Construction of hollow structure cobalt iron selenide polyhedrons for efficient hydrogen evolution reaction

Abstract

The development of highly active, robust and cost-effective noble metal-free electrocatalysts for hydrogen evolution reaction (HER) in alkaline solution remains a severe challenge. In this work, a hollow structure CoSe 2-FeSe 2 heterojunction electrocatalyst (denoted by "(Co,Fe)Se 2 ") was designed by a simple anion exchange reaction and selenization. Benefiting from the unique hollow structure, the (Co,Fe)Se 2 catalyst accelerates diffusion of electrolyte, besides, the CoSe 2-FeSe 2 heterojunction could provide rapid interfacial charge transportation and more active sites for the HER reaction. The (Co,Fe)Se 2 electrode material exhibits good performance for HER in 1 M KOH electrolyte. It needs an overpotential of 124 mV to obtain a current density of 10 mA cm −2 , and the Tafel slope is 65 mV dec −1. Besides, (Co,Fe)Se 2 has a smaller charge transfer resistance compared with CoSe 2. At the same time, it has relatively large electrochemical active surface area due to the porosity. Most importantly, the (Co,Fe)Se 2 electrode displays good stability in alkaline conditions for 15 hours, the linear sweep voltammetry curves are almost coincident before and after 1000 cycles, the overpotential with current density of 10 mA cm −2 increased by only 9.76% after 5000 cycles of CV. It shows great application potential in HER.

Critical Review, Recent Updates on Zeolitic Imidazolate Framework‐67 (ZIF‐67) and Its Derivatives for Electrochemical Water Splitting

“…Xue et al observed that Co Fe mass ratio in (CoFe)Se 2 has a profound effect on its HER activity. [317] In their work, ZIF-67 was used as a self-sacrificial template as well as the source of Co for preparation of CoFe Prussian blue analogs (PBA), which were then transformed into (CoFe)Se 2 hollow structures by direct selenization (Figure 17k,l). The hollow architecture of as prepared polyhedron possessed a high electrochemically active surface area while the synergism among FeSe 2 and CoSe 2 boosted the intrinsic activity of the catalyst.…”

“…Reproduced with permission. [ 317 ] Copyright 2020, John Wiley and Sons. n) Schematic of the synthetic procedure used for the preparation of Co‐VS ex , Co‐VSx, and Co‐VOx.…”

“…m) Bar chart comparing the activity of (CoFe)Se 2 hollow structures with different catalysts. Reproduced with permission [317]. Copyright 2020, John Wiley and Sons.…”

Mechanisms for self‐templating design of micro/nanostructures toward efficient energy storage

“…The Kirkendall effect properly explained the diffusion and exchange reactions between metal cations and sulfide/oxygen anions during the sulfidation/oxidation processes. [68,69] Shen et al synthesized NiCo 2 S 4 hollow nanoparticles with a "ball-in-ball" configuration by using the anion-exchange method. [70] As schematically illustrated in Figure 3C, NiCoglycerate solid nanoparticles were employed as the precursor…”

Core‐shell architecture of NiSe 2 nanoparticles@nitrogen‐doped carbon for hydrogen evolution reaction in acidic and alkaline media

“…Water electrolysis is one of the most promising processes for hydrogen generation and involves the hydrogen evolution reaction (HER). [1][2][3][4][5] However, this process is restricted by the sluggish kinetics of the HER. Therefore, electrocatalysts are typically employed to enhance the HER performance.…”