A bifunctional electrocatalyst based on interfacial engineering of CeO2 and NiSe2 for boosting electrocatalytic water splitting

Herein, a novel self-supported bifunctional electrocatalyst with a three-dimensional core–shell structure of NiSe2 nanoparticles encapsulated by CeO2 films is reported. It has the following advantages: (i) the high conductivity of nickel foam substrate self-supported NiSe2 efficient for favorable electron transfer, (ii) interconversion of Ce4+ and Ce3+ for efficiently optimizing the energetics of OER intermediates based on density functional theory simulations, and (iii) interfacial engineering between NiSe2 nanoparticles and CeO2 for efficacious oxygen ion exchange and electronic transmission. CeO2–NiSe2 demonstrates excellent overpotentials of 125 mV and 72 mV for the OER and the HER at 10 mA cm−2, respectively, and superior long cycling stability. Moreover, a low voltage of 1.56 V is demonstrated when CeO2–NiSe2 is utilized as self-supported electrodes for the total water splitting reaction. This discovery is expected to provide a new approach for the synthesis of efficient bifunctional electrocatalysts and regeneration of clean energy.