电化学重构NiOOH/NiFeV-LDH@CC用于高效析氧反应OA

The surface reconstruction of NiFe-based layered double hydroxide(LDH)electrocatalysts has been widely studied.The reconstructed NiOOH phase plays a critical role in improving the oxygen evolution reaction(OER)perform-ance of NiFe-based LDHs,but observing the NiOOH phase is difficult because of its instability and exploring the functional mechanism of NiOOH in NiFe-based LDHs remains a great challenge.A simple electrochemical activation was used to synthesize a NiOOH/NiFeV-LDH@CC catalyst consisting of an array of V-doped NiFe-LDH nanosheets on carbon cloth(CC),in which the reconstructed NiOOH phase is the active species.During electrochemical activation,the release of doped V leads to the formation of abundant vanadium vacancy(VV)and oxygen vacancy(VO)species,and thus the surface of the NiFe-LDH nanosheets is reconstructed to form NiOOH.Because of the improved intrinsic activity from the NiOOH active phase,and the increased electrical conductivity produced by the abundant VO,NiOOH/NiFeV-LDH@CC has an excellent OER performance in an alkaline solution,with low overpotentials of 209 mV and 241 mV at 20 mA cm-2 and 100 mA cm-2,respect-ively.It also has a long-term stability of 80,000 s at a constant current density of 10 mA cm-2.Using NiOOH/NiFeV-LDH@CC as the anode,an assembled over water splitting(OWS)battery can drive a current density of 20 mA cm-2(without iR compens-ation)at a much lower voltage of 1.597 V.At the same time,the electrolytic cell can deliver a current density of 10 mA cm-2 at～1.55V for more than 80,000 s without significant loss.This electrochemical activation method can be used in future designs of electrocatalysts for OER.