Performance of vertically oriented graphene supported platinum-ruthenium bimetallic catalyst for methanol oxidation

This work reports the electrocatalytic performance of vertically oriented graphene (VG) supported Pt-Ru bimetallic catalysts toward methanol oxidation reaction (MOR). Dense networks of VG are directly synthesized on carbon paper (CP) via a microwave plamsa-enhanced chemical vapor deposition (PECVD) method. A repeated pulse potentials approach is applied in a conventional three-electrode electrochemical system for the co-electrodeposition of Pt-Ru bimetallic nanoparticles. It is found that, the decoration of VG can simultaneously lead to a similar to 3.5 times higher catalyst mass loading and a similar to 50% smaller nanoparticle size than the pristine CP counterparts. An optimum Pt molar ratio of 83.4% in the deposits, achieved with a [H2PtCl6]:[RuCl3] of 1:1 in the electrolyte, is clarified with synthetically considering the mass specific activity, CO tolerance, and catalytic stability. According to Tafel analysis and cyclic voltammetry (CV) tests, the Pt-Ru/VG catalyst with the optimized Pt molar ratio can realize a faster methanol dehydrogenation than Pt/VG, and present a significantly enhanced catalytic activity (maximum current density of 339.2 mA mg(-1)) than those using pristine CP and Vulcan XC-72 as the supports. (C) 2014 Elsevier B.V. All rights reserved.