Nickel Foam‐Supported Amorphous FeCo(Mn)−O Nanoclusters with Abundant Oxygen Vacancies through Selective Dealloying for Efficient Electrocatalytic Oxygen Evolution

Abstract

Developing earth‐abundant, cost‐effective and high‐performance electrocatalyst towards the oxygen evolution reaction (OER) is a great challenge for large‐scale hydrogen production from electrochemical water splitting. Nickel‐foam‐supported amorphous hierarchical nanoclusters of metal/metal (hydr)oxides with abundant oxygen defects (FeCo(Mn)−O/NF) were prepared from an FeCoMn/NF precursor through chemical dealloying. The FeCo(Mn)−O/NF electrode exhibits enhanced OER activity in alkaline electrolyte with an overpotential of only 235 mV to drive a current density of 10 mA cm−2, a small Tafel slope of 44.5 mV dec−1 and excellent durability over 100 h. The superior OER performance is attributed to the synergistic effect of abundant oxygen vacancies, hierarchical morphology and amorphous structure, which essentially modulate the electronic structures and create more active sites. These interesting findings highlight the significance of dealloying strategy on the structural defects and improved catalytic performance of the electrocatalysts.

Nanostructuring Nickel–Zinc–Boron/Graphitic Carbon Nitride as the Positive Electrode and BiVO4-Immobilized Nitrogen-Doped Defective Carbon as the Negative Electrode for Asymmetric Capacitors

“…The homogeneity originates from the homogeneous dispersion of g-C 3 N 4 powder and metal precursors in a reaction solution and the ultrafast reduction of metal ions by NaOH and NaBH 4 species. NaBH 4 species avoid phase separation of metals induced by coprecipitation and encourage homogeneous distribution . All of these findings support the formation of multicomponent Ni–Zn–B/g-C 3 N 4 heteronanostructures with tunable morphology and amorphous nature as well as uniform elemental configuration.…”

“…Along with this, the corresponding selected-area electron diffraction (SAED) pattern (Figure S4B, inset) reveals wide and diffused halo rings, certifying that the atomic lattice lacks regular periodicity because of the amorphous characteristic of the product. 32 Figure 3E 33 All of these findings support the formation of S1). As shown in Figure 4B, the high-resolution response of Ni 2p is composed of two spin−orbit splittings related to Ni 2p 3/2 and Ni 2p 1/2 states with two shakeup satellites.…”

AlP-regulated phosphorus vacancies over Ni–P compounds promoting efficient and durable hydrogen generation in acidic media

“…Surprisingly, when Co 3 Mo/np-Cu was tested at −60 mV vs. RHE for 1000 h, there was nearly no obvious fluctuation because the intermetallic Co 3 Mo nanoparticles were seamlessly integrated into the firm metal skeleton. Apart from these, some reports in the literature also confirm that the dealloyed products have residual active components that cannot be completely dissolved and are rich in O V , 28,29 which are expected to promote the formation of the P V after subsequent phosphating.…”

Bimetallic iron cobalt oxide nanoclusters embedded on three-dimensional flower-like iron cobalt oxide nanosheets for improved oxygen evolution reaction

“…The improved hydrophilic rough surface is beneficial to OER because it exposes more active sites, which speeds up the release of O 2 bubbles and the diffusion of electrolytes. 53,54 Primarily, the electrochemical redox characteristics of the FeCoO NC@3D-FeCoO FeCoO NS|NF electrode demonstrated a small Tafel slope value of ~53 mV dec -1 , which is lower than that of other bimetallic oxides reported in the literature, [57][58][59][60][61][62][63][64][65][66] and is presented in Table 1. The FeCoO NC@3D-FeCoO NS|NF electrode delivered the high mass activity of 500.0 A g -1 at a low overpotential of ~0.22 V, which is more than ~1.5-and ~2.0-times that of the 3D-FeO NS|NF (333.3 A g -1 ), and 3D-CoO NS|NF (250.0 A g -1 ) electrodes.…”

“…4(d), the FeCoO NC@3D-FeCoO NS|NF electrode demonstrated a small Tafel slope value of B53 mV dec À1 , which is lower than that of other bimetallic oxides reported in the literature (Table 1). [57][58][59][60][61][62][63][64][65][66] The FeCoO NC@3D-FeCoO NS|NF electrode exhibited a high mass activity of 500.0 A g À1 at a low overpotential of B0.22 V, which is more than B1.5 and B2.0 times that of the 3D-FeO NS|NF (333.3 A g À1 ) and 3D-CoO NS|NF (250.0 A g À1 ) electrodes. The turnover frequency (TOF) was also calculated to be 2.83 s À1 for the FeCoO NC@3D-FeCoO NS|NF electrode, which is B13.0 and B7.2 times higher than that of the 3D-FeO NS|NF (0.21 s À1 ) and 3D-CoO NS|NF (0.39 s À1 ) electrodes.…”