In the present study, a carbon nanotube supported platinum (Pt/CNT) electrode with a thin and uniform ionomer layer as the proton-conducting electrolyte on a nano patterned three-phase zone (TPZ) was fabricated, aiming at high electrocatalytic activity and high charge transfer rate for methanol oxidation reaction (MOR). Unlike conventional paste or spray methods that produced thick and non-uniform ionomer layers to form TPZs within the catalyst layers (50-100 mu m) of electrodes, thin and uniform ionomer layers (5-10 nm) on the hydrophilic-treated Pt/CNT catalyst electrodes (8 mu m) were harvested by spin-coating. The thickness of the ionomer layer was controlled by altering the spin-coating speed, and the effect of the ionomer thickness on the surface of the catalyst layer and on the electrochemical properties of the electrodes for MOR was studied (mass activity, MA and charge transfer resistance, Rct). Compared to the electrode fabricated by spraying (MA: 355 A g(-1), Rct: 48 Omega cm(2)), the ionomer-coated electrode spin-coated at 4000 rpm exhibited superior properties for MOR (MA: 381 A g(-1), Rct: 15 Omega cm(2)). The outcome renders this new electrode to embrace potential applications in micro direct methanol fuel cells (mu DMFCs) with the design of a thin and uniform TPZ. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.041207jes] All rights reserved.