Research On ZnO-Nanwire Array-Based Electrocatalysts With Heterostructure For The Oxygen Evolution Reaction

Developing highly efficient,low-cost and stable electrocatalyst for the oxygen evolution reaction?OER?is essential for hydrogen production by electrolyzing water.In recent years,transition metal based materials have attracted extensive attention in the field of electrocatalytic for OER due to their low cost,easy availability and high activity.However,the catalytic activity needs to be further improved before they can be widely used.In this paper,Zn O/Co₃O₄ and Zn O/Fe OOH composites are fabricated on nickel foil?NF?substrate respectively,and used as high-active OER catalyst in alkaline solution,due to their 1D nano-structure,heterostructure and rich oxygen vacancy.The main research contents are as follows:?1?Zn O/Co₃O₄ p-n heterojunction nanocomposite array is fabricated on NF substrate by a mild photo-deposition method.The influence of the photodeposition time on the morphology and OER performance of the composite is studied.The results show that compared with sole Co₃O₄,the Zn O/Co₃O₄ nanocomposite array exhibits larger electrochemical active surface area?ECSA?and smaller charge transfer resistance(R_ct).The as-fabricated Zn O/Co₃O₄ nanocomposite array photodeposited for 4 hours exhibits the most excellent electrochemical performance for OER.?2?Zn O/amorphous-Fe OOH heterostructure nanorods array is prepared on NF substrate via a simple chemical bath method.We discuss the influence of the immersion time on the morphology and OER performance of the composite.The results indicate that compared with sole Fe OOH,Zn O/Fe OOH nanorods show larger ECSA and smaller R_ct.The atomic Fe:Zn ratio of Zn O/Fe OOH nanorods changes with the immersion time,and influences the OER performance.The as-prepared Zn O/Fe OOH nanorods with 10 minutes immersion time show best electrocatalytic performance for OER.?3?The electrocatalytic mechanism of Zn O/Co₃O₄ nanocomposite array and Zn O/Fe OOH nanorods is studied by X-ray photoelectron spectroscopy?XPS?,the results reveal that the strong electron interaction on Zn O/Co₃O₄?Zn O/Fe OOH?nanointerfaces promotes interfacial charge transfer from Co?Fe?to Zn,and further cooperates synergistically toward the oxygen generation in alkali solution.Besides,Zn O/Co₃O₄ and Zn O/Fe OOH possess abundant oxygen vacancy,which is one of the main reasons for the high catalytic activity for OER.