Ce-induced dynamic electron buffering to regulate controllable surface reconstruction of Co for alkaline oxygen evolution reaction
Transition metal hydroxides are promising oxygen evolution reaction (OER) catalysts for alkaline water electrolysis. This study reports Ce-doped Co(OH)2 electrocatalysts synthesized via one-step electrodeposition, where the Ce3+/Ce4+ ratio is precisely controlled by deposition temperature. The optimized Ce-Co(OH)2 catalyst, obtained at 40°C, exhibits an overpotential of 236 mV at 10 mA cm-2 and maintains stability for 200 h. In an anion-exchange membrane water electrolyzer (AEMWE), the Ce-Co(OH)2 anode achieves a cell voltage of 2.04 V at 1 A cm-2 and operates for over 500 h at 500 mA cm-2. Mechanistic analysis reveals that Ce3+/Ce4+ dynamic electron buffering regulates surface reconstruction: during OER, electron transfer direction reverses (Ce → O → Co), with Ce donating electrons to Co sites to prevent over-oxidation and structural collapse. This work establishes a versatile strategy for balancing surface reconstruction and structural stability in Co-based OER catalysts, providing a foundation for designing high-performance, durable alkaline water oxidation electrocatalysts.