Synergistic effect of nanosheet-array-like NiFe-LDH and reduced graphene oxide modified Ni foam for greatly enhanced oxygen evolution reaction and hydrogen evolution reaction

Abstract

We have prepared highly efficient bifunctional electrocatalytic composites, NixFe1-LDH/rGO/NF (x = 3, 2, 1), with vertically staggered NiFe-LDH nanosheets grown on Ni foam uniformly modified with reduced graphene oxide through hydrothermal method.

Enhanced Electrocatalytic Activity of Mo-Doped NiFe Layered Double Hydroxide Nanosheet Arrays for the Hydrogen Evolution Reaction

“…The BE value offset of Ni 6 Fe 1 Mo 1 -LDH/NF was the largest in the series catalysts. In the Fe 2p spectrum, two spin–orbital peaks at 712.07 and 725.5 eV are related to Fe 2p 3/2 and Fe 2p 1/2 , respectively, indicating the presence of Fe 3+ . , Moreover, the BE values of the Ni x Fe 1 Mo 1 -LDH/NF ( x = 4, 6, 8, 10) catalysts at Fe 2p 3/2 are 712.12, 712.45, 712.24, and 712.18 eV, respectively, which are 0.05, 0.38, 0.17, and 0.11 eV higher than that of Ni 2 Fe 1 -LDH/NF (712.07 eV), respectively. The Fe 2p 3/2 BE values of the series catalysts have a positive shift compared with Ni 2 Fe 1 -LDH/NF, demonstrating that Mo doping can reduce the electron density of Fe 3+ species.…”

“…To enhance the conductivity of the electrocatalyst and further improve its electrocatalytic activity, the optimum proportion of the catalyst was directly grown on rGO/NF for the first time, and the Ni 6 Fe 1 Mo 1 -LDH/rGO/NF electrocatalyst was obtained. Additionally, a detailed description of the rGO/NF synthesis method and mechanism has been provided in our previous work. , Figure S6 presents the synthesis strategy schematic and XRD patterns of the Ni 6 Fe 1 Mo 1 -LDH/rGO/NF electrode. Figure S7 shows that bare Ni foam usually has a smooth surface, while rGO was uniformly coated on the NF surface in the rGO/NF sample.…”

“…Additionally, a detailed description of the rGO/NF synthesis method and mechanism has been provided in our previous work. 39,40 Figure S6 presents the synthesis strategy schematic and XRD patterns of the Ni 6 Fe 1 Mo 1 -LDH/rGO/NF electrode. Figure S7 shows that bare Ni foam usually has a smooth surface, while rGO was uniformly coated on the NF surface in the rGO/NF sample.…”

“…Chen et al synthesized Ru-doped NiFe-LDH nanosheets on Ni foam, exhibiting excellent HER performance due to effective reduction of the energy barrier of the Volmer step in alkaline solution, and the overpotential at 10 mA cm –2 was 29 mV. Furthermore, Zhang et al , synthesized CoFe-LDH and NiFe-LDH nanosheet arrays in situ grown on reduced graphene oxide uniformly modified Ni foam (rGO/NF), both of which were highly effective for OER and HER, requiring only 1.65 and 1.62 V at 10 mA cm –2 for overall water splitting, respectively. Their excellent performance can be attributed to the open nanosheet array structure, synergistic coupling between LDH and rGO enhancing electrical conductivity, and in situ growth of LDH on rGO/NF.…”

Multifunctional Na-enriched Ni–Fe/Ni–P plates for highly efficient photo- and electrocatalytic water splitting reactions

“…68 The presence of inverse spinel NiFe 2 O 4 formed along with Fe 2 O 3 , NiO and NaNiO 2 in C700 booted the OER activity. The synergism 69 between Ni 2+ and Fe 3+ ions helped the electron shuttling between the components and the great abundance of metal oxides in C700 by calcination and their synergism further enhanced the OER activity. In addition to synergism, oxygen vacancies in metal oxide crystal lattices also play a crucial role in OER activity of metal oxide-based n-type semiconductor catalysts owing to the presence of e g electrons.…”