Robust and Promising Electrocatalytic Oxygen Evolution Reaction by Activated Cu–Co–B Amorphous Nanosheets

Abstract

The challenge to develop a highly efficient and affordable electrocatalyst for the oxygen evolution reaction (OER) could be fulfilled by a newly developed transition metal boron amorphous alloy electrocatalyst. This could successfully improve the overall efficiency of the electrochemical water splitting. Herein, we demonstrate the development of an entirely new Cu−Co−B amorphous alloy nanosheet (NS), which can act as an industrially promising electrocatalyst for the OER. Among a series of studied compositions, surface activated CuCo 2 B NSs with 5−6 nm thickness offer highly promising OER performances with an exceptionally high current density of 1000 mA cm −2 at 270 mV of overpotential (η) in a 1.0 M KOH electrolyte. It can also afford η 100 = 204 mV and η 500 = 256 mV, which remains intact for 60 h, with the lowest Tafel slope and charge transfer resistance and the highest electrochemically active sites with a promising turnover frequency and 87% Faradaic efficiency. It also fulfills the commercial requirement criteria of the OER process in 30 wt % KOH. Extensive experimental analyses led to a Cu−Co synergistic-based mechanism by the in situ formed active sites for the adsorption of *OH and *OOH reaction species, reconstruction of the catalyst surface by forming a metal hydroxides/oxyhydroxides precatalyst, modulation of electronic structure due to the rich defect nature, and topological disorder of the amorphous catalyst. Density functional theory (DFT) studies reveal that CuCo 2 B NSs are the most promising candidates for OER due to the lowest barrier for OER and thus the lowest adsorption energies, and the Cu-centers effectively and synergistically enhance the OER.

Designing Nanoarchitecture of NiCu Dealloyed Nanoparticles on Hierarchical Co Nanosheets for Alkaline Overall Water Splitting at Low Cell Voltage

“…It is evident that the nanocomposite NCDC shows the lowest adsorption energies and hence has the lowest energy barrier and acts as a better catalyst for OER activity. NC and NCD have higher barriers as they show strong adsorption with the active species. ,, …”

Ultrafast Thermal Synthesis of Non-Noble Metal-Based Electrocatalysts for Overall Water Splitting

“…Figure c shows that NiFe@ACF has a small Tafel slope of ∼83 mV dec –1 , which is much smaller than that of Ni@ACF, Fe@ACF, ACF, and Ir/C@ACF, suggesting the favorable OER kinetics of NiFe@ACF. Considering the Tafel slope of ∼83 mV dec –1 for the NiFe@ACF, either the one electron-transfer step (M + OH – ↔ MOH + e – ) or the electron–proton-transfer step (MOOH + OH – ↔ MOO + H 2 O + e – ) is the rate-determining step. − Compared with Fe@ACF and Ni@ACF, NiFe@ACF has a much smaller Tafel slope and a much lower overpotential. It implies that the synergistic effect between Ni and Fe in NiFe@ACF could enhance OER catalytic activity. ,, In addition, a chronopotentiometric test was carried out continuously at a current density of ∼10 mA cm –2 to measure durability of the NiFe@ACF in 1 M KOH.…”

Hierarchical UiO-66(−NH2)/CuInS2 S-Scheme Photocatalyst with Controlled Topology for Enhanced Photocatalytic N2 Fixation and H2O2 Production

“…In addition, the presence of the Cu(I) species in the heterostructure material is further confirmed from the Cu LLM spectra which show a characteristic peak at 568.6 eV (Figure 4b). 41 The In 3d spectra exhibit two distinct peaks at 444.83 and 452.3 eV, ascribed to In 3d 5/2 and 3d 3/2 states, and these peaks show a minimal shift toward lower binding energy in the case of heterostructure material (Figure 4c). 42 The S 2p spectrum of pure CIS contains two peaks at 160.9 and 162.0 eV due to photoelectron emission from S 2p3/2 and 2p1/2 microstates of lattice S 2− species (Figure 4d).…”

“…The high resolution Cu 2p spectra of pure CIS exhibits a doublet located at 931.77 and 953.6 eV associated with Cu 2p 3/2 and 2p 1/2 microstates of Cu(I) species (Figure 4a). 41 The corresponding binding energies of Cu(I) in the heterostructure display a shift toward a lower binding energy region by 0.3 eV.…”