Ce-doping induced structure evolution in FeNi-based (oxy)hydroxide for highly efficient oxygen evolution reaction

Structure evolution of the catalyst typically plays a key role in determining the catalytic activity in harsh reaction environment. Here we report a doping-reconstruction strategy to prepare catalyst for highly efficient oxygen evolution reaction (OER). Ce-doping has been induced in FeNi metal-organic frameworks (MOFs) to change the microstructure, which can further lead to the in-situ formation of active (oxy)hydroxides. As a result, the obtained Ce-FeNiOOH shows a low overpotential of 196 mV at 10 mA cm⁻², with a small Tafel slope of 33.5 mV dec⁻¹ and a good stability for 100 h. Moreover, by coupling with Pt/C, the two-electrode cell can achieve an excellent performance for overall water splitting with a low voltage of 1.44 V at 10 mA cm⁻² (1.59 V at 100 mA cm⁻²). Synchrotron radiation spectroscopy reveals that Fe-O-Ce microstructure has been created with Ce-doping, which plays a key role for the further transition from MOFs to (oxy)hydroxide during OER.