Novel methanol-tolerant Ir–S/C chalcogenide electrocatalysts for oxygen reduction in DMFC fuel cell

Novel methanol-tolerant oxygen-reduction catalysts, iridium–sulphur (Ir–S) chalcogenides with different Ir/S atomic ratios, were synthesized via a precipitation method using H2IrCl6 and Na2SO3 as the Ir and S precursors. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the IrxS1−x/C chalcogenide catalysts. Particle size ranging from 2.5 to 2.8 nm though obvious agglomeration was found on carbon support. However, these chalcogenide catalysts showed strong catalytic activity towards the oxygen reduction reaction (ORR) and high methanol tolerance, strongly suggesting these novel catalysts as promising candidates for direct methanol fuel cell (DMFC) cathode applications.

Graphical abstractA series of carbon-supported IrxS1−x chalcogenide catalysts was synthesized via precipitation using H2IrCl6 and Na2SO3 as the Ir and S precursors. The chalcogenide with the formula of IrxS1−x/C with x of 0.7 exhibited the highest mass and specific activities. This Ir–S chalcogenide showed high catalytic activity towards the ORR with strong MeOH tolerance.Figure optionsDownload full-size imageDownload as PowerPoint slide