Fluorine-free synthesized tantalum carbide (Ta2C Mxene) as an efficient electrocatalyst for water reduction and nitro compound reduction

Abstract

One of the eco-sustainable sustainable ways to generate hydrogen, which is considered a clean energy source, involves the electrochemical process. On the other hand, identifying the most effective heterogeneous catalyst is crucial for amine synthesis from nitro compounds in order to determine the optimum catalytic activity, stability, and reusability. Herein, we report the preparation of a 2D tantalum carbide MXene via the fluorine-free etching method and its application in catalysis (nitro reduction) and electrocatalysis (HER and nitro reduction). It is well-known that due to their layered structure, MXenes show better catalytic activities, and hence they find applications in catalysis. Ta2AlC (MAX phase) and Ta2C (MXene) were evaluated for their electrocatalytic activity in the hydrogen evolution reaction. The electrocatalyst Ta2C MXene exhibited overpotentials of 223 mV to reach 10 mA cm−2 current density when tested under standard HER conditions (0.5 M H2SO4), and furthermore, the electrocatalytic reduction behavior of Ta2C MXene towards the electrochemical reduction of 4-NP was tested in 1 M KOH. Galvanostatic electrolysis was performed in a divided cell using Ta2C modified carbon cloth as the cathode, and Pt as the anode separated by a Nafion membrane, and it showed 72% product conversion and 96% faradaic efficiency. The progress of the galvanostatic electrolysis was monitored using ex situ Raman and UV-Vis spectroscopy. Similarly, the reducing behavior of Ta2C towards the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 was tested. The Ta2C MXene displayed improved catalytic activity with pseudo-first-order kinetics. Ta2C nanoparticles completely reduced all three nitro compounds (10 mL each), 4-NP (216 μM-17 min), 2,4-dinitrophenol DNP (163 μM-25 min) and 2,4,6-trinitrophenol TNP (131 μM-36 min). Furthermore, in all these studies, the Ta2C MXene exhibited improved catalytic performance and stability.