Engineering metallic MoS2 monolayers with responsive hydrogen evolution electrocatalytic activities for enzymatic reaction monitoring

Abstract

The use of a Schlenk line (SL) promotes a strategy involving N-butyllithium for the chemical exfoliation of layered crystals, with the remarkable merits of being low risk and allowing “one-pot” operation. Significantly, metallic-phase and defect-abundant nanosheets are synthesized from SL-exfoliated molybdenum disulphide (SL-MoS₂), exhibiting the desired morphological features with a high percentage of monolayers and uniform planar size. Additionally, SL-MoS₂ has the excellent structural features of a metallic phase and abundant defects, thereby supporting high activity during the electrocatalytic hydrogen evolution reaction (HER). Nevertheless, the unique structural and morphological characteristics of SL-MoS₂ are proved to cause the rapid dissociation of the SL-MoS₂ nanosheets in H₂O₂-rich environments, and the electrocatalytic performance accordingly declines. The HER current density, which is dependent on the number of active sites of SL-MoS₂, specifically reflects the reactive-oxygen-species-based degradation of the SL-MoS₂ nanoprobes; this can contribute to the electrochemical monitoring of enzyme-associated biological targets and processes using developed chips based on SL-MoS₂-modified carbon fibers.