Multiple structural defects in ultrathin NiFe-LDH nanosheets synergistically and remarkably boost water oxidation reaction

Abstract

Developing highly active, cost-effective and stable electrocatalysts for oxygen evolution reaction (OER) is critical to renewable energy systems. Herein, we demonstrate a H2O2-assisted etching method to synthesize mesoporous NiFe layered double hydroxide nanosheets (LDHs) on nickel foam (NF) (NiFe LDHMs/NF). The NiFe LDHMs/NF processed with 200 μL H2O2 exhibited excellent OER performance with an extraordinarily low overpotential of 170 mV at 10 mA cm -2 in 1 M KOH, as well as superior kinetics with a Tafel slope of 39.3 mV dec -1 , being the one of the best non-precious electrocatalysts reported to date. Density functional theory (DFT) calculations revealed that the excellent OER performance arose from pseudo re-oxidized meta-stable Ni 3+ , which evidently suppressed 3d-eg of Ni-site and elevated d-band center towards competitively low electron-transfer barrier. The Fe-sites within the system robustly preserved Ni oxidation state and maintained electron-transfer activities. This protocol is applicable to developments of high-efficiency non-precious metal OER electrocatalysts.

In situ Raman spectroscopy reveals the structure evolution and lattice oxygen reaction pathway induced by the crystalline–amorphous heterojunction for water oxidation

“…The oxygen vacancy of the catalyst can be roughly estimated from the ratio of O2 to O1. 15 It suggests that there are abundant oxygen vacancies in the electrocatalyst, which is beneficial for the rapid reconstruction of the electrocatalysts. The subsequent OER catalytic activity tests further verified that the catalyst with a Ni/Fe ratio of 3 : 1 (Ni 3 Fe 1 ) presented the best performance.…”

Two Birds with One Stone: Contemporaneously Boosting OER Activity and Kinetics for Layered Double Hydroxide Inspired by Photosystem II

“…The well‐resolved lattice fringes with a spacing of 0.25 nm can be assigned to the (012) plane of NiFe‐LDH. [ 17 ] In addition, the selected area electron diffraction (SAED) pattern in Figure 1d displays the Debye‐Scherrer rings, which can be indexed to the (113), (012), (101), and (018) planes of NFCL(70)‐LDH. All of the above reveal the successful in situ preparation of NiFe‐LDH integrated electrode on Ni foam.…”

A processable Prussian blue analogue-mediated route to promote alkaline electrocatalytic water splitting over bifunctional copper phosphide

“…7,8 In spite of the excellent activity of the state-of-the-art electrocatalysts (the noble-metal-based compounds) for the HER and OER, the natural scarcity and high price strongly limit their large-scale applications. 9 To address this issue, the development of noble metal-free electrocatalysts has been a continuous pursuit, in which Earthabundant transition metal-based oxides, 10 hydroxides, 11 selenides, 12 phosphides, 13 sulfides, 14 their composites etc. have been demonstrated as efficient alternatives for noble metalbased electrocatalysts.…”