Rhodium nanodendrites catalyzed alkaline methanol oxidation reaction in direct methanol fuel cells

Rh-based nanostructures are highly efficient Pt-alternative anode electrocatalysts for alkaline direct methanol fuel cells due to their high electroactivity for methanol oxidation reaction (MOR) in strong alkaline electrolyte. In this work, high-quality chlorine-free Rh nanodendrites (Rh-NDs) are easily synthesized by simple one-step chemical-reduction method. Physical characterization show that the appropriate reduction rate plays a pivotal role for the formation of Rh-NDs. Electrochemical results indicate that both methanol concentration and KOH concentration strongly determine the peak current value of MOR at Rh-NDs. Under optimal experiment conditions (3 M KOH concentration and 5 M methanol concentration), Rh-NDs show 3.17-fold electroactivity enhancement and enhanced durability for MOR relative to irregular Rh nanocrystals because the dendritic morphology not only provides the large specific surface area and rich corner/edge atoms with high electroactivity but also efficiently restrains the aggregation of nanoparticle subunits.