Three-dimensional cubic ordered mesoporous carbon (CMK-8) as highly efficient stable Pd electro-catalyst support for formic acid oxidation

In this work, Pd nanoparticles were supported on two types of three-dimensional cubic highly ordered
mesoporous carbon (CMK-8) by the sodium borohydride reduction method and the activity of the Pd/
CMK-8 electro-catalysts towards formic acid oxidation was evaluated and compared with that of
commercial Pd/C (E-TEK) catalyst. The catalysts were characterized by transmission electron microscopy
(TEM), X-ray diffraction (XRD), cyclic voltammetry, and chronoamperometry. Cyclic voltammetry
revealed Pd/CMK-8 with larger pores as being the most electroactive with a mass specific activity
(mA mgPd
1) of 486.4 that exceeded not only that of the Pd/C (E-TEK) (386.5 mAmgPd
1) but also that of
recently reported Pd/CNT (200 mAmgPd
1), Pd/Graphene (210mAmgPd
1) and Pd/Vulcan XC 72 (193mAmgPd
1).
As demonstrated with chronoamperometry, the larger pore Pd/CMK-8 also proved to be the most stable
catalyst. This exceptional performance can be ascribed to the very high surface area and Ia3d symmetry
that yields a relatively isotropic graphitized structure with a high conductivity. In addition, the open
framework of the 3-D bicontinous channels and highly ordered mesopores allows for an advanced mass
transfer characteristics. The results show that CMK-8 support would significantly improve the power
output and stability of Pd-based electro-catalysts for formic acid oxidation.