PtRh and PtRh/MoS2 nano-electrocatalysts for methanol oxidation and hydrogen evolution reactions

A synthesis of PtRh and PtRh covered with MoS2 nanoelectrocatalysts obtained by means of a scalable, economic, wet chemistry approach is proposed. The synthesized nanocatalysts were broadly characterized: XRD, SEM and TEM images and EDX maps showed the formation of bimetallic PtRh alloy nanoparticles, which in the second sample were covered with MoS2 nanosheets. Firstly, the electrocatalytic activity of the synthesized materials was tested towards hydrogen evolution reaction (HER), showing excellent properties: negligible overpotentials and very small Tafel slopes (18 mV/decade and 32.7 mV/decade for PtRh and PtRh-MoS), respectively. The samples exhibited also high stability over time towards HER, especially PtRh/MoS2. Secondly, the catalysts were tested towards methanol oxidation reaction (MOR), showing low onset potentials (0.18 V for PtRh and 0.07 V for PtRh/MoS2) and very high If/Ib ratio (4.66 for PtRh and 2.37 PtRh/MoS2). The results obtained in this work evidence the outstanding performances of the synthesized nano-electrocatalysts.