MoS<sub>2</sub> Nanosheets Decorated Multi‐walled Carbon Nanotube Composite Electrocatalyst for 4‐Nitrophenol Detection and Hydrogen Evolution Reaction
Dinesh Muthu, K. Muthumalai, Yuvaraj Haldorai, Ramasamy Thangavelu Rajendra Kumar
Abstract
Abstract Various kinds of electrocatalysts have been widely investigated for the reduction of organic pollutants and the production of clean energy resources. Therefore, cost‐effective and stable electrocatalysts are need of the hour. Herein, we synthesized molybdenum disulfide (MoS 2 ) decorated multi‐walled carbon nanotubes (MWCNTs) composite using a hydrothermal method for efficient hydrogen production and electrochemical detection of 4‐nitrophenol (4‐NP). X‐ray diffraction and Raman analysis confirmed the successful formation of the MWCNTs/MoS 2 composite. SEM images showed that the pristine MoS 2 exhibited a flower‐like morphology with an average particle diameter of 3 μm. Transmission electron microscopy proved that the MoS 2 nanosheets were decorated on the MWCNTs surface. The composite showed good performance in terms of electrochemical reduction of 4‐NP in 0.1 M phosphate buffer (pH 7.0). The linear sweep voltammetric response of the composite electrode for sensing of 4‐NP exhibited a linear relation with the concentration range of 0.75–71 μM and a low detection limit of 0.47 μM. The composite electrode showed high sensitivity (1.67 μA/μM/cm 2 ), good stability, and excellent selectivity. The MWCNTs/MoS 2 composite exhibited superior electrocatalytic activity in the hydrogen evolution reaction relative to the MoS 2 catalyst. The composite coated carbon cloth showed a low overpotential of 211 mV for hydrogen evolution in 0.5 M H 2 SO 4 . The electrocatalyst split water into hydrogen up to 22 h with a Tafel slope of 136 mV/dec.