The 3d-4f electron transition of the CoS 2 /CeO 2 heterojunction for efficient oxygen evolution.

CoS 2 /CeO 2 , exhibiting the 3d-4f orbital coupling effect, is developed and shows exceptional OER activity, with an overpotential of 140 mV at 10 mA cm -2 . DFT calculation and Raman spectra show the existence of a d-p-f electron transport ladder that can accelerate electron transfer through the Co-O(S)-Ce bond, optimize the adsorption free energy, and enhance the catalytic activity.