(Digital Presentation) Electrospun Bimetallic Cu/Zn Selenide @ Carbon Nanofiber Electrocatalysts for Oxygen Evolution and Oxygen Reduction

Abstract

Electrochemical water splitting and fuel cells are intriguing ways to achieve a potentially sustainable and clean energy1. A greater focus on these energy technologies necessitates the design and development of highly active, cost-effective electrocatalysts that can substitute state of the art noble metal based materials2. In this context, metal selenide-based materials are important owing to their superior stability and electrical conductivity3. Their high specific surface area and abundant active sites on the surfaces make them strong candidates for use as electrocatalysts. Herein, heterostructured copper selenide and zinc selenide encased in carbon nanofibers (CZSe@C-450) synthesized using electrospinning and selenization techniques are used as bifunctional electrocatalysts. The novel architecture and tunable confinement of bimetallic selenides with the carbon matrix results in improved electrochemical performance in both oxygen evolution (OER) and oxygen reduction reactions (ORR)4. CZSe@C-450 exhibits a low overpotential of 260 mV at 10 mA cm−2 for oxygen evolution reaction and exhibits a half-wave potential (E1/2) of 0.88 V for oxygen reduction reaction. Further, the creation of a heterogeneous phase boundary between copper selenide and zinc selenide in the CZSe@C-450 enhances the built-in potential, local atomic disorder, and mismatch in the lattice that leads to lowering the surface energy. This gives rise to creation of catalytically active edge sites and phase boundaries, which contribute to the enhanced performance and good stability in both OER and ORR5,6.