This paper utilizes high-speed compressive Raman imaging to investigate the oxygen evolution reaction (OER) in α-Li₂IrO₃, a crystalline electrocatalyst. The study reveals bias-dependent OER pathways, showing that at low overpotentials, the reaction is compensated by bulk ion exchange, while at high overpotentials, charge compensation occurs via surface redox sites. This demonstrates that charge compensation can extend beyond the surface in crystalline catalysts. The compressive Raman imaging technique is highlighted as a powerful tool for tracking microscale reaction dynamics in various materials.

Raj Pandya, Florian Dorchies, Davide Romanin, Jean-François Lemineur, Frédéric Kanoufi, Sylvain Gigan, Alex W. Chin, Hilton B. de Aguiar, Alexis Grimaud