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This content will become publicly available on July 23, 2026

Title: Electrocatalytic Performance of M 5 X 4 MXenes for Hydrogen Evolution Reaction
Abstract M5X4MXenes, a subclass of 2D transition metal carbides, have attracted attention as the thickest 2D material synthesized. Early studies show their promising electrocatalytic activity but overlooked how metal composition and interlayer spacing affect hydrogen evolution reaction (HER). To address this gap, three M5X4MXenes, Mo4VC4, (TiTa)5C4, and (TiNb)5C4, are systematically studied and their interlayer spacing and composition modulated through ion exchange with tetramethyl ammonium (TMA+vs. Li+), providing new insights into their HER activity. These findings reveal that TMA+‐intercalated Mo4VC4exhibits superior HER activity, achieving areal and gravimetric overpotentials of 172 and 90 mV, respectively, due to its composition (presence of Mo) and expanded interlayer spacing that enhances proton accessibility. The Li+exchange increases the overpotential to 212 and 131 mV at 10 mA areal and gravimetric current density, respectively, as reduced interlayer spacing restricts access to active Mo sites. In contrast, (TiNb)5C4and (TiTa)5C4display higher overpotentials, making them more suitable for supercapacitor or aqueous battery applications due to the wider electrochemical window. This study provides critical insights into the interplay between metal composition and interlayer engineering in M5X4MXenes, establishing TMA‐Mo4VC4as a promising candidate for sustainable hydrogen production.  more » « less
Award ID(s):
2318105
PAR ID:
10633632
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
Wiley
Date Published:
Journal Name:
Small
ISSN:
1613-6810
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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