Deeply Reconstructed NiFe Layered Double Hydroxide Nanosheets for an Efficient Oxygen Evolution Reaction

Abstract

Layered double hydroxide (LDH) has shown great promise for oxygen evolution reaction (OER) in an alkaline solution, but its catalytic performance is still hindered by inadequate active sites and large overpotentials. Here, we report a robust solvothermal reconstruction strategy that can induce rich cavities and active sites in fluorinated NiFe LDH (NiFe-F) electrocatalysts for excellent OER activities. In the process of reconstruction, partial fluoride ions and metal cations (Fe3+) are leached from the catalyst in the alkaline solution at an elevated temperature. This leads to an effective bulk and surface reconstruction, drastically increasing the electrochemical active surface area and exposing more catalytic active sites, therefore improving the kinetics of the reaction and optimizing the binding energy of OER intermediates, as evidenced in our systematic electrochemistry studies and the density functional theory calculations. The reconstructed NiFe-F catalyst exhibits an unprecedented high activity toward OER among the non-noble metal catalysts, with a low overpotential (η) of 152 mV at 10 mA cm–2, high turnover frequency of 1.6 × 10–1 s–1 at η = 200 mV, and small activation energy of 12.8 kJ mol–1 at 1.23 VRHE, and excellent stability in the chronopotentiometry at 10 mA cm–2 for 100 h. This study offers a robust reconstruction strategy toward OER catalyst design for the next-generation clean energy conversion.

CoNiFe‐layered double hydroxide decorated Co‐N‐C network as a robust bi‐functional oxygen electrocatalyst for zinc‐air batteries

“…The electrochemical double layer capacitance ( C dl ) was evaluated using cyclic voltammetry (CV) in the non‐Faradaic range at several scan rates (Figure S7a,b). It can be visualized that C dl of Co‐N‐C@CoNiFe‐LDH is 4.8 mF cm −2 , which is superior to that of pristine NiFe‐LDH 35,36 . It confirms that Co‐N‐C@CoNiFe‐LDH possesses the high specific surface area which is in line with BET surface area.…”

Research status, opportunities, and challenges of cobalt phosphate based materials as OER electrocatalysts

“…These active sites may possess higher adsorption abilities and enhanced electron transfer properties, thereby promoting the OER. 106 The leaching of phosphoric acid during the OER process leads to an increase of the specific surface area of the catalyst and the exposure of more active sites.…”

Strong Electron Interaction at the Amorphous/Crystalline Interface Enables Advanced Oxygen Evolution Reaction

“…Electrochemical water splitting coupled with a renewable energy source for preparing green hydrogen provides great potential to achieve carbon neutrality. , Two half-reactions of oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction (HER) at the cathode are included. − In comparison to the one-electron HER process, the completed four-electron reaction process of OER hinders the efficiency of overall water splitting. − Therefore, the development of high-performance OER catalysts is a key aspect of water electrolysis. − Different from the water electrolysis in acid, that in alkaline or neutral conditions exhibits a lower requirement for anticorrosion. − For example, both of them can be driven by nonprecious metal-based electrocatalysts such as Fe, Co, Ni, etc. − Though they have an advantage over precious metal catalysts in terms of price, their high overpotential, poor electrical conductivity, and slow electron-transfer process are still far from practical application. − Moreover, neutral electrolysis is mostly based on phosphate-buffered solution (PBS), which generally produces low current densities and requires extra energy for the water dissociation process due to the low OH – concentration. , Therefore, the development of basic and neutral OER catalysts faces serious challenges. , …”