Large-area freestanding 2D Ni/Co vertical heterostructures with strong interfacial coupling for efficient oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Designing 2D vertical heterostructures from ultrathin nanosheets enhances energy conversion by optimizing catalytic sites and interfacial charge migration.
• Transition metal hydroxides face challenges like disordered stacking and synthesis complexity, hindering their application in catalysis.
• Anisotropic crystal growth in non-layered systems is crucial but difficult to achieve.

Purpose of the Study:

• To synthesize ultrathin 2D nickel/cobalt hydroxide vertical heterostructures.
• To investigate their performance as electrocatalysts for the oxygen evolution reaction (OER).
• To understand the role of interfacial interactions in OER activity through experimental and theoretical analysis.

Main Methods:

• Wet-chemical synthesis of ultrathin 2D nickel/cobalt hydroxide vertical heterostructures.
• Electrocatalytic testing for OER performance, including overpotential and Tafel slope measurements.
• Density Functional Theory (DFT) analysis to probe interfacial interactions and reaction mechanisms.

Main Results:

• The synthesized vertical heterostructures exhibited efficient OER electrocatalysis.
• An overpotential of 364 mV was achieved at 10 mA cm^-2 with a Tafel slope of 70 mV dec^-1.
• DFT analysis confirmed that interfacial interaction is critical for OER activity.

Conclusions:

• Ultrathin 2D vertical heterostructures offer an effective strategy for designing high-performance electrocatalysts.
• The synthesized nickel/cobalt hydroxide heterostructures demonstrate significant potential for OER applications.
• Optimized interfacial engineering is key to maximizing material utilization and catalytic efficiency in 2D heterointerface-based electrocatalysts.