Manipulating the Corrosion Resistance of SnO2 Aerogels through Doping for Efficient and Durable Oxygen Evolution Reaction Electrocatalysis in Acidic Media

Implementing iridium oxide (IrOx) nanocatalysts can be a major breakthrough for oxygen evolution reaction (OER), the limiting reaction in polymer electrolyte membrane water electrolyzer devices. However, this strategy requires developing a support that is electronically conductive, is stable in OER conditions, features a large specific surface area and a porosity adapted to gas-liquid flows. To address these challenges, we synthesized IrOx nanoparticles, supported them on doped SnO2 aerogels (IrOx/doped SnO2), and assessed their electrocatalytic activity toward the OER and their resistance to corrosion in acidic media by means of a flow cell connected to an inductively coupled mass spectrometer (FC-ICP-MS). The FC-ICP-MS results show that the long-term OER activity of IrOx/doped SnO2 aerogels is controlled by the resistance to corrosion of the doping element, and by its concentration in the host SnO2 matrix. In particular, we provide quantitative evidence that Sb-doped SnO2 supports continuously dissolve while Ta-doped or Nb-doped SnO2 supports with appropriate doping concentrations are stable under acidic OER conditions. These results shed fundamental light on the complex equilibrium existing between SnO2 and the doping element oxide. They also open a reliable path to develop highly active and robust IrOx nanocatalysts for OER in acidic media.