Chen, S.Duan, J.Bian, P.Tang, Y.Zheng, R.Qiao, S.2015-10-012015-10-012015Advanced Energy Materials, 2015; 5(18):1-71614-68321614-6840http://hdl.handle.net/2440/94970A multifunctional catalyst electrode mimicking external stimuli–responsive property has been prepared by the in situ growth of nitrogen (N)-doped NiFe double layered hydroxide (N–NiFe LDH) nanolayers on a 3D nickel foam substrate framework. The electrode demonstrates superior performance toward catalyzing oxygen evolution reaction (OER), affording a low overpotential of 0.23 V at the current density of 10 mA cm −2 , high Faradaic efficiency of ≈98%, and stable operation for >60 h. Meanwhile, the electrode can dynamically change its color from gray silver to dark black with the OER happening, and the coloration/bleaching processes persist for at least 5000 cycles, rendering it a useful tool to monitor the catalytic process. Mechanism study reveals that the excellent structural properties of electrode such as 3D conductive framework, ultra thickness of N–NiFe LDH nanolayer (≈0.8 nm), and high N-doping content (≈17.8%) make significant contribution to achieving enhanced catalytic performance, while N–NiFe LDH nanolayer on electrode is the main contributor to the stimuli-responsive property with the reversible extraction/insertion of electrons from/into N–NiFe LDH leading to the coloration/bleaching processes. Potential application of this electrode has been further demonstrated by integrating it into a Zn–air battery device to identify the charging process during electrochemical cycling.en© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimJournal article003003470910.1002/aenm.2015009360003621615000122-s2.0-84942872360210341Qiao, S. [0000-0002-1220-1761] [0000-0002-4568-8422]