Extending the Colloidal Transition Metal Dichalcogenide Library to ReS 2 Nanosheets for Application in Gas Sensing and Electrocatalysis.

Among the large family of transition metal dichalcogenides, recently ReS ₂ has stood out due to its nearly layer-independent optoelectronic and physicochemical properties related to its 1T distorted octahedral structure. This structure leads to strong in-plane anisotropy, and the presence of active sites at its surface makes ReS ₂ interesting for gas sensing and catalysts applications. However, current fabrication methods use chemical or physical vapor deposition (CVD or PVD) processes that are costly, time-consuming and complex, therefore limiting its large-scale production and exploitation. To address this issue, a colloidal synthesis approach is developed, which allows the production of ReS ₂ at temperatures below 360 °C and with reaction times shorter than 2h. By combining the solution-based synthesis with surface functionalization strategies, the feasibility of colloidal ReS ₂ nanosheet films for sensing different gases is demonstrated with highly competitive performance in comparison with devices built with CVD-grown ReS ₂ and MoS ₂ . In addition, the integration of the ReS ₂ nanosheet films in assemblies together with carbon nanotubes allows to fabricate electrodes for electrocatalysis for H ₂ production in both acid and alkaline conditions. Results from proof-of-principle devices show an electrocatalytic overpotential competitive with devices based on ReS ₂ produced by CVD, and even with MoS ₂ , WS ₂ , and MoSe ₂ electrocatalysts.
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