Dimethyldiallylammonium chloride (DMDAAC) modified reduced graphene oxide supported Pd nanopartides (Pd/DMDAAC-RGO) were fabricated by polyol microwave heating method. The Pd/DMDAAC-RGO hybrid were characterized by transmission electromicroscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis and electrochemical tests. High Pd metal loadings, up to 80 wt. % with a mean size of 1.8 nm, were densely in situ decorated on DMDAAC-modified RGO surfaces. Compared with traditional carbon-based Pd catalysts, Pd/DMDAAC-RGO exhibits better activity and stability for ethanol oxidation in alkaline media with the same Pd content on the electrode. This improved activity indicates that DMDAAC plays a crucial role in the dispersion and stabilization of Pd nanopartides on RGO sheets and DMDAAC-RGO are able to an alternative support for Pd immobilization in direct ethanol fuel cells and other catalytic devices. (c) 2013 Elsevier Ltd. All rights reserved.