In Situ Anodic Oxidation Tuning of NiFeV Diselenide to the Core–Shell Heterojunction for Boosting Oxygen Evolution

Abstract

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.

Enhancing Water Oxidation of Ru Single Atoms via Oxygen-Coordination Bonding with NiFe Layered Double Hydroxide

“…Note here that the oxidation states of nickel and iron for pure NiFe LDH are +2 and +3, respectively. In the Ni 2p and Fe 2p spectra of the SA Ru/NiFe LDH sample, the characteristic peaks of Ni 2p 3/2 and Fe 2p 3/2 are located in 855.81 and 711.80 eV, which are ascribed to Ni 2+ and Fe 3+ , respectively. , Compared with pure NiFe LDH material, there are slightly negative shifts of 0.13 and 0.22 eV in Ni and Fe of SA Ru/NiFe LDH, respectively, demonstrating the electron transfer from Ru to Ni and Fe via the Ru–O–M (M = Ni or Fe) bond. This indicates that Ru SAs in the SA Ru/NiFe LDH catalyst results in the electron rearrangement of NiFe LDH and optimization of their electronic structure, enhancing the catalytic activity of NiFe LDH.…”

“…Note here that the oxidation states of nickel and iron for pure NiFe LDH are +2 and +3, respectively. In the Ni 2p and Fe 2p spectra of the SA Ru/NiFe LDH sample, the characteristic peaks of Ni 2p 3/2 and Fe 2p 3/2 are located in 855.81 and 711.80 eV, which are ascribed to Ni 2+ and Fe 3+ , respectively 38,40. Compared with pure NiFe LDH material, there are slightly…”

“…In the Ni 2p and Fe 2p spectra of the SA Ru/NiFe LDH sample, the characteristic peaks of Ni 2p 3/2 and Fe 2p 3/2 are located in 855.81 and 711.80 eV, which are ascribed to Ni 2+ and Fe 3+ , respectively. 38,40 Compared with pure NiFe LDH material, there are slightly 2c) are split into 3p 3/2 at 461.97 eV and 3p 1/2 at 485.14 eV doublets. 36 The binding energy of Ru 3p 3/2 is slightly higher than that of 461.70 eV (Ru 0 3p 3/2 ) but lower than that of 462.19 eV (Ru II 3p 3/2 ).…”

“…Furthermore, the O 1s spectra of SA Ru/NiFe LDH (Figure2d) displays two signals at 529.88 and 531.15 eV, assigning to Ru−O lattice bonds and surface hydroxyl groups (M−OH, M = Ni or Fe), respectively 36,35. Compared with pure NiFe LDH, a slight negative shift (0.08 eV) is found in the O 1s spectra of SA Ru/ NiFe LDH, suggesting the formation of a Ru−O bond due to the electronic interaction between Ru SAs and NiFe LDH 40,36. The peak fitting of C 1s in two samples (FigureS4b) indicates that the signals at 284.6, 285.79, and 288.69 eV corresponds to C−C, O−C−O, and O�C�O, respectively, 18 illustrating the presence of carbonate ions in the interlamination of two LDH materials.…”

Iron and Hafnium Co-Doped Ni3 N Nanostructures as An Active Catalyst for Alkaline Water Oxidation

“…This result agrees with the diffraction peaks at 78.5, 58.8, and 42.4° in the XRD pattern of Fe, Hf-Ni 3 N sample. The HAADF-STEM and corresponding maps (Figure 1e-j 2a), the Ni 2p 3/2 peaks at 854.95 eV and 851.86 eV in Fe, Hf-Ni 3 N samples can be attributed to Ni 2+ feature, which undergo a slightly negative shift compared to Ni 3 N [14][15][16]. This could be due to electrons transfer from Fe and Hf to Ni, which will accelerate the OER rate [17].…”