Fe doped NiSe2 nanoarrays to boost electrocatalytic oxygen evolution reaction

Metal–Organic Framework-Derived Fe-Doped Ni3Se4/NiSe2 Heterostructure-Embedded Mesoporous Tubes for Boosting Oxygen Evolution Reaction

“…Precisely, XPS peaks in the Ni 2p XPS spectrum have been observed at the same binding energies, but the intensity of the Ni 2+ peak is significantly attenuated and the Ni 3+ peak intensity has emerged significantly, confirming the electronic state change (Ni 2+ → Ni 3+ ) during OER (Figure c). , Recent research on pure Ni 3 Se 4 /NiSe 2 heterostructures has established that the dominant Ni 3+ state is attributed to the dominating Ni 3 Se 4 phase formation during OER, rather than Ni–OOH . Contrarily, the emerging Ni 3+ peak confirms the existence of a Ni–OOH or Ni–Fe–OOH intermediate state in Fe-doped nickel selenides, which acts as the new catalytic site for OER. − Evidently, the decrease in the Se content on the material’s surface (13.76 atomic % to 5.64%), and the presence of an attenuated metal-Se peak in its Se 3d XPS spectrum with enhanced Se–O peak approved the Ni–Se site conversion into Ni–O (Figure d). This phenomenon was also supported by the increased oxygen content on the surface (14.47 atomic % to 16.35%).…”

“…However, in most of the OER electrocatalysts, the in situ-formed metal-oxide/oxyhydroxide layer promotes the OER process by forming a new interface between the oxidized surface and the internal composition. However, the in situ formed oxyhydroxide layer could not be detected in the XRD investigation of Ni-MOF-Fe-Se-400@NF after OER because of the dominant Ni 3 Se 4 and Ni foam diffraction peaks. ,, On the other hand, a distinct anodic peak was detected for Ni-MOF-Fe-Se-400 in its LSV test (at 1.39 V), confirming the surface oxidation during OER. , Generally, in most Ni/Fe-based catalysts, the Ni metal is acknowledged as the active material that transforms into its oxidized phase (Ni 2+ → Ni 3+/4+ ) during OER, which is responsible for the redox peak prior to water oxidation, and the doped Fe adjusts the electronic structure of Ni via effective synergistic interactions to maintain its composition during long-time operations. − …”

Comparative Study on Hydrogen Evolution Reaction of Various Cobalt-Selenide-Based Electrocatalysts

“…Transition-metal selenides, such as MoSe 2 , WSe 2 , CoSe 2 , and NiSe 2 [18][19][20][21][22], are Pt-free electrocatalysts with high performance for water dissociation, as proved in theoretical and experimental studies. Among these materials, CoSe 2 exhibits a remarkable performance and high stability in various solutions.…”

Three-Dimensional Strawlike MoSe2-Ni(Fe)Se Electrocatalysts for Overall Water Splitting

“…Tian et al synthesized Fe-doped NiSe 2 materials on carbon cloth. The doping of Fe promoted the formation of Ni 3+ and the newly formed NiFe oxide/hydroxide became the new OER active site, which improved the OER performance (overpotential of 257 mV@10 mA cm –2 ) . Trotochaud et al.…”

“…The doping of Fe promoted the formation of Ni 3+ and the newly formed NiFe oxide/hydroxide became the new OER active site, which improved the OER performance (overpotential of 257 mV@10 mA cm −2 ). 33 Trotochaud et al developed a strategy to absorb Fe impurities with bulk Ni(OH) 2 and found that Fe doping increased the conductivity of samples, while Fe doping can induce partial charge transfer, replacing Ni to form Ni 1−x Fe x OOH as new OER active sites. 34 In a word, by doping nickel-based materials with Fe, the original active sites of nickel-based materials can be changed, thereby improving the OER performance of the catalyst.…”