Carbon nanobowl supported chemically functionalized PtRh nanocrystals: a highly active and methanol tolerant electrocatalyst towards the oxygen reduction reaction

The cathodic oxygen reduction reaction (ORR) is a key half-reaction for direct methanol fuel cells (DMFCs). Enhancing the electroactivity and selectivity of cathodic Pt-based ORR electrocatalysts is pivotal for accelerating the commercialization of DMFCs because of the scarcity of Pt metal and the inherent electroactivity of Pt-based electrocatalysts towards the methanol electrooxidation reaction. Herein, highly dispersed carbon nanobowl (CNBs) supported 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid (BmimBF(4)) functionalized Pt1Rh1 alloy nanocrystal nanohybrids (Pt1Rh1@BmimBF(4)/CNBs) are successfully synthesized by reducing mixed BmimBF(4)-Pt-II and BmimBF(4)-Rh-III complex precipitates with NaBH4 solution. During the reduction process, PtRh alloy nanocrystals are simultaneously functionalized by BmimBF(4) because of the strong N-metal interaction. Pt1Rh1@BmimBF(4)/CNBs nanohybrids with the optimal chemical composition reveal significantly enhanced ORR electroactivity and fascinating ORR selectivity (i.e., methanol tolerance) compared to Pt1Rh1/CNBs nanohybrids without BmimBF(4) because of the carrier effect, alloy effect, and particular metal-organic interface.