Activating lattice oxygen in NiFe-based (oxy)hydroxide for water electrolysis

Abstract

Transition metal oxides or (oxy)hydroxides have been intensively investigated as promising electrocatalysts for energy and environmental applications. Oxygen in the lattice was reported recently to actively participate in surface reactions. Herein, we report a sacrificial template-directed approach to synthesize Mo-doped NiFe (oxy)hydroxide with modulated oxygen activity as an enhanced electrocatalyst towards oxygen evolution reaction (OER). The obtained MoNiFe (oxy)hydroxide displays a high mass activity of 1910 A/gmetal at the overpotential of 300 mV. The combination of density functional theory calculations and advanced spectroscopy techniques suggests that the Mo dopant upshifts the O 2p band and weakens the metal-oxygen bond of NiFe (oxy)hydroxide, facilitating oxygen vacancy formation and shifting the reaction pathway for OER. Our results provide critical insights into the role of lattice oxygen in determining the activity of (oxy)hydroxides and demonstrate tuning oxygen activity as a promising approach for constructing highly active electrocatalysts.

Recycling Solar Cells for Hydrogen Production Coupling Hydrazine Degradation with Entropy-Driven High-Chaos Nickel Molybdenum Phosphorus Sulfide Oxides

“…M–S (161.5 eV) and O–S (168.2 eV) peaks of the S 2p envelope can further verify the incorporation of NiS 2 , MoS 2 , and MoO 3 in NiMoPSO NCAs/NF (Figure e) . The O 1s peak situated at 530.4 eV is consistent with that from MoO 3 , and another higher binding energy peak at 532.2 eV may result from the presence of adsorbed water molecules (Figure f) …”

Doping Mo into NiFe LDH/NiSe Heterostructure to Enhance Oxygen Evolution Activity by Synergistically Facilitating Electronic Modulation and Surface Reconstruction

“…[7] He et al fabricated ultra-thin NiFe (oxy) hydroxides with Mo doping by a sacrificial template-directed approach, and further proposed that Mo doping can upshift the O 2p band in NiFe (oxy) hydroxide, weaken the metal-oxygen bond, facilitate the formation of oxygen defects, and thus change the reaction pathway to achieve excellent intrinsic OER activity. [8] 2À in NiFe nanosheets with 3D hierarchical structure to provide more active sites for hydroxide adsorption and oxidation, which also favors mass and charge transport, and draw electrons to aggrandize the valence of 3d metals in OER. [9] Luo et al designed Mo-doped Ni 3 S 2 /Ni x P y hollow nanorods to optimize the electronic structure with more positively charged Ni sites in Ni 3 S 2 , thus facilitating the adsorption of OH À with low Gibbs free energy.…”

“…He et al. fabricated ultra‐thin NiFe (oxy) hydroxides with Mo doping by a sacrificial template‐directed approach, and further proposed that Mo doping can upshift the O 2p band in NiFe (oxy) hydroxide, weaken the metal‐oxygen bond, facilitate the formation of oxygen defects, and thus change the reaction pathway to achieve excellent intrinsic OER activity [8] . Su et al.…”

High-valence Mo doping for highly promoted water oxidation of NiFe (oxy)hydroxide

“…It is also found that the introduction of Mo through doping positively shis the oxidation potential of b-NiOOH to compared to that of g-NiOOH, which is consistent with previous reports. 35,36…”