A limited anodic and cathodic potential window of MoS2: limitations in electrochemical applications

Abstract

Molybdenum disulphide has been touted as a good material with diverse possible applications such as an energy storage and sensing platform. However, we demonstrate here the limitation of MoS₂ as an analytical sensing platform due to the limited potential window in both the anodic and cathodic regions attributed to the inherent electrochemistry (oxidation of Mo⁴⁺ to Mo⁶⁺) and the catalytic hydrogen evolution reaction due to H₃O⁺ reduction on the MoS₂ surface, respectively. The electrochemical window of MoS₂ lies in the region of ∼–0.6 V to +0.7 V (vs. AgCl). We show that such a limited working potential window characteristic of MoS₂ precludes the detection of important analytes such as nitroaromatic explosives, pesticides and mycotoxins which are instead detectable on carbon surfaces. The limited potential window of MoS₂ has to be taken into consideration in the construction of electroanalytical devices based on MoS₂.