A phase transformation-free redox couple mediated electrocatalytic oxygen evolution reaction

Abstract

NiFe layered double hydroxide (NiFe-LDH), as a promising non-noble catalyst for oxygen evolution reaction (OER), suffers from the high OER barriers during NixFe1−x(OH)2/NixFe1−xOOH interconversion. To solve this problem, we highly dispersed the 2–3 nm CeO2−x particles on single-layered NiFe-LDH to form CeO2−x/NiFe-LDH heterostructure by a one-step co-precipitation method. CeO2−x, as an electron acceptor, can extract electrons from Ni sites of NiFe-LDH via Ni-O-Ce electron exchange effect, thus achieving direct Ni2+/Ni3+ electron transfer with no need of NixFe1−x(OH)2/NixFe1−xOOH phase transformation. As a result of efficient electron transfer by strong interface interactions between CeO2−x and NiFe-LDH, the CeO2−x/NiFe-LDH exhibits excellent OER performance with a low OER overpotential of 216 mV at 10 mA cm−2 and a Tafel slope of 74.1 mV dec−1. Our work provides a new strategy to improve the OER performances of NiFe-based materials.