A New Class of Zn_1‐xFe_x–Oxyselenide and Zn_1‐xFe_x–LDH Nanostructured Material with Remarkable Bifunctional Oxygen and Hydrogen Evolution Electrocatalytic Activities for Overall Water Splitting

Abstract

The scalable and cost‐effective H2 fuel production via electrolysis demands an efficient earth‐abundant oxygen and hydrogen evolution reaction (OER, and HER, respectively) catalysts. In this work, for the first time, the synthesis of a sheet‐like Zn1‐xFex–oxyselenide and Zn1‐xFex–LDH on Ni‐foam is reported. The hydrothermally synthesized Zn1‐xFex–LDH/Ni‐foam is successfully converted into Zn1‐xFex–oxyselenide/Ni‐foam through an ethylene glycol‐assisted solvothermal method. The anionic regulation of electrocatalysts modulates the electronic properties, and thereby augments the electrocatalytic activities. The as‐prepared Zn1‐xFex–LDH/Ni‐foam shows very low OER and HER overpotentials of 263 mV at a current density of 20 mA cm−2 and 221 mV at 10 mA cm−2, respectively. Interestingly, this OER overpotential is decreased to 256 mV after selenization and the HER overpotential of Zn1‐xFex–oxyselenide/Ni‐foam is decreased from 238 to 202 mV at 10 mA cm−2 after a stability test. Thus, the Zn1‐xFex–oxyselenide/Ni–foam shows superior bifunctional catalytic activities and excellent durability at a very high current density of 50 mA cm−2. More importantly, when the Zn1‐xFex–oxyselenide/Ni‐foam is used as the anode and cathode in an electrolyzer for overall water splitting, Zn1‐xFex–oxyselenide/Ni‐foam(+)ǁZn1‐xFex–oxyselenide/Ni‐foam(‐) shows an appealing potential of 1.62 V at 10 mA cm−2. The anionic doping/substitution methodology is new and serves as an effective strategy to develop highly efficient bifunctional electrocatalysts.

In Situ Reconstructed Zn doped FexNi(1−x)OOH Catalyst for Efficient and Ultrastable Oxygen Evolution Reaction at High Current Densities

“…Next, X-ray photoelectron spectroscopy (XPS) measurements were carried out to reveal effects of Zn modification on Ni/FeOOH@NF. Figure 2b shows the Zn spectrum of Zn-(Ni/FeOOH)@NF, the two prominent spin-orbit peaks are attributed to Zn 0 and Zn 2+ , respectively, [32,33] resulting from NiZn alloy and Zn doped FeOOH. The O 1 s spectra of as-prepared Zn-(Ni/FeOOH)@NF show peaks at 529.2, 531.5, and 533.0 eV, which arises from FeO or NiO, FeOH units, and adsorbed H 2 O, respectively (Figure S9, Supporting Information).…”

Fabrication of Polyoxometalate Anchored Zinc Cobalt Sulfide Nanowires as a Remarkable Bifunctional Electrocatalyst for Overall Water Splitting

“…iv) The direct development of the active substance on nickel substrate confirms the immediate contact of the electroactive substance and substrate, which allows effective charge transfer. [62,63] v) The existence of an excessive amount of high-spin Co 3+ ions in the octahedral sites of the spinel structure of zinc cobalt sulfide can effectively accelerate the catalytic activity of the electrocatalyst for HER and OER, [64,65] the dominancy of Co 3+ in the (revealed by Co 2p XPS spectrum in Figure 3b) POM@ZnCoS NWs is also responsible for the excellent bifunctional OER and HER activity.…”

In situ fabrication of cobalt/nickel sulfides nanohybrid based on various sulfur sources as highly efficient bifunctional electrocatalysts for overall water splitting

“…)-based materials have excellent catalytic performance for HER or OER, the low reserves and high cost limit their large-scale industrial applications. [5][6][7][8][9][10] Fe and Mo) sulfides have been shown to possess intrinsic catalytic activity for OER and/or HER, and attract significant attention due to their natural abundance and diverse structure. [11][12][13][14][15][16][17][18][19][20][21][22][23] Owning to its remarkable metallic property and excellent electrical conductivity, nickel sulfide (Ni 3 S 2 ) as a cost effective OER or HER electrocatalyst for water splitting has been intensively investigated.…”