Hierarchical Co–FeS₂/CoS₂ heterostructures as a superior bifunctional electrocatalyst

Abstract

The traditional method of preparing hydrogen and oxygen as efficient clean energy sources mainly relies on the use of platinum, palladium, and other precious metals. However, the high cost and low abundance limit wide application of such metals. As such, one challenging issue is the development of low-cost and highefficiency electrocatalysts for such purposes. In this study, we synthesized Co-FeS 2 /CoS 2 heterostructures via a hydrothermal method for efficient hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Benefitting from their unique three-dimensional hierarchical nanostructures, Co-doped FeS 2 , and CoS 2 formed heterostructures on Co-FeS 2 petals, which bestowed remarkable electrocatalytic properties upon Co-FeS 2 /CoS 2 nanostructures. Co-FeS 2 /CoS 2 effectively catalyzed the OER with an overpotential of 278 mV at a current density of 10 mA cm À2 in 1 M KOH solution, and also is capable of driving a current density À10 mA cm À2 at an overpotential of À103 mV in 0.5 M H 2 SO 4 solution. The overpotential of the OER and HER only decreased by 5 mV and 3 mV after 1000 cycles. Our Co-FeS 2 / CoS 2 materials may offer a promising alternative to noble metal-based electrocatalysts for water splitting.

Fabrication of C/Co-FeS2/CoS2 with Highly Efficient Hydrogen Evolution Reaction

“…In this study, we used glucose as a carbon source to synthesize carbon doped Co-FeS 2 /CoS 2 (C/Co-FeS 2 /CoS 2 ) on carbon cloth via a one-step hydrothermal method. The resulting electrode shows excellent HER catalytic activity with an overpotential of 88 mV at a current density −10 mA•cm −2 in 0.5 M H 2 SO 4 solution; this is 15 mV lower than the overpotential of our previous research [19]. Because of the incorporation of carbon that results in synergistic catalysis between carbon and Co-aFeS 2 /CoS 2 , the performance of the catalyst is significantly improved due to the improvement in conductivity of C/Co-FeS 2 /CoS 2 and the reduction of resistance between C/Co-FeS 2 /CoS 2 and the substrate [27][28][29][30][31][32].…”

“…The current status of platinum-based and palladium-based electrocatalysis for water splitting exhibits good hydrogen evolution performance; however, the high cost and low earth abundance seriously hinder the large-scale application of precious metal electrocatalysts [1,[12][13][14][15][16][17]. Non-precious metal electrocatalysts received great attention, but the catalytic performance of non-precious metal electrocatalysts is still far from that of noble metal catalysts [18][19][20][21][22][23].…”

Ultrafine Cobalt‐Doped Iron Disulfide Nanoparticles in Ordered Mesoporous Carbon for Efficient Hydrogen Evolution

“…The ultra‐small size and high dispersity of sulfide particles lead to exposure of more active sites, thereby significantly improving the activity of the electrode. Furthermore, the HER activity of Co 0.25 Fe 0.75 S 2 @OMC/CC is obviously superior to most of the reported FeS 2 ‐based catalysts (Table S1), such as FeS 2 −RGO (η 10 =139 mV), Co−FeS 2 /CoS 2 (η 10 =105 mV) and Fe 0.5 Co 0.5 S 2 /KB‐10N (η 10 =150 mV) …”

Hollow Structured Carbon@FeSe Nanocomposite as a Promising Anode Material for Li‐Ion Batteries

“…As shown in Figure S6, the D-band at 1340 cm À 1 and G-band at 1585 cm À 1 are associated with the defective and graphitic carbon, respectively. [28] According to the relative intensity of these deconvoluted peaks, the chemical state of Fe in SÀ C@FeSe and TÀ C@FeSe should mainly be Fe(II). [26] The carbon contents in SÀ C@FeSe and TÀ C@FeSe estimated by TG analyses in air ( Figure S7) are 10 % and 20 %, respectively.…”

“…The other four peaks at 712.0, 725.2, 718.0 and 731.0 eV are ascribed to the Fe2p 1/2 and Fe2p 3/2 spin-orbits of Fe(III) as well as their corresponding satellite peaks. [28] According to the relative intensity of these deconvoluted peaks, the chemical state of Fe in SÀ C@FeSe and TÀ C@FeSe should mainly be Fe(II). The small amount of Fe(III) should come from the partial oxidation of FeSe by oxygen during the sample transfer.…”