2D Metal-based Electrocatalysts: Properties and Applications

초록

Metallic nanostructures with thickness ranging from a single atom up to 100 nanometers fall under the category of 2D metals. The modified electronic band structure due to quantum confinement effects leads to intriguing electrical and electronic properties. Moreover, the properties can be further altered by variations in their shape, thickness, and lateral size. The exceptionally high surface area to volume ratio of 2D metals and stretchability are beneficial in electrocatalysis. The exposed atoms on the outer surface of 2D metals with low coordination numbers, possess unique properties, forming numerous active sites on the surface. As a result, 2D metals demonstrate a high ability towards the activation of small molecules, including O2, H2, CO2, HCOOH, CH3OH, C2H5OH, etc. This exceptional oxidation reactivity enables 2D metals to be excellent electrocatalysts for hydrogen/oxygen evolution reaction (HER/OER), oxygen reduction reaction (ORR), and oxidation of small molecules (formic acid, methanol, and ethanol) for fuel-cell applications. As the localized surface plasmon resonance (SPRs) is sensitive to the size/shape of plasmonic 2D metals, the optical absorption enabled by SPRs offers additional advantages for photo-electrocatalytic processes. The stability of highly active catalytic 2D metals presents a challenge due to the propensity of metal surfaces with high reactivity to undergo oxidation. Recent developments in the synthesis, properties, and applications of 2D metal nanostructures for electrocatalytic processes are discussed. The challenges and opportunities in the electrocatalytic application of 2D metal nanostructures have been summarized. © 2025 Ram K. Gupta.