Fabrication and electrochemical activity of carbon nanotubes decorated with PtRu nanoparticles in acid solution

A series of carbon nanotubes (CNTs) decorated with bimetallic platinum/ruthenium nanocatalysts were fabricated to investigate their electrochemical activities in acid solution. These PtRu/CNT composites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and N2 physisorption. The crystalline size of PtRu nanocatalysts generally decreased with Ru atomic ratio, i.e., from 4.34 to 2.77 nm. The specific surface areas and pore size distributions of PtRu/CNT composites were slightly altered after the PtRu deposition. Cyclic voltammetry measurements in 1 M H2SO4 showed that Pt75Ru25/CNT electrode has the greatest activity in electrochemical adsorption and desorption of hydrogen, i.e., the ratio of electrochemical surface coverage: 84.6%. This enhancement of electrochemical activity was attributed to two possible reasons: (i) addition of Ru in the bimetallic catalysts leads to reduce the required potential for water electrolysis and thus the associated carbon oxidation; (ii) the presence of Ru in the bimetallic alloys acts an important role in regenerating inactive Pt-COads sties.