Integrating PtNi nanoparticles on NiFe layered double hydroxide nanosheets as a bifunctional catalyst for hybrid sodium–air batteries

Abstract

<p>Hybrid sodium-air batteries (HSABs) are emerging systems for next-generation energy storage owing to high theoretical energy density, high specific capacity, low cost, and environmental friendliness. However, ungratified energy efficiency, large...</p>

Sub-Nanometer Pt Clusters on Defective NiFe LDH Nanosheets as Trifunctional Electrocatalysts for Water Splitting and Rechargeable Hybrid Sodium–Air Batteries

“…Recent evidence suggests that the generation of cation vacancies into NiFe LDHs is an effective route to optimize surface electronic and chemical features, improving their electronic conductivity and electrocatalytic activity. , Pt is generally considered as the unrivaled electrocatalyst for the HER, but the catalytic activity in the alkaline environment is about 2 orders of magnitude lower than that in acidic electrolytes. , Pioneering works have proved that the integration of Pt into metal hydroxides is a plausible way to enhance the HER activity of Pt in basic media . Among various transition metal hydroxides, NiFe LDHs exhibit considerable potential as supports to immobilize Pt due to the strong synergetic interactions between Pt and site-specific supports. ,− Notwithstanding the superior properties of Pt-based catalysts, the high cost, scarcity, and poor durability significantly limit their universal application . Therefore, how to reduce the material cost while maintaining high catalytic performance has been a hot research topic in recent decades .…”

“…One economical strategy is alloying Pt with transition metals catalysts; thus, the electrocatalytic performance can be enhanced through the ensemble and ligand effects . For example, our team has successfully fabricated a PtNi bimetallic structure on the NiFe LDHs surface by a multistep method, which displays excellent bifunctional catalytic activity toward the OER/ORR under basic conditions . It was widely accepted that Ni atoms are easily corroded in the electrocatalytic ORR reaction; hence, the alloy structure cannot maintain good durability in the long-term hybrid sodium–air battery (HSAB) rechargeability testing. , Another effective approach is to increase the atom utilization efficiency by reducing the particle size, thereby providing more active sites and improving specific activity .…”

“…For example, our team has successfully fabricated a PtNi bimetallic structure on the NiFe LDHs surface by a multistep method, which displays excellent bifunctional catalytic activity toward the OER/ORR under basic conditions . It was widely accepted that Ni atoms are easily corroded in the electrocatalytic ORR reaction; hence, the alloy structure cannot maintain good durability in the long-term hybrid sodium–air battery (HSAB) rechargeability testing. , Another effective approach is to increase the atom utilization efficiency by reducing the particle size, thereby providing more active sites and improving specific activity . Unfortunately, Pt nanoparticles tend to spontaneously agglomerate and coagulate owing to their high surface energy, and some capping/stabilizing agents including organic ligands, polymers, and surfactants are usually utilized to prevent their aggregation .…”

Encapsulation of Pt Nanocrystals inside Pyrolyzed UiO-66-NH2 Metal–Organic Framework Supports as Oxygen Reduction Catalysts

“…However, it is demanding to search for clean, sustainable, and feasible new energy for our use . Fuel cells, and metal–air batteries are drawing in huge attention among various promising power technologies. − In particular, rechargeable zinc–air batteries (ZABs) are hopeful applicants because of their minimal expense, high energy density, and reliability. − Nonetheless, their commercial applications have been truly hindered by poor oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). , Currently, Pt-based catalysts have shown remarkable electrocatalytic activity for ORR. − Nevertheless, there are some hurdles that restrict the commercial use of Pt/C. In particular, Pt is a somewhat costly metal and likely to dissolve and agglomerate under harsh operating conditions, bringing about a costly catalyst with inadequate electrocatalytic durability. , The corrosion of the carbon support and dissolution of Pt caused by carbon corrosion have been admitted to be the chief degradation processes.…”

NiFe Layered-Double-Hydroxide Nanosheet Arrays on Graphite Felt: A 3D Electrocatalyst for Highly Efficient Water Oxidation in Alkaline Media

“…The exhaustion of fossil fuels and the worsening of environmental pollution have promoted the development of green and sustainable technology to alleviate the energy crisis. Hydrogen energy has attracted wide attention owing to their high calorific value, sustainability, and environmental friendliness. − Water electrolysis is an attractive alternative technology for hydrogen production. − The overall efficiency of water electrolysis is mainly determined by oxygen evolution reaction (OER), which, however, is limited by its sluggish kinetics. − To date, IrO 2 and RuO 2 exhibit the most active activity toward four-electron water oxidation reaction (WOR 4e – ) but suffer from scarcity and high price. − Similarly, electrocatalysts for water oxidation in acidic media are also scarce and expensive, the electrocatalysts should be acid-insoluble and stable, and that could hinder their industrial application, whereas electrocatalysts in alkaline media could simplify and reduce the cost of a water electrolysis system. , Accordingly, there is an urgent push to develop high-performance non-noble-metal-based OER electrocatalysts in an alkaline environment.…”