Electrospun One-Dimensional Electrocatalysts for Oxygen Reduction Reaction: Insights into Structure–Activity Relationship

Abstract

Oxygen reduction reaction (ORR) is an efficiency-determining process at the cathode in several energy storage and conversion devices, typically such as metal-air batteries and fuel cells. To date, a considerable amount of ORR electrocatalysts have been purposely exploited to address the key issues of high overpotentials and sluggish electrochemical kinetics. Electrospinning is a popular additive manufacturing technology, enabling the production of one-dimensional (1D) electrocatalysts with outstanding chemical stability and structural diversity. However, compared with the well-studied composite/structural design as well as performance advancement, insights into structure–activity relationship are yet to be settled. To clarify this key issue, herein, a dedicated review on the structure–activity relationship between the 1D architectures of electrospun electrocatalysts and their catalytic ORR property is presented. First, the development and principles of electrospinning technique, the composition regulation- and structure design-oriented fundamentals are summarized by imputing the perspectives of mechanistic understanding. Then, the typical examples of nanofiber-shaped and nanofiber-supported electrocatalysts with different compositions and structures for ORR are implemented to establish different structure–activity relationship by comparative studies. Finally, we also identify some ongoing challenges and present future perspectives to direct the precise manipulation of structure–activity relationship for further activation and optimization of electrospun 1D electrocatalysts.

Electrospun one-dimensional electrocatalysts for boosting electrocatalysis

“…1). 45 A syringe pump is usually involved to ensure a stable and controllable infusion rate of the polymer solution. And the forming process of electrospun materials usually involves the following consecutive procedures.…”

“…[42][43][44] Among them, the 1D nanofibers and nanotubes gradually appealed to the interest of scientists, due to the advantages of large specific surface area, high aspect ratio, and efficient electron transfer. 45 Nowadays, numerous synthetic strategies have been proposed to generate fiber-shaped materials such as hydrothermal synthesis, chemical vapor deposition, and electrospinning, among which electrospinning provides a simple and versatile platform for the creation of 1D nanomaterials with tunable composition and nanostructures. In addition, it is also reported that electrospinning methods are ecofriendly and economical for the production of 1D fiber-shaped or tube-like nanomaterials with controllable architectures.…”

“…42–44 Among them, the 1D nanofibers and nanotubes gradually appealed to the interest of scientists, due to the advantages of large specific surface area, high aspect ratio, and efficient electron transfer. 45…”

From 1D Nanofibers to 3D Nanofibrous Aerogels: A Marvellous Evolution of Electrospun SiO2 Nanofibers for Emerging Applications

“…Among these techniques, the electrospinning is a simple and versatile approach for producing 1D nanofibers from a wide variety of materials, with representative examples including metals, polymers, ceramics, and organic–inorganic composites [ 16 – 18 ]. Unlike other ways for generating 1D nanomaterials, the nanofibers obtained by electrospinning have obvious advantages in composition control, structure design, and function expansion [ 19 – 21 ]. Moreover, the electrospun nanofibers combine distinctive features such as fine diameter, large specific surface area, and high porosity, thus meeting the needs of diverse applications [ 22 – 24 ].…”

1D confined materials synthesized via a coating method for thermal catalysis and energy storage applications

“…for environmental applications, 60 modified TiO 2 confined catalysts for photo-catalysis, 61 and 1D materials prepared using the electro-spinning method for the oxygen reduction reaction (ORR). 62 However, 1D catalysts confined within SiO 2 , TiO 2 , CeO 2 NTs etc. via the coating method for thermal catalysis have not been systematically reviewed.…”