Porous Cobalt Sulfide Selenium Nanorods for Electrochemical Hydrogen Evolution

Abstract

A key process in electrochemical energy technology is hydrogen evolution reaction (HER). However, its electrochemical properties mainly depend on the catalytic activity of the material itself. Therefore, it is important to find efficient electrocatalysts to realize clean hydrogen production. As a typical kind of catalytic materials, transition metal dichalcogenides (TMCs) play important roles in the field of energy catalysis. As a representative of TMCs, cobalt disulfide (CoS 2 ), recently has raised much research interest owing to its abundant reserves, environmental friendliness, and excellent electrochemical stability. Meanwhile, given the fact that doping is one of the effective methods to improve the electrochemical catalytic property, various means of doping have been researched. Here, we report for the first time that porous-like Se–CoS 2- x (or Se:CoS 2- x ) nanorod can be facilely synthesized via a controllable two-step strategy. It is demonstrated that doping Se can greatly improve the catalytic performance of CoS 2 electrode. The electrode can obtain a current density of 10 mA cm –2 at overpotential of only ∼260 mV. And the current changes with the applied bias voltage in an obvious stepped pattern, in the chronopotential (CP) curve of Se–CoS 2- x , indicating its outstanding mass transfer property and mechanical stability.

Iron-Containing Nickel Cobalt Sulfides, Selenides, and Sulfoselenides as Active and Stable Electrocatalysts for the Oxygen Evolution Reaction in an Alkaline Solution

“…Previous reports have demonstrated that incorporating or doping transition metal sulfides, such as nickel cobalt sulfides with iron, induces lattice strain which results in peak broadening [56]. A small shift towards lower angles of the experimental diffractograms of selenium-containing samples versus the simulated diffractograms of the sulfur-only analogues can be ascribed to a larger lattice spacing which is caused by the larger radius of selenium compared to sulfur [57]. A shift in the peak positions between experimental and simulated diffractograms is also obtained if the sample is not properly aligned with the goniometer axis, e.g., by placing too thick a sample on the sample holder in the Bragg-Brentano geometry [58].…”

In situ Pd-doped MoS2 nanosheets as an HER electrocatalyst for enhanced electrocatalytic water splitting

“…Sample Pd-MS5 showed the presence of 5.25 at% of Pd along with 26.16 at% of Mo and 67.59 at% of S. Heteroatom doping also caused the creation of sulfur vacancies (SVs) in the host system. 12,29,30 The created sulfur vacancies in the Pd-doped MoS 2 samples was experimentally conrmed by EDS analysis. A slight decrement of the S element in the Pd-doped MoS 2 samples as compared to pristine MoS 2 was revealed by the element stoichiometry analysis (Table SI2 †).…”