance, the nonlinear and bell-shaped behavior of catalytic activity points to a more complex enabling mechanism. It is reported that transition-metal doping adjacent to catalytic centers (mostly electronegative elements such as oxygen or sulfur) in electrocatalysts can enhance its activity by lowering the hydrogen adsorption free energy (Δ G H ). − Hence, the lattice inclusion of Fe while doping creates highly catalytic centers and lowers hydrogen adsorption free energy (Δ G H ) by weakening the bonds between Ga and O atoms in the lattice, resulting in a more favorable adsorption of proton and its subsequent reduction to H 2 . However, this still does not explain the modulation of catalytic activity with respect to doping content, as well as the bell-shaped behavior of the activity.…”

Probing the Surface Chemistry of Nanoporous Gold via Electrochemical Characterization and Atom Probe Tomography

“…It is more difficult to discern this trend from the measurements on pure Ag or as-annealed Ag 95 Au 5 alloy due to the interference from the current densities associated with the oxidation of AgSH ads into Ag 2 S ads . There are also reports of enhanced proton and water reduction rates on heterogeneous catalysts composed of noble and/or transition metal sulfides [ 52 , 53 , 54 , 55 , 56 ].…”

Novel Thermal Decomposition Method for the Synthesis of Iron‐doped SnS2 Nanoparticles and Studies on their Peroxidase‐like Activity

“…[1,2] They are useful in various fields such as energy storage, [3] CO 2 reduction, [4] water splitting, [5] photocatalytic degradation of dyes [6] and catalyst for the synthesis of aromatic aldehydes. [7] The optical, magnetic and electrical properties of metal sulfide nanoparticles can be enhanced by doping and the doped metal sulfide nanoparticles are useful for applications in solar cells, [8] bio-imaging, [9] supercapacitors, [10] hydrogen evolution, [11] photocatalytic reduction [12] and bactericides. [13] Sinsermsuksakul et al have synthesized Sb doped SnS thin films using atomic layer deposition and employed the doped thin films as absorber in solar cells.…”