1 research outputs found
La<sub>2</sub>O<sub>3</sub> Promoted Pd/rGO Electro-catalysts for Formic Acid Oxidation
High activity, a low rate of CO poisoning,
and long-term stability of Pd electro-catalysts are necessary for
practical use as an anode material in direct formic acid fuel cells.
Achieving a high degree of Pd nanoparticle dispersion on a carbon
support, without agglomeration, while maintaining a facile electron
transfer through the catalyst surface are two challenging tasks to
be overcome in fulfilling this aim. Herein, we report the effect of
addition of La/La-oxides on the efficiency of Pd nanoparticles supported
on reduced graphene oxide (rGO) for formic acid electro-oxidation
reaction. A series of electro-catalysts with different Pd–La
molar ratios were successfully synthesized and characterized using
a range of techniques including PXRD, XPS, TEM, FTIR, and Raman spectroscopy
and then tested as anode materials for direct formic acid fuel cells.
We explore that the lanthanum species (La/La-oxide) significantly
promote the activity and stability of Pd catalyst toward electrocatalytic
oxidation of formic acid. The metallic ratio is found to be critical,
and the activity order of various catalysts is observed as follows;
Pd<sub>30</sub>La<sub>70</sub>/rGO > Pd<sub>80</sub>La<sub>20</sub>/rGO > Pd<sub>70</sub>La<sub>30</sub> rGO. The obtained mass specific
activity for Pd<sub>30</sub>La<sub>70</sub>/rGO (986.42 A/g) is 2.18
times higher than that for Pd/rGO (451 A/g) and 16 times higher than
that for Pd/C (61.5 A/g) at given onset peak potentials. The high
activity and stability of the electro-catalysts are attributed to
the uniform dispersion of Pd nanoparticles over the rGO support, as
evidenced from TEM images. It is believed that the role of La species
in promoting the catalyst activity is to disperse the catalyst particles
during synthesis and to facilitate the electron transfer via providing
a suitable pathway during electrochemical testing