Based on theoretical simulations, the best design for obtaining AgPt nanostructures (nanoshells with hollow interior) was unraveled that could exhibit methanol tolerance for oxygen reduction reaction (ORR) that occurs during direct methanol fuel cells (DMFCs) operation. A theoretical investigation of Pt@Ag and Ag@Pt core-shell nanoparticles and AgPt nanoshells' interaction with oxygen and methanol revealed that the oxygen interaction is significantly more favorable on AgPt nanoshells' surface, hindering the methanol oxidation reaction (MOR) due to the random arrangement of Ag and Pt atoms. Experimentally, the nanoshells were prepared by a galvanic substitution and immobilized them onto silica, and the material was finely understood by associating electrochemical and physicochemical studies. Cyclic voltammetry showed the reduction and oxidation processes of the catalyst's species; however, XPS precisely showed that significant amounts of oxidized species were present (60.5 % of Ag 0 and 39.5 % of Ag + , and 55.1 % of Pt 0 and 44.9 % of Pt + 2 ), which could affect the performance of the material. Indeed, the catalyst showed an excellent performance to ORR; the system yielded a 4-electron ORR mechanism with just 1.0 wt.% Pt loading, with significant stability after 1000 runs. In addition, Koutecky-Levich and Tafel plots assisted in understanding better the mechanism on the catalyst's surface, suggesting a first-electron transfer for the rate-determining step. Also, the catalyst resistance to the methanol crossover, theoretically simulated and predicted, was tested, showing remarkable tolerance for the alcohol up to a concentration of 2 M. Hence, a cathode catalyst with improved selectivity, low metal loading, high stability, and easy preparation was obtained.
The Front Cover shows that nanoengineering is a breakthrough way to look at the electrocatalysis field under a different perspective. In their Research Article, M. Aurélio Suller Garcia, T. Silva Rodrigues and co‐workers provided the design of a hollow AgPt‐based electrocatalyst with improved resistance to methanol for Direct Methanol Fuel Cells applications. After immobilization onto SiO2, the nanostructures presented remarkable stability, with a four‐electron oxygen reduction reaction mechanism as the Pt/C commercial catalyst, with 20 times less Pt content. More information can be found in the Research Article by M. Aurélio Suller Garcia, T. Silva Rodrigues and co‐workers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.