Regulating the active species of Ni(OH)2 using CeO2: 3D CeO2/Ni(OH)2/carbon foam as an efficient electrode for the oxygen evolution reaction
Three dimensional (3D) N, O and S doped carbon foam (NOSCF) is prepared as a substrate for in situ vertically grown Ni(OH)2 nanosheets. As designed Ni(OH)2/NOSCF possesses strong electrostatic interactions with OH− ions due to many CO groups existing in NOSCF, which can facilitate the formation of crucial NiOOH intermediates during the OER process. CeO2 nanoparticles (NPs) of ∼3.3 nm in size are decorated on Ni(OH)2 nanosheets to design a highly efficient CeO2/Ni(OH)2/NOSCF electrocatalyst for the oxygen evolution reaction (OER). The CeO2 NP decorated Ni(OH)2/NOSCF not only exhibits a remarkably improved OER performance with an onset potential of 240 mV, outperforming most reported non-noble metal based OER electrocatalysts, but also possesses a small Tafel slope of 57 mV dec−1 and excellent stability under different overpotentials. The synergistic effect of producing more active species of NiIII/IV and accelerating the charge transfer for Ni(OH)2/NOSCF by the introduction of CeO2 NPs is also investigated. These results demonstrate the possibility of designing energy efficient OER catalysts with the assistance of earth abundant CeO2-based catalysts.