Charge-Transfer Effects in Fe–Co and Fe–Co–Y Oxides for Electrocatalytic Water Oxidation Reaction

Abstract

Electrocatalytic water splitting is a feasible method to store solar, wind, and water energy in the form of hydrogen fuel. However, the sluggish oxygen evolution reaction (OER) limits the energy efficiency. It is urgent to develop high-efficiency and cost-effective OER catalysts with ample active sites and excellent durability. Herein, we adopted a facile sol–gel method to synthesize a ternary amorphous iron–cobalt–yttrium oxide. The introduction of yttrium to the iron–cobalt composite oxide can improve the dispersion of iron and cobalt to provide more active sites for OER. In addition, the addition of yttrium significantly improves the charge transfer ability of iron–cobalt–yttrium oxide and enhances the OER performance with a low overpotential of 241, 263, and 214 mV at 10 mA cm–2 on a glassy carbon electrode, Pt electrode, and Ni foam, respectively.

One-step pyrolysis for the preparation of sulfur-doped biochar loaded with iron nanoparticles as an effective peroxymonosulfate activator for RhB degradation

“…The Fe 2p high-resolution spectrum revealed that the iron was in the states of Fe 0 2p 3/2 (57.11%), Fe 2+ 2p 3/2 (31.28%), and Fe 3+ 2p 3/2 (11.61%) judging by the positions and intensities of the corresponding 2p 3/2 peaks at 708.5, 709.8 and 711.4 eV, respectively (Fig. 3b), [38][39][40] which was in accordance with previous HR-TEM and XRD results. They coexisted in the Fe/S 0.05 -BC to form mixed valence ferrite nanoparticles.…”

Binary Transition Metal NiFeOx and CoFeOx Cocatalysts Boost the Photodriven Water Oxidation over Fe2TiO5 Nanoparticles

“…XPS spectra of Fe 2 TiO 5 (Figure S4) and the modified catalysts (Figure 3) indicated the effective incorporation of elements that compose the NiFeO x and CoFeO x cocatalysts and their oxidation states, which are of paramount relevance for the function of the photocatalysts [32,34,38] . Figure 3A displays the high‐resolution spectra at the Fe 2p, Ti 2p and Ni 2p energy regions for the material NiFeO x /FeTO‐S1.…”

“…Experimental and theoretical determinations have demonstrated that Fe sites lead to lower water oxidation overpotentials than Ni sites in Ni−Fe oxide/(oxy)hydroxide catalysts. Similar determinations were useful to show that overpotentials for water oxidation with CoO x or Co(OH) 2 can be reduced by the incorporation of Fe into the lattice [26,27,32–35] …”

“…We expect that the cocatalysts synergistically complement the photocatalytic properties of pseudobrookite Fe 2 TiO 5 by incorporating the benefits of the Fe sites-induced optimum electronic properties that result in lower overpotentials and increased activities. [24,32,34,40] Furthermore, most photoanodes present their highest performance in alkaline solutions, where NiFeOOH-and CoFeOOH-type electrocatalysts are stable. [40] Nonetheless, highly efficient photocatalysts are only attained under controlled cocatalyst deposition.…”

Enhancing the Electrocatalytic Activity and Stability of Prussian Blue Analogues Through the Introduction of Au Nanoparticles in a Core@shell Heterostructure

“…Furthermore, our electrocatalysts still display room for improvement since the electrochemical activity can be further improved by using other supporting electrodes (such as Ni foam) and by subjecting the heterostructures to different thermal and physical pretreatments (such as plasma activation). Au@NiO NiO 90 [48] Au@CoFeOx CoFeOx 39 [48] CNTs-Au@Co3O4 CNTs@Co3O4 50 [49] Au/NiFe-LDH NiFe-LDH 30 [50] Ag+Co(OH)2 Co(OH)2 30 [51] Ag@Co(OH)2 Co(OH)2 100 [51] FeNi-rGO FeNi 30 [52] NiO-NiFe2O4/rGO NiO-NiFe2O4 75 [53] Co(OH)2/SWNT Co(OH)2 40 [54] Ni-Fe-Y-Ox -Ni foam Ni-Fe-Y-Ox -GC 27 [55]…”