Design and Synthesis of Transition Metal- Based Oxygen Catalyst and their Applications in Sustainable Energy Technology

Research output: Book/ReportPh.D. thesis

Abstract

In response to the environmental challenges posed by traditional fossil fuels, there is an urgent demand for clean energy technologies to mitigate greenhouse gas emissions and address global warming. This imperative has driven the exploration of sustainable energy technologies, such as water electrolysis, zincair batteries, and fuel cells, each playing a vital role in reducing dependence on fossil fuels. Water electrolysis offers a pathway for hydrogen production, zinc-air batteries provide an eco-friendly energy storage solution, and fuel cells directly convert chemical energy into electricity with zero emissions. The common thread among these technologies lies in their reliance on efficient oxygen electrocatalysis. This thesis focuses on the design of affordable and stable oxygen electrocatalysts to address the sluggish kinetics of the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR).

The initial part of the thesis concentrates on OER research in oxygen electrocatalysis, specifically the synthesis of Fe-doped metal-organic cobalt hydroxide (Fe0.2Co0.8(OH)(Hsal)). Employing a straightforward and cost-effective synthesis method without the need for complex surfactants, the study investigates the impact of Fe doping on the catalyst through XPS and in situ electrochemical impedance spectroscopy (ESI) tests. Results indicate that Fe0.2Co0.8(OH)(Hsal) outperforms Co(OH)(Hsal) in OER performance, attributing this improvement to introduced defects and altered surface electronic structure. Morphological and structural characterizations confirm the positive impact of Fe introduction, revealing lower resistance and higher catalytic activity in Fe0.2Co0.8(OH)(Hsal), suggesting its broad applicability in OER. The incorporation of Fe demonstrates a universally positive influence on the performance of single metal catalysts, presenting wide-ranging applicability in the development of catalysts for the oxygen evolution reaction (OER). This advancement is poised to yield oxygen electrocatalysts that are not only more effective but also cost-efficient.

The second part explores the ORR aspect of oxygen electrocatalysis. Pt-FeNC, synthesized on single-atom transition metal-nitrogen-carbon (TMNC) materials through photoreduction, demonstrates excellent performance compared to commercial Pt/C. This catalyst exhibits outstanding ORR performance and stability in rechargeable zinc-air batteries (ZABs), positioning it as a potential catalyst for advancing sustainable energy technologies. To address the cost concerns associated with precious metal platinum in proton exchange membrane fuel cell (PEMFC) systems, Pt-Co electrocatalysts derived from zeolitic imidazolate frameworks (ZIFs) showcase the potential to maintain high initial activity and durability at low platinum loadings. Using an electrospun polyacrylonitrile (PAN) substrate, the study forms Pt-Co nanoparticles through ZIF structure growth and heat treatment, demonstrating superior ORR activity and providing a promising way to reduce the usage of Pt in PEMFC systems.
Original languageEnglish
Place of PublicationKgs. Lyngby
PublisherTechnical University of Denmark
Number of pages108
Publication statusPublished - 2024

Fingerprint

Dive into the research topics of 'Design and Synthesis of Transition Metal- Based Oxygen Catalyst and their Applications in Sustainable Energy Technology'. Together they form a unique fingerprint.

Cite this