Three-Dimensional Printed MoS 2 /Graphene Aerogel Electrodes for Hydrogen Evolution Reactions.

In this work, we demonstrate the use of direct ink writing (DIW) technology to create 3D catalytic electrodes for electrochemical applications. Hybrid MoS 2 /graphene aerogels are made by mixing commercially available MoS 2 and graphene oxide powders into a thixotropic, high concentration, viscous ink. A porous 3D structure of 2D graphene sheets and MoS 2 particles was created after post treatment by freeze-drying and reducing graphene oxide through annealing. The composition and morphology of the samples were fully characterized through XPS, BET, and SEM/EDS. The resulting 3D printed MoS 2 /graphene aerogel electrodes had a remarkable electrochemically active surface area (>1700 cm 2 ) and were able to achieve currents over 100 mA in acidic media. Notably, the catalytic activity of the MoS 2 /graphene aerogel electrodes was maintained with minimal loss in surface area compared to the non-3D printed electrodes, suggesting that DIW can be a viable method of producing durable electrodes with a high surface area for water splitting. This demonstrates that 3D printing a MoS 2 /graphene 3D porous network directly using our approach not only improves electrolyte dispersion and facilitates catalyst utilization but also provides multidimensional electron transport channels for improving electronic conductivity.