Novel Nanocomposite Pt/RuO_2.xH_2O/Carbon Nanotube Catalysts for Direct Methanol Fuel Cells

摘要

Two key problems inhibiting the commercialization of direct methanol fuel cells (DMFCs) are the cost of the precious metals employed and the sluggish kinetics and catalyst poisoning by CO or CHO species. Research to solve the first drawback[1]-[4] focuses on the reduction of precious metal loading, which is achieved by increasing the catalyst's specific surface area and its accessibility. For the second problem, advanced electrocatalyst design relies on the bifunctional approach,[5]-[10] in which a second compound such as ruthenium or RuO2x H2O assists the oxidation of CO or CHO species by adsorption of oxygen-containing species close to the poisoned Pt sites. In contrast to previous work on PtRu alloy catalysts,[11]-[13] Rolison and co-workers[14], [15] emphasized the importance of hydrous ruthenium oxides because the RuO2x H2O speciation of Ru in nanoscale PtRu blacks shows both high electron and proton conductivity, which results in a much more active catalyst for methanol oxidation. However, direct evidence of the catalytic function of hydrous oxides is very scarce.