Magnetron Sputter-Coated Nanoparticle MoS2 Supported onNanocarbon: A Highly Efficient Electrocatalyst towardthe Hydrogen Evolution Reaction

摘要

The design and fabrication of inexpensive highly efficient electrocatalysts for the production of hydrogen via the hydrogen evolution reaction (HER) underpin a plethora of emerging clean energy technologies. Herein, we report the fabrication of highly efficient electrocatalysts for the HER based on magnetron-sputtered MoS2 onto a nanocarbon support, termed MoS2/C. Magnetron sputtering time is explored as a function of its physiochemical composition and HER performance; increased sputtering times give rise to materials with differing compositions, i.e., Mo⁴⁺ to Mo⁶⁺ and associated S anions (sulfide, elemental, and sulfate), and improved HER outputs. An optimized sputtering time of 45 min was used to fabricate the MoS2/C material. This gave rise to an optimal HER performance with regard to its HER onset potential, achievable current, and Tafel value, which were −0.44 (vs saturated calomel electrode (SCE)), −1.45 mV s^–1, and 43 mV dec^–1, respectively, which has the highest composition of Mo⁴⁺ and sulfide (MoS2). Electrochemical testing toward the HER via drop casting MoS2/C upon screen-printed electrodes (SPEs) to electrically wire the nanomaterial is found to be mass coverage dependent, where thecurrent density increases up to a critical mass (ca. 50 μg cm^–2), after which a plateau is observed. To allow fora translation of the bespoke fabricated MoS2/C from laboratoryto new industrial applications, MoS2/C was incorporatedinto the bulk ink utilized in the fabrication of SPEs (denoted asMoS2/C-SPE), thus allowing for improved electrical wiringto the MoS2/C and resulting in the production of scalableand reproducible electrocatalytic platforms. The MoS2/C-SPEsdisplayed far greater HER catalysis with a 450 mV reduction in theHER onset potential and a 1.70 mA cm^–2 increasein the achievable current density (recorded at −0.75 V (vsSCE)), compared to a bare/unmodified graphitic SPE. The approach ofusing magnetron sputtering to modify carbon with MoS2 facilitatesthe production of mass-producible, stable, and effective electrodematerials for possible use in electrolyzers, which are cost competitiveto Pt and mitigate the need to use time-consuming and low-yield exfoliationtechniques typically used to fabricate pristine MoS2.