Ultrathin nickel-cobalt inorganic-organic hydroxide hybrid nanobelts as highly efficient electrocatalysts for oxygen evolution reaction

Boosting the oxygen evolution electrocatalysis of high-entropy hydroxides by high-valence nickel species regulation

“…Specifically, the TOF value of HEH is as big as 0.139 s −1 ( η = 350 mV), superior to other previous Co 0.8 Ni 0.2 (OH)(BzO)·H 2 O 0.026 s −1 ( η = 350 mV), F-Ni 3 S 2 0.021 s −1 ( η = 350 mV), and Ni-CP-CNT-H 0.118 s −1 ( η = 395 mV). 32–34 The increased TOF value and the delivered OER current density are simultaneously consistent with the increasing trend of the Ni 3+ /Ni 2+ ratio, suggesting the positive role of the high-valence state Ni species (Fig. 4b).…”

“…Specifically, the TOF value of HEH is as big as 0.139 s À1 (Z = 350 mV), superior to other previous Co 0.8 Ni 0.2 (OH)(BzO)ÁH 2 O 0.026 s À1 (Z = 350 mV), F-Ni 3 S 2 0.021 s À1 (Z = 350 mV), and Ni-CP-CNT-H 0.118 s À1 (Z = 395 mV). [32][33][34] The increased TOF value ) can decrease the reaction barrier and thereby enhance the OER catalytic performance (Fig. 4c).…”

Hierarchical MoO42– Intercalating α-Co(OH)2 Nanosheet Assemblies: Green Synthesis and Ultrafast Reconstruction for Boosting Electrochemical Oxygen Evolution

“…Based on the Co content calculated from the integrated result of the Co 2+ /Co 3+ oxidation peak, the CoOOH(25) has a TOF of 0.018 s –1 at the same overpotential. The TOF of CoOOH(25) is higher than that of liquid exfoliated CoCo LDH nanosheets (<0.005 s –1 at η = 300 mV), CoP@RGO hybrid (about 0.015 s –1 at η = 350 mV), Fe 1 Co 1 oxide nanosheets (0.022 s –1 , η = 350 mV), comparable to Mo-enriched CoOOH derived from Co–Mo 2 C heterostructure (about 0.027 s –1 at η = 330 mV) and the Co 0.8 Ni 0.2 (OH)­(BzO)·H 2 O (BzO = benzoate) nanobelts (0.026 s –1 , η = 350 mV). ,,− The surface oxygen vacancies and the disordered structure caused by structure reconstruction will synergistically contribute to the improvement of the overall OER catalytic performance. The remarkable electrocatalytic performance for OER with higher activity and favorable kinetics of in situ formed CoOOH(25) may be attributed to the following reasons: (i) the ultrafast and thorough generation of high valence CoOOH as the real active phase with high conductivity and stability; (ii) high surface area and more exposed active sites originating from the ultrathin nanosheets with severe structural distortion; (iii) high intrinsic activity enhanced by the oxygen vacancy engineering; (iv) and their synergistic effects.…”

Recent advances in non‐precious Ni‐based promising catalysts for water splitting application

“…Nickel-cobalt nanosheets as presented in Figure 10A-C at various ratios on Ni-foam by thermal method have applied in electrocatalysts that documented minimum Tafel slope of 35 mV À1 and overpotential of 247 mV at 10 mA/cm 2 current density. 87 Chi et al prepared hexagon Ni-Co hydroxide nanoplates which were annealed at 400 C for 2 h to obtain the oxide phase. The oxide exhibited a good catalytic activity with 394 mV overpotential at a current density of 10 mA/cm 2 comparatively with hydroxides.…”

“…Insertion of other metals into NiO may produce a three‐dimensional (3D) structure for enhancing the active surface, boosting the catalytic activity in comparison with phase pure metal oxides. Nickel‐cobalt nanosheets as presented in Figure 10A‐C at various ratios on Ni‐foam by thermal method have applied in electrocatalysts that documented minimum Tafel slope of 35 mV −1 and overpotential of 247 mV at 10 mA/cm 2 current density 87 . Chi et al prepared hexagon Ni‐Co hydroxide nanoplates which were annealed at 400°C for 2 h to obtain the oxide phase.…”