“…In order to overcome these challenges, many effective strategies have been proposed, including modifying the surface and interface, 14,15 architecture engineering, 16,17 improving electronic conductivity, 18,19 etc . Among them, surface and interface engineering has been widely accepted as a promising route to modulate the surface and interface properties of catalysts, which not only boosts the exposure of surface active sites, but also facilitates the charge transfer via heterointerfaces during electrochemical reactions.…”
Rational hybridization of two-dimensional (2D) nanomaterials with extrinsic species has shown great promise for boosting electrocatalytic oxygen evolution reaction (OER). To date, the rational design and engineering of heterojunctions based...
“…In order to overcome these challenges, many effective strategies have been proposed, including modifying the surface and interface, 14,15 architecture engineering, 16,17 improving electronic conductivity, 18,19 etc . Among them, surface and interface engineering has been widely accepted as a promising route to modulate the surface and interface properties of catalysts, which not only boosts the exposure of surface active sites, but also facilitates the charge transfer via heterointerfaces during electrochemical reactions.…”
Rational hybridization of two-dimensional (2D) nanomaterials with extrinsic species has shown great promise for boosting electrocatalytic oxygen evolution reaction (OER). To date, the rational design and engineering of heterojunctions based...
“…Apart from these experimental evidences, related theoretical proof has been also demonstrated by previous reports. ,,,,, For OER reaction, its reaction pathway in alkaline medium is based on the 4e-mechanism put forward by Norskov, as shown in equations (I–IV): (I) * + H 2 O → *OH + H + + e – (Δ G I ); (II) *OH → *O + H + + e – (Δ G II ); (III) *O + H 2 O → *OOH + H + + e – (Δ G III ); and (IV) *OOH → * + O 2 + H + + e – (Δ G IV ). Here, “*” represents the active sites on catalysts, Δ G I , Δ G II , Δ G III , and Δ G IV stand for the reaction Gibbs free energies .…”
Section: Resultsmentioning
confidence: 53%
“…Apart from these experimental evidences, related theoretical proof has been also demonstrated by previous reports. 25,29,30,37,47,48 When ΔG H* = 0 eV, the HER performance is optimal since the proton reduction rate and desorption rate of absorbed H on the surface of electrocatalyst can reach balance. As reported by previous studies, 25,29,30 the introduction of vanadium can significantly reduce the Gibbs free energy of the rate-determining step (RDS) and adsorption energy during OER and HER reaction processes.…”
Section: Electrocatalytic Performance For Hermentioning
This is the first time that the pore-space-partition (PSP) strategy is being successfully applied in the electrochemical field for water splitting, realizing the highly efficient construction of a series of ultrastable pristine MOF electrocatalysts. On integrating the vanadiumbased trimetallic building cluster (M 2 V), the target M 2 V-MOFs exhibit excellent electrocatalytic activity for HER, OER, and water splitting. In particular, ultralow overpotentials of 314 and 198 mV for Fe 2 V-MOF as OER and HER electrocatalysts, respectively, can drive a current density of 10 mA cm −2 . The fabricated Fe 2 V-MOF||Pt/C two-electrode configuration for the overall water splitting yields a current density of 10 mA cm −2 at only 1.6 V vs RHE, which is superior to that of the commercial IrO 2 ||Pt/C couple. Notably, high structural and chemical stabilities still can be observed in alkaline condition. This work opens up an exciting pathway to design efficient and stable electrocatalysts based on pristine MOF by integrating the PSP strategy and multimetallic centers.
“…Furthermore, we operated the XPS spectra (Figure 4f−i) to determine the surface composition and oxidation states of the outer shell material. The fitted peaks of Ni 2p at 855.6 and 873.3 eV can be ascribed to Ni 3+ , 12,51 which indicate the total oxidation of the Ni element during the ISAO process. A large number of high-valence Ni 3+ are favorable to improve the OER activity of the amorphous NiFe hydroxide outer shell.…”
Section: Resultsmentioning
confidence: 93%
“…41,42 The three well-fitted peaks of V 2p for Fe,V-NiSe 2 located at 514.8, 516.1, and 517.1 eV suggest that V contain +3, +4, and +5 oxidation states, respectively. 12,43 These multivalent vanadium cations can enhance the intrinsic conductivity of the Fe,V-NiSe 2 sample. 23 The Se 3d spectra (Figure 3d) are divided into 3d 5/2 (54.2 eV) and 3d 3/2 (55.1 eV) doublets, which reveals the presence of Se 2 2− in various diselenides.…”
Developing
non-noble metal-based core–shell heterojunction
electrocatalysts with high catalytic activity and long-lasting stability
is crucial for the oxygen evolution reaction (OER). Here, we prepared
novel core–shell Fe,V-NiSe2@NiFe(OH)x heterostructured nanoparticles on hydrophilic-treated carbon paper
with high electronic transport and large surface area for accelerating
the oxygen evolution rate via high-temperature selenization
and electrochemical anodic oxidation procedures. Performance testing
shows that Fe,V-NiSe2@NiFe(OH)
x
possesses the highest performance for OER compared to as-prepared
diselenide core-derived heterojunctions, which only require an overpotential
of 243 mV at 10 mA cm–2 and a low Tafel slope of
91.6 mV decade–1 under basic conditions. Furthermore,
X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy
(SEM) confirm the morphology and elementary stabilities of Fe,V-NiSe2@NiFe(OH)
x
after long-term chronopotentiometric
testing. These advantages are largely because of the strong synergistic
effect between the Fe,V-NiSe2 core with high conductivity
and the amorphous NiFe(OH)
x
shell with
enriched defects and vacancies. This study also presents a general
approach to designing and synthesizing more active core–shell
heterojunction electrocatalysts for OER.
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