Morphology-Controllable Ni3Se2 Nanostructures; Synthesis, Characterization and Electrocatalytic Activity Towards Oxygen Evolution Reaction

Abstract

First raw transition metal-based chalcogenides (FRTMCs) are promising devices for next generation to serve as effective substitutes for the Pt-based electrocatalysts in fuel cell systems. OER and HER are considered to be clean and sustainable energy technology and an alternative for fossil fuels. However, OER involving a complex 4 electron process, has several steps that have large reaction barriers, which lead to large required overpotentials. Identifying more-efficient, stable and earth-abundant catalysts for water splitting has long been investigated. The planar configuration of FRTMCs could lead to robust integration for electronic devices. Nanostructured electroactive materials that are fabricated in-plane FRTMCs have attracted great attentions as a kind of storage energy material due to its electrochemistry properties. Recently we have observed that Ni-chalcogenide (Ni3Se2) is superior to the precious transition metal oxide-based electrocatalysts in terms of onset overpotential for O2 evolution as well as overpotential to reach a current density of 10 mA cm-2. With the onset of decreasing particle size to nanometric scale, electrodeposition techniques have provided an alternative route to obtain a variety of new nanomaterials with improved and well controlled properties. The improvement of properties of the metallic composites is dependent mainly on the morphology of materials. Morphology-controllable Ni3Se2 films were successfully prepared by electrodepositing Ni3Se2 film on Au substrate and following by electrochemical dissolution. In electrochemical dissolution process, Ni3Se2 phase is well-preserved and porous structure formed. This technology is a promising way to fabricate other porous materials. A porous Ni3Se2 film showed an enhanced OER catalytic performance in comparison with the as-deposited Ni3Se2 film. The results proved that the OER catalytic performance of porous Ni3Se2 film delivers the highest activity. Introduction of pores to the catalyst material by the electrochemical dissolution is availability for improve the electrochemical performance of the material for OER electrocatalysts. The catalytic efficiency of the proposed catalysts was investigated through linear scan voltammetry (LSV), chronoamperommetry and double layer capacitance. Utilizing rotating ring disc electrode (RRDE) assemblies, the kinetics of OER process between various catalysts as well as the Faradaic efficiency were studied. The catalytic activity of the proposed novel compound (Ni3Se2) was also compared to the outstanding electrocatalysts for OER under conditions relevant to an integrated solar water-splitting device which have been reported so far. The synthesis, characterization, catalytic activity and advancement of the field will be presented in details.