Carbon supported ruthenium chalcogenide as cathode catalyst in a microfluidic formic acid fuel cell

This work reports the electrochemical measurements of 20 wt.% Ru_xSe_y/C for oxygen reduction reaction (ORR) in presence of different concentration of HCOOH and its use as cathode catalyst in a microfluidic formic acid fuel cell (μFAFC). The results were compared to those obtained with commercial Pt/C. Half-cell electrochemical measurements showed that the chalcogenide catalyst has a high tolerance and selectivity towards ORR in electrolytes containing up to 0.1 M HCOOH. The depolarization effect was higher on Pt/C than on Ru_xSe_y/C by a factor of ca. 23. Both catalysts were evaluated as cathode of a μFAFC operating with different concentrations of HCOOH. When 0.5 M HCOOH was used, maximum current densities of 11.44 mA cm⁻² and 4.44 mA cm⁻² were obtained when the cathode was Ru_xSe_y/C and Pt/C, respectively. At 0.5 M HCOOH, the peak power density of the μFAFC was similar for both catalysts, ca. 1.9 mW cm⁻². At 5 M HCOOH the power density of the μFAFC using Ru_xSe_y, was 9.3 times higher than the obtained with Pt/C.