Enhanced supercapacitor performance and hydrogen evolution reaction using Nb 2 CT x MXene-integrated HKUST-1 MOF

Abstract

This work aims to investigate how HKUST-1 metal-organic framework (MOF) and Nb2CTx MXene operate in concert to improve the catalytic activity in the hydrogen evolution reaction (HER) and the effectiveness of supercapacitors. While HKUST-1 offers a very porous structure that is favorable for charge storage, Nb2CTx serves as both a conductive substrate and a catalytic site for HER. This combination leads to better charge transfer channels and increased electroactive sites, which ultimately results in higher HER efficiency (shown by a notably lower Tafel slope of 52.42 mV/dec). In configurations of two and three electrodes, a specific capacity of 2168 C/g at a current density of 1.0 A/g is demonstrated by HKUST-1/Nb2CTx Moreover, the theHKUST-1/Nb2CTx combination, in particular the HKUST-1/Nb2CTx//AC composite, shows remarkable stability; after 1000 cycles, they still retain 95 % of their capacity and achieve 97% coulombic efficiency. The HKUST-1/Nb2CTx decorated electrode exhibited energy and power density, reaching approximately 89 Wh/kg and 938 W/kg in two-electrode (real device) configurations. These results highlight the HKUST-1/Nb2CTx composite excellent potential in energy conversion and storage applications.