Investigation of Platinum Dispersed on Reduced Graphene Oxide-supported Tungsten Carbide via Sacrificial Cu Adlayers for Methanol Oxidation

Reduced graphene oxide-supported tungsten carbide composite (WC/RGO) was prepared by program-controlled reduction-carburization technique. Scanning electron microscope (SEM) and transmission electron microscope (TEM) show that WC nanoparticles with a narrow distribution (10-20 nm) are highly dispersed both on the edge and between the layers of RGO. And then it was used as a support to load different low contents (no more than 0.4 wt%) of Pt via sacrificial Cu adlayers. The morphology and the electrocatalytic activity of the prepared catalysts were characterized by TEM and cyclic voltammograms (CV), respectively. The results indicate that a small amount of isolated Pt atoms show low or even no activity for methanol oxidation. With the increasing deposition cycles, the content of Pt and the ensembles of neighboring Pt atoms are increased, which makes the onset potential shift negatively and mass current density increase. The results demonstrate that controllable amount of Pt can be deposited on WC/RGO by galvanic displacement with Cu, and the extent and domain of Pt loading affect the electrochemical performance. Meanwhile, this research also provides another route to prepare a catalyst with ultra low noble metal on WC/RGO for solving the problem of high cost of the catalyst.