Effect of Pt-Mn nanoparticles supported on CNT in methanol electro-oxidation reaction, experimental, and theoretical studies

This work reports the facile synthesis of Pt-Mn nanoparticles supported on multiwall carbon nanotubes using the Brust–Schiffrin method and their electrochemical performance during methanol electro-oxidation reaction. According to the topographical and structural results, the Pt-Mn nanoparticles present high dispersion with a narrow size distribution of ~ 2.5 nm. Meanwhile, the electrochemical evaluation exhibits a greatly enhanced electrocatalytic activity. The electrocatalyst's performance improves as Mn increased up to 40 at.% in Pt nanoparticles, but it decreases as Mn reaches 50 at.%. The electrocatalytic activity fall could be attributed to a reduction on active sites favorable to the dissociation and dehydrogenation of methanol. Density functional theory computations reveal that the partial density of states (PDOS) associated with [Mn]3d orbitals could be directly correlated with the observed electrocatalytic behavior. The respective maximum PDOS contribution at the Fermi level also corresponds to the most active electrocatalyst, which contains Mn of ~ 40 at.%.