Fabrication of centimeter-scale MoTe2 layers with high chemical stability for hydrogen evolution application

Abstract

Two-dimensional transition metal dichalcogenides (2D-TMDs) are suitable candidates for the hydrogen evolution reaction (HER) in water splitting. Among the different phases of TMDs, semi-metallic and metallic phases have shown greater efficiency for HER. However, achieving large-scale production of stable, semi-metallic or metallic phases of TMDs is challenging. We report large-scale growth of semi-metallic 1T′-MoTe₂ on three different substrates: sapphire, SiO₂/Si, and fused quartz with an approach to transfer on flexible substrates with increased stability. Due to rapid oxidation of MoTe₂ flakes upon exposure to air, we explored a new transfer strategy using gold deposition to easily transfer flakes from the growth substrate to a flexible substrate. The gold coating ensures protective coverage and acts as a conducting medium after transfer. High activity was observed in MoTe₂ flakes transferred from sapphire, with an onset potential of 280 mV and a Tafel slope of 125 mV/dec. Additionally, the effectiveness of the transfer process in protecting the sample was demonstrated by the absence of oxide formations in the gold-coated MoTe₂ sample for up to one year. These results indicate that the gold-mediated transfer mechanism is suitable for creating flexible HER electrodes based on unstable 2D materials.