Ammonia borane assisted mechanochemical boost of electrochemical performance of basal planes of MoS2-type materials

Abstract

The maximization of the number of exposed edges of layered MoS2-type transition metal dichalcogenides of general formula MX2 (M = Mo, W; X = S, Se) is difficult yet meaningful way to improve their electrochemical and electrocatalytic performance. In this work, an all-solid ball milling method for simultaneous introduction of defects and their hybridization through binding of ammonia borane (NH3BH3) to defect sites of MX2 is demonstrated. The milling conditions leads to partial separation and nanosizing of MX2 layers, simultaneously extensively introducing defects (cracks, vacancies, strains, voids etc.), while the detailed analysis revealed the functionalization of the material by binding of NH3BH3 to defect sites, which results in highly improved electrocatalytic performance of thus obtained composites with respect to MX2 for hydrogen evolution reaction. The mechanochemical approach thus enables preparation of MoS2-type materials with improved, highly tunable activity, potentially relevant for energy conversion and storage.