Synthesis of PtMe/rGO (Me=Ni, Co, Al, Al-Si) catalysts with high electrochemical performance for ethanol oxidation

Abstract

In the study, several Pt-based anode catalysts supported on reduced graphene oxide (rGO) were prepared and characterized by means of TEM, Raman, and EDX. Good particle dispersion onto the graphen support, similar particle sizes (around 2÷20 nm), and the presence of promoters were observed in all cases. Their electrochemical propeties were investigated by cyclic voltammetry and chronoamperometry in alkaline media. Notably, electrochemical tests showed that the presence of Al, Si, Co, and Ni enhanced the activity of Pt towards ethanol electro-oxidation in the following order: Pt_11,5Al_12,7/rGO ≈ Pt_22,1Al_1,7Si_3,1/rGO >> Pt2,4Ni_11,1/rGO > Pt_2,5Co₁₄/ rGO > Pt_20,5/rGO. In particular, Pt_11.5Al_12.7/rGO catalyst exhibited the best catalytic stability for ethanol oxidation. The presences of Al and Al-Si improved the dispersion of Pt nanoparticles on the surface of rGO, which is assumed to be the main reason for improving the activity and stability of the catalysts. Besides, the Pt22.1Al1.7Si3.1/rGO catalyst, with a small amount of Si and Al, has the catalytic activity comparable to the activity of the Pt_11.5Al_12.7/rGO catalyst, with a large amount of Al. The remarkable improvement of the ethanol electro-oxidation activity was found in alkaline media, providing potential applications of these materials as catalysts for alkaline direct ethanol fuel cells.