Two-Dimensional NH 4 V 3 O 8 Nanoflakes as Efficient Energy Conversion and Storage Materials for the Hydrogen Evolution Reaction and Supercapacitors

• Published in: ACS omega Vol. 7; no. 29; pp. 25433 - 25442
• Main Authors: Le, Phuoc-Anh, Le, Van-Qui, Tran, Thien Lan, Nguyen, Nghia Trong, Phung, Thi Viet Bac, Dinh, Van An
• Format: Journal Article
• Language: English
• Published: United States 26.07.2022
• DOI: 10.1021/acsomega.2c02375
• ISSN: 2470-1343

Herein, for the first time, we present two-dimensional (2D) NH V O nanoflakes as an excellent material for both energy conversion of the hydrogen evolution reaction and storage of supercapacitors by a simple and fast two-step synthesis, which exhibit a completely sheet-like morphology, high crystallinity, good specific surface area, and also stability, as determined by thermogravimetric analysis. The 2D-NH V O flakes show an acceptable hydrogen evolution performance in 0.5 M H SO on a glassy carbon electrode (GCE) coated with 2D-NH V O , which results in a low overpotential of 314 mV at -10 mA cm with an excellent Tafel slope as low as 90 mV dec . So far, with the main focus on energy storage, 2D-NH V O nanoflakes were found to be ideal for supercapacitor electrodes. The NH V O working electrode in 1 M Na SO shows an excellent electrochemical capability of 274 F g at 0.5 A g for a maximum energy density of 38 W h kg at a power density as high as 250 W kg . Moreover, the crystal structure of 2D-NH V O is demonstrated by density functional theory (DFT) computational simulation using three functionals, GGA, GGA + , and HSE06. The simple preparation, low cost, and abundance of the NH V O material provide a promising candidate for not only energy conversion but also energy-storage applications.